Williamson-Thermoflo GWC-070, GWC-105, GWC-140, GWC-175 User Manual

Download

Model

GWC

Series 2

Gas-Fired Water Boilers

Boiler Manual

• Installation

• Startup

• Maintenance

• Parts

This manual must only be used by a qualiﬁed

heating installer/service technician. BEFORE installing, read all instructions in this manual and all other information shipped with the boiler. Perform steps in the order given. Failure to comply could result in severe personal injury, death or substantial property damage.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

How it works . . .

1 Integrated boiler control

The integrated boiler control (IBC) responds to signals from the room thermostat, air pressure switch, inlet water sensor, boiler water temperature sensor and boiler limit circuit to operate the circulators, gas valve, igniter and blower. When a room thermostat calls for heat, the IBC starts the system circulator and blower. The IBC runs the blower to purge the boiler ﬂue passages, then turns on the igniter and lets it warm up. After igniter warm-up, the IBC opens the gas valve, turns the igniter off, and checks for ﬂame. The ﬂame must come on within 4 seconds or the IBC will shut down and try the full cycle again. When the room thermostat is satisﬁed, the IBC turns off the boiler components and waits for the next heat call. The IBC indicator lights show normal sequence when the lights are on steady. When a problem occurs, the IBC ﬂashes combinations of lights which indicate the most likely reason for the problem.

While attempting to satisfy the heat demand, the control module monitors the boiler temperature changes via the temperature sensors and determines whether or not the available hot water will satisfy the demand, only running the circulator. If additional heat is needed, the sequence continues. When DHW (if used) calls for heat, sequence above is bypassed.

2 Transformer

The control transformer reduces line voltage to 24 volts for the gas valve and limit circuit.

LEGEND

a Supply to system, 1” NPT

b Return from system, 1” NPT

c Combustion air inlet ﬁtting —

3” PVC connection

d Flue outlet — 3” PVC connection

e Gas valve — negative pressure

regulated gas control

f Pressure/temperature gauge

3 Blower

The blower pulls in air and mixes it with gas from the gas valve. The blower forces this mixture into the burner for combustion inside the boiler chamber.

4 Recuperator

The recuperator is a stainless steel heat exchanger that increases boiler efﬁciency by extracting additional heat from the ﬂue gases. Return water passes through the recuperator before entering the boiler.

5 Water temperature sensor

The water temperature sensor provides a signal to the control module to turn off the gas valve if the temperature in the boiler goes above its setting. (The circulator will continue to run as long as there is a call for heat.)

6 System circulator

The system circulator circulates water through the external (system) piping. The ﬂow rate of the circulator is controlled by the IBC, depending on the temperature of the water entering the boiler sections. Pump must remain on boiler — do not remove.

7 Bypass circulator

The IBC operates the bypass circulator to mix hot water from the boiler outlet with colder return water from the system as needed to prevent condensation of ﬂue gases in the cast iron heat exchanger.

When the water returning to the boiler is below 140°F, the IBC regulates the bypass circulator and system circulator ﬂow rates to raise the return water temperature up to 140°F before it enters the cast iron sections. By balancing these ﬂow rates, the IBC can protect against condensation even if return water is as low as 60°F.

Pump must remain on boiler — do not remove.

g Flueway inspection port cover

h Sensor hose trap

i Manual air vent

j Relief valve

k Thermal fuse — a one-time fuse

device that shuts boiler off if ﬂue temperature exceeds its setpoint

m Condensate trap line — shipped

loose with boiler, ﬁeld installed

n Condensate drain connection —

½” PVC female

8 Air pressure switch

The air pressure switch signals the IBC, telling the control whether air is moving through the blower.

9 Return water temperature sensor

The water temperature sensor monitors the temperature of the water entering the boiler sections. The sensor sends this information to the IBC. The IBC determines how much to adjust the circulator ﬂow rates to provide at least 140°F water to the cast iron heat exchanger.

This boiler uses a negative-pressureregulated gas valve, set for an outlet pressure approximately –0.20” water column.

DO NOT set the outlet pressure higher

than factory setting.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

GWC Series 2 Water Boiler

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Contents

How it works . . . . . . . . . . . . . . 2

GWC Water Boiler . . . . . . . . . . 3

Please read before proceeding . . . 5

Prepare boiler location . . . . . . .6

Installations must follow these codes: . . . 6

High altitude installations. . . . . . . . . . 6

Residential garage installation . . . . . . . 7

Check oriﬁce plate — replace if necessary . 8

Install condensate trap. . . . . . . . . . . . 9

Install high altitude air pressure switch when

required (only above 5,500 feet) . . . . . 10

Rotate the boiler into position . . . . . . 10

Perform hydrostatic pressure test. . . . . 11

Install water piping . . . . . . . . 12

General piping information. . . . . . . . 12

Install relief valve . . . . . . . . . . . . . 12

Expansion tank. . . . . . . . . . . . . . . 13

System water piping methods. . . . . . . 15

Circulators . . . . . . . . . . . . . . . . . 15

Simpliﬁed pipe/circulator selection . . . 15 Baseboard system piping —

CIRCULATOR zoning (primary/secondary) 16

Baseboard system piping — ZONE VALVE zoning (direct connection) 16

Radiator system piping . . . . . . . . . . 18

Single-zone radiant heating or heat pump 19

Adjust balancing valves . . . . . . . . . . 19

Multi-zone radiant heating system . . . . 20

Piping snow melt systems or combination

snow melt/space heating systems . . . . . 21

Water chiller systems . . . . . . . . . . . 22

Multiple boiler installations . . . . 23

Placing multiple boilers . . . . . . . . . . 23

Controlling multiple GWC boilers . . . . 23

Piping multiple GWC boilers . . . . . . . 23

Multiple boiler water piping. . . . 24

Secondary header piping installation. . . 24

Venting & air — general. . . . . . 29

When removing a boiler from an existing

common vent system . . . . . . . . . . . 29

Existing vent test procedure. . . . . . . . 29

Provide combustion air:. . . . . . . . . . 30

Vent and air termination options. . . . . 30

DIRECT VENT installations . . . . . . . 30

DIRECT EXHAUST installations. . . . . 30

Combustion air contamination: . . . . . 30

Manifolded combustion air option for DIRECT VENT multiple boiler installations 31

Air manifold sizing . . . . . . . . . . . . 31

Commonwealth of Massachusetts

installations . . . . . . . . . . . . 34

Vent termination requirements . . 35

DIRECT VENT — Boiler room air

openings . . . . . . . . . . . . . . 36

DIRECT VENT — Sidewall with sepa-

rate pipes. . . . . . . . . . . . . . 37

DIRECT VENT — Sidewall with 3”

concentric . . . . . . . . . . . . . 39

DIRECT VENT — Vertical with sepa-

rate pipes. . . . . . . . . . . . . . 41

DIRECT VENT — Vertical with 3”

concentric . . . . . . . . . . . . . 43

Concentric termination assembly

(sidewall or vertical). . . . . . . . 45

Vent and air piping and boiler con-

nections . . . . . . . . . . . . . . 46

DIRECT EXHAUST & DIRECT VENT . 46

Follow termination instructions . . . . . 46

Installing vent and air piping . . . . . . . 46

DIRECT EXHAUST ONLY . . . . . . . . 46

DIRECT EXHAUST — Boiler room air

openings . . . . . . . . . . . . . . 47

Combustion air provision. . . . . . . . . 47

Sizing combustion air openings . . . . . 47

Special considerations . . . . . . . . . . . 47

GWC boiler WITHOUT other

appliances in room. . . . . . . . . . . . . 48

Air openings . . . . . . . . . . . . . . . . 48

GWC boiler WITH other

appliances in room. . . . . . . . . . . . . 48

DIRECT EXHAUST — Sidewall . . 49

DIRECT EXHAUST — Vertical. . . 51

Gas piping . . . . . . . . . . . . . 52

Connecting gas supply piping. . . . . . . 52

Natural Gas. . . . . . . . . . . . . . . . . 53

Propane Gas . . . . . . . . . . . . . . . . 53

Wiring . . . . . . . . . . . . . . . 53

Field wiring. . . . . . . . . . . . . . . . . 54

Start-up. . . . . . . . . . . . . . . 57

Freeze protection (when used) . . . . . . 57

Clean system to remove sediment . . . . 57

Water chemistry . . . . . . . . . . . . . . 57

Antifreeze. . . . . . . . . . . . . . . . . . 57

Fill and test water system . . . . . . . . . 58

Check for gas leaks. . . . . . . . . . . . . 59

Verify gas/air oriﬁce plate . . . . . . . . . 59

Check thermostat circuit(s) . . . . . . . . 59

Inspect/ﬁll condensate system . . . . . . 59

Final checks before starting boiler . . . . 60

Adjust boiler control settings . . . . . . . 60

Ajust boiler control settings. . . . . . . . 60

Boiler Economy settings. . . . . . . . . . 60

To start the boiler . . . . . . . . . . . . . 60

If boiler does not start correctly . . . . . 60

Check system and boiler after start-up. . 60 Gas valve adjustment — altitude

over 5,500 feet ONLY . . . . . . . . . . . 61

Final checklist . . . . . . . . . . . . . . . 62

Department of Energy Compliance . 63

IBC (Sequence of operations). . . . . . . 64

Operating Instrustions . . . . . . . . . . 65

Annual start-up and general mainte-

nance schedule . . . . . . . . . . 66

Annual start-up . . . . . . . . . . 67

Address reported problems. . . . . . . . . 67

Inspect boiler area . . . . . . . . . . . . . 67

Inspect boiler interior . . . . . . . . . . . 67

Inspect condensate drain system . . . . . 67

Inspect all piping for leaks . . . . . . . . 67

Inspect gas piping . . . . . . . . . . . . . 67

Inspect the water system. . . . . . . . . . 67

Check water system chemistry . . . . . . 67

Inspect expansion tank . . . . . . . . . . 68

Inspect air openings . . . . . . . . . . . . 68

Inspect vent system and air piping . . . . 68

Inspect boiler heating surfaces . . . . . . 68

Inspect igniter . . . . . . . . . . . . . . . 68

Inspect temperature mixing system . . . 69

Inspect additional controls and cutoffs. . . . 69

Inspect gauges . . . . . . . . . . . . . . . 69

Inspect blower motor . . . . . . . . . . . 69

Inspect oiled-bearing circulators . . . . . 69

Inspect temperature sensor . . . . . . . . 69

Inspect boiler relief valve . . . . . . . . . 70

To complete Annual Start-up, perform

startup and checks: . . . . . . . . . . . . 70

Review with owner. . . . . . . . . . . . . 70

Service & maintenance . . . . . 71

Cleaning boiler heating surfaces . . . . . 71

Inspecting and cleaning the recuperator . 72

Troubleshooting . . . . . . . . . 74

VERIFY PROPER OPERATION AFTER

SERVICING. . . . . . . . . . . . . . . . .

Before troubleshooting . . . . . . . . . . 74

Check the following . . . . . . . . . . . . 74

Checking the air pressure switch . . . . . 74

Igniter. . . . . . . . . . . . . . . . . . . . 75

Gas Valve . . . . . . . . . . . . . . . . . . 75

Blower Housing . . . . . . . . . . . . . . 75

Thermal fuse . . . . . . . . . . . . . . . . 75

Return temperature sensor . . . . . . . . 76

Supply temperature sensor . . . . . . . . 76

IBC (integrated boiler control) . . . . . . 77

IBC indicator lights — lockout modes . . 77 IBC indicator lights —

non-lockout modes . . . . . . . . . . . . 77

Replacement parts . . . . . . . . 88

Dimensions and ratings. . . . . . 99

Notes . . . . . . . . . . . . . . . 104

Handling ceramic ber and

berglass materials . . . . . . . 106

Installation and service

certicate . . . . . . . . . . . . 107

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Please read before proceeding

Hazard denitions

The following deﬁned terms are used throughout this manual to bring attention to the presence of hazards of various risk levels or to important information concerning the life of the product.

Indicates presence of hazards that will cause severe

personal injury, death or substantial property damage.

Indicates presence of hazards that can cause severe

personal injury, death or substantial property damage.

Indicates presence of hazards that will or can cause

minor personal injury or property damage.

Indicates special instructions on installation, op-

eration or maintenance that are important but not related to personal injury or property damage.

Installer— Read all instructions, including this

manual and all other information shipped with the boiler, before installing. Perform steps in the order given.

User — This manual is for use only by a qualiﬁed

heating installer/service technician. Refer to User’s Information Manual for your reference.

User — Have this boiler serviced/inspected by a

qualiﬁed service technician, at least annually.

Failure to comply with the above could result in

severe personal injury, death or substantial property damage.

Write in the CP number in the space provided on

the Installation certiﬁcate on page 107 if not already shown.

When calling or writing about the boiler— Please

have the boiler model number from the boiler rating label and the CP number from the boiler jacket.

Consider piping and installation when determining

boiler location.

Any claims for damage or shortage in shipment

must be ﬁled immediately against the transportation company by the consignee.

Commonwealth of Massachusetts

When the boiler is installed within the Commonwealth of Massachusetts, comply with the following.

• This product must be installed by a licensed plumber or gas ﬁtter.

• If antifreeze is used, a reduced pressure back-ﬂow preventer device shall be used.

• If sidewall vent or vent/air is installed, see instructions on page 34.

Failure to adhere to the guidelines on this

page can result in severe personal injury, death or substantial property damage.

When servicing boiler —

• To avoid electric shock, disconnect electrical supply before performing maintenance.

• To avoid severe burns, allow boiler to cool before performing maintenance.

• This boiler contains ceramic fiber and fiberglass materials. Refer to the WARNING and instructions on page 106.

Boiler operation —

• Do not block ﬂow of combustion or ventilation air to boiler.

•

Should overheating occur or gas supply fail to shut off, DO NOT turn off or disconnect electrical

supply to circulator. Instead, shut off the gas supply at a location external to the appliance.

•

Do not use this boiler if any part has been under water. Immediately call a qualiﬁed service techni-

cian to inspect the boiler and to replace any part of the control system and any gas control that has been under water.

Combustion air —

• DO NOT install combustion air intake where there

is a risk of combustion air contamination.

Carbon monoxide detector —

• For Direct Exhaust units, a carbon monoxide detector is required in the boiler room. The carbon monoxide detector must be wired on the same electrical circuit as the boiler.

• For

Boiler water —

• Thoroughly ﬂush the system (without boiler con-

• Do not use petroleum-based cleaning or sealing

•

Freeze protection uids —

• NEVER use automotive or standard glycol antifreeze.

Direct Vent units, a carbon monoxide detector that

is wired on the same electrical circuit as the boiler is strongly recommended.

nected) to remove sediment. The high-efﬁciency heat exchanger can be damaged by build-up or corrosion due to sediment.

compounds in boiler system. Gaskets and seals in the system may be damaged. This can result in substantial property damage.

Leaks in boiler or piping must be repaired at once to prevent make-up water. Use this boiler ONLY in a closed-loop system. Continual fresh make-up

water will reduce boiler life. Mineral buildup in heat exchangers reduces heat transfer, overheats the materials, and causes failure. Addition of oxygen carried in by make-up water can cause internal corrosion.

Do not add cold water to hot boiler. Thermal shock

can cause heat exchanger to crack.

Use only freeze-protection ﬂuids made for hydronic systems. Follow all guidelines given by the antifreeze manufacturer. Thoroughly clean and ﬂush any replacement boiler system that has used glycol before installing the new boiler.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Prepare boiler location

Installations must follow these codes:

• Local, state, provincial, national codes, laws, regulations and ordinances.

• NationalFuelGasCode,ANSIZ223.1-latestedition.

• StandardforControlsandSafetyDevicesforAutomaticallyFiredBoil-

ers, ANSI/ASME CSD-1, when required.

• NationalElectricalCode.

• ForCanadaonly:B149.1orB149.2InstallationCodeandCSAC22.1

Canadian Electrical Code Part 1 and any local codes.

The GWC boiler gas manifold and controls met safe lighting and other performance criteria when boiler underwent tests speciﬁed in ANSI Z21.13 — latest edition.

For the Commonwealth of Massachusetts, read and follow

the special instructions located on page 34 of this manual.

Install the boiler so control system components are protected

from dripping or spraying water or rain

Allowing these components to become wet could cause a boiler failure, resulting in severe personal injury, death or substantial property damage.

during operation.

High altitude installations

GWC boiler controls automatically reduce input with increasing altitude. See Figure 1 for estimated input at altitude as a percentage of sea level input. Multiply the boiler sea level input by this percentage to obtain the estimated high altitude input. Note that the length of the venting system will also have a minor impact on input.

Figure 1 Estimated GWC input at altitude

Altitude

(feet)

1,000 97 2,000 93 3,000 90 4,000 87 5,000 83 5,500 82 6,000 80 7,000 77 8,000 74 9,000 72

10,000 69

Figure 2 Service clearances (recommended)

% Sea level input

No modiﬁcations to the boiler should be necessary for installations up to 5,500 feet above sea level. For higher elevations, the air pressure switch must be changed to a special high altitude switch. Refer to the high altitude kit instructions, page 10. Note that the gas valve outlet pressure must be checked (and adjusted if necessary) following instructions on page 61.

DO NOT sidewall vent DIRECT EXHAUST APPLICATIONS

at altitudes above 5,500 feet. Sidewall venting is only allowed for DIRECT VENT applications (ducted combustion air) at altitudes above 5,500 feet.

Vent length also affects boiler input — the boiler automati-

cally derates to compensate for pressure loss through the vent. See the derate values given in Figure 106, page 100. For high altitude installations, multiply the % in Figure 1 times the value shown in Figure 106 to determine input vs sea level.

Service clearances

When possible, install GWC boilers with clearances at least as large as shown in Figure 2 for best service access.

Flooring

The GWC boiler is approved for installation on combustible ﬂooring, but must never be installed on carpeting.

Do not install boiler on carpeting even if foundation is used.

Fire can result, causing severe personal injury, death or substantial property damage.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Prepare boiler location (continued)

Foundation

Provide a solid brick or concrete foundation pad if any of the following is possible:

• When the ﬂoor can become ﬂooded.

• When the boiler mounting area is not level.

• When a high-proﬁle condensate pump is used, provide a foundation

high enough that the GWC condensate connection is at least as high as the condensate pump inlet connection.

Figure 3 Minimum foundation dimensions (inches)

Boiler model W L H *

GWC-070 GWC-105

GWC-140 GWC-175

* Increase height if needed to ensure condensate trap outlet tee is above inlet of condensate pump, when used.

16 30¾ 2

16 37¾ 2

Residential garage installation

Figure 4 Minimum clearances — when

clearances are less than recommended service clearances of Figure 2, page 6, install as shown below:

A Area adjacent to access door must be accessible

and must allow for removal of the GWC boiler for service. No other appliance or air mover (exhaust fan, etc.) may be mounted in the same space.

B Access DOOR with fresh air openings C Provide (2) Fresh air openings — Each with at

least 1 sq. inch per 1,000 Btuh of boiler input

Precautions

Take the following special precautions when installing the boiler in a residential garage. If the boiler is located in a residential garage, per ANSI Z223.1, paragraph 5.1.9:

• Mount the boiler a minimum of 18 inches above the oor of the garage to assure the burner and ignition devices will be no less than 18 inches above the ﬂoor.

• Locate or protect the boiler so it cannot be damaged by a moving vehicle.

Minimum clearances

You can install GWC boilers in spaces smaller than Fig-

ure 2, page 6 recommended service clearances, but never smaller than shown in Figure 4.

Installations with clearances less than shown in Fig-

ure 2, page 6 must have air openings sized and located as shown in Figure 4.

• Always provide at least screwdriver clearance to jacket front panel screws for removal of front panel for inspection and minor service.

• If the boiler and isolation valves so it can be slid out of the space and serviced in an adjacent area.

• The space has to be equipped with a door so boiler can be accessed, unpiped and removed.

cannot be serviced in place, pipe the boiler with unions

NOTICE SPECIAL REQUIREMENTS

FOR AIR OPENINGS

with clearances less than recommended service clearances (Figure 2, page 6), but

no less than shown in Figure 4 — An

access door must be provided, ﬁtted with two air openings as shown in Figure 4. Each opening must have a free area no less than 1 square inch per 1000 Btuh input of the GWC boiler in the space.

DO NOT apply the air opening sizes given in Figure 42, page 36 or Fig-

ure 56, page 48

: For installations

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Prepare the boiler (continued)

Check oriﬁce plate — replace if necessary

The correct orice plate must be used. Failure to do so

will result in severe personal injury, death or substantial property damage. The boiler is shipped with a natural

gas orice plate. It MUST BE CONVERTED to use propane.

Natural gas:

For natural gas installations, inspect the silver gas/air orice plate

marking

stamped with another size, obtain the correct plate from your wholesaler. The boiler size is stamped where the “X” is shown in the plate stamping, Figure 6.

Propane:

For propane installations, replace the silver gas/air orice plate with

the red/white plate

plate boiler size is correct for the GWC boiler being installed. The boiler size is stamped where the “X” is shown in the plate stamping, Figure 6.

Also ﬁll out the propane label in the conversion kit and attach to the left side of the jacket, above the gas inlet opening, as shown in Figure 5.

Orice plate installation, when required

Access the bottom of the blower housing as shown in Figure 5.

. It must be the same as the boiler size. If the oriﬁce plate is

, per following instructions. Ensure the red/white

Figure 5 Check for correct gas oriﬁce plate

A Remove jacket front

panel to access the bottom side of the blower housing.

B Complete the propane

conversion label included with the conversion kit. Install label on jacket left side, as shown.

Leave the boiler on its back, on the skid as shown, until you have checked the gas/air oriﬁce plate and replace it if necessary.

Figure 6 Follow instructions to check or replace

gas oriﬁce plate ("X" = boiler size)

To inspect the plate only,

read the marking on the plate edge. It

must read the same as the boiler size and fuel, as follows:

Boiler model Natural gas marking Propane marking

GWC-070 NG 3 SEC LP 3 SEC

GWC-105 NG 4 SEC LP 4 SEC

GWC-140 NG 5 SEC LP 5 SEC

GWC-175 NG 6 SEC LP 6 SEC

To replace the plate, using a manual screwdriver or nut driver, see Figure 6:

1. Loosen screws

2. Remove screws

1 and 2 two full turns.

3 and 4.

3. Pull the gas/air oriﬁce plate forward to remove it.

4. Slide in the new plate as shown in Figure 6. The

propane plate must go next to the blower housing

5. Replace screws

3 and 4. Tighten all four screws securely and uni-

red side of a

formly. DO NOT overtighten. DO NOT exceed 40 inch-pounds torque.

6. Bend down plate label tab at score mark as shown in lower right corner of Figure 6, item 10.

DO NOT use electric or pneumatic screwdrivers to re-

move or tighten the gas/air boss screws. Hand-tighten only, using manual screwdriver. Should the torque exceed 40 inch-pounds, the threaded holes could strip out, causing an inadequate seal of the oriﬁce plate. Failure to properly seal the plate to the housing could result in a gas leak, causing severe personal injury, death or substantial property damage.

1–4 Screws — follow instructions for loosening and tightening

5 Gas/air manifold 6 Front section, bottom view, component details omitted 7 Side shown must point toward air inlet hose — WARNING

label side for natural gas; WHITE side for propane gas

8 Propane oriﬁce plate, RED one side and WHITE on the

other (red side must face the blower housing

9 Natural gas oriﬁce plate, SILVER 10 Oriﬁce plate after bending along score mark — label is

visible when installed

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Prepare the boiler (continued)

Install condensate trap

1. Before placing the boiler in position, install the condensate trap line, shown in Figure 7. Items shown are provided with the boiler.

Step 1 Attach the ﬂue drain hose (C) to the in-line ﬂue drain

nipple (B).

Step 2 Slide a screw driver or pencil through the condensate

drain nipple (G).

Slide the end of the screwdriver or pencil into the open end of the ﬂue drain hose (C).

Feed the in-line ﬂue drain (A) assembly into the ﬂue connection (D), guiding the ﬂue drain hose through the condensate drain nipple (G) with the screwdriver or pencil.

Step 3 Press the in-line ﬂue drain (A) into the ﬂue connection

(D) and through the seal ring until it reaches the stop. Then tighten the ﬂue connection hose clamp to secure.

The ﬂue drain hose (C) should now extend down past the end of the condensate drain nipple (G).

Step 4 Slide the U-clamp (F) over the condensate trap tee (E)

and into the two holes in the rail. Attach the two nuts provided to the U-clamp and tighten to secure the condensate trap tee to the rail.

Step 5 Slide the ends of the condensate trap hose (H) onto the

condensate drain nipple (G) and the condensate trap tee (E). Secure the condensate trap hose at each end with the hose clamps (J).

Check the height of the condensate trap tee outlet.

Before rotating the boiler into position, measure the distance from the condensate tee outlet to the bottom of the boiler mounting rails. When the boiler is place in position, the condensate tee outlet must be higher than the condensate pump inlet connection (when a condensate pump is used). Increase the foundation height if necessary.

Figure 7 Install condensate trap

A In-line ﬂue drain B Flue drain nipple C Flue drain hose D Flue connection E Condensate trap tee F U-clamp and nuts (not

shown)

G Condensate drain

nipple

H Condensate trap hose J Hose clamps

Finished assembly

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Prepare the boiler (continued)

Install high altitude air pressure switch when required (only above 5,500 feet)

1. For installations at altitude more than 5,500 feet above sea level: a. A special high altitude air pressure switch is required. b. The gas valve outlet pressure setting must be checked, and

adjusted if necessary, per the instructions on page 61.

Failure to check gas valve outlet pressure and adjust, if

necessary, could result in severe personal injury, death or substantial property damage. Carefully follow the guidelines given in this manual.

2. Obtain the GWC high altitude kit from your local WilliamsonThermoﬂo distributor. The high altitude kit contains the high altitude air pressure switch.

3. See Figure 8 (switch shown with wires removed). a. Remove the two (RED) control wires from the air pressure

switch spade terminals.

b. Remove the factory-installed air pressure switch (loosen top

screw and remove bottom screw holding switch to jacket interior panel).

c. Install the high altitude air pressure switch in the same loca-

tion.

d. Carefully replace the hoses on the new switch, with the red hose

on the hose barb closest to the electrical spade connectors, as shown in Figure 8. The white hose goes on the other hose barb.

e. Replace the two (RED) control wires on the new pressure

switch spade terminals.

Figure 8 Air pressure switch mounting

1 Interior panel top 2 Jacket left side panel 3 Air pressure switch

4 WHITE hose 5 RED hose

6 Mounting screws

Figure 9 Follow instructions to perform the steps

shown below

Rotate the boiler into position

Boiler is shipped on back side. It must be taken off skid

and rotated into correct position.

After installing condensate line, inspecting (replacing if necessary) the gas/air oriﬁce and installing the high altitude kit (if required), move the boiler near its position.

Figure 9 shows the boiler with the front and top panels replaced. These panels may be left off if desired until the installation has been completed.

Boiler is heavy and contains some sheet metal parts which

may have sharp edges. Wear gloves when handling and take proper precautions when moving. Failure to do so will result in severe personal injury, death or substantial

property damage.

Refer to Figure 9 for placement sequence as follows:

1 Wear heavy gloves — carefully rotate the boiler over onto its

base rail legs.

2 Clip the shipping strap securing the skid to the boiler block as-

sembly. Remove the skid and strap.

3 Attach the jacket rear panel as shown using (4) #10 x ½” screws

provided in the accessory bag.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Prepare the boiler (continued)

Perform hydrostatic pressure test

Pressure test boiler before attaching water or gas piping (except as noted below) or electrical supply. Remove jacket top panel before proceeding.

Use two wrenches when tightening water piping at

boiler

, using one of the wrenches to prevent the boiler interior piping from turning. Failure to support the boiler piping connections to prevent them from turning could cause damage to boiler components.

Prepare boiler for test — see Figure 10

Step 1 Connect a hose from water supply to ﬁll and drain boiler

for hydrostatic test. Hose is not included with boiler.

Step 2 Connect hose to boiler drain valve. Make sure hose can

also be used to drain boiler after test.

Step 3 Remove 1" nipple, 1" tee, bushing and pressure/tempera-

ture gauge from accessory bag. Pipe to boiler supply connection as shown. Use pipe dope sparingly.

Step 4 Connect a nipple and shutoff valve to system supply

connection on the 1" tee. This valve will be used to bleed air during the ﬁll. Valve and nipple are not included with boiler.

Step 5 Connect a nipple and shutoff valve to system return

connection at circulator ﬂange. This valve will be used to bleed air during the ﬁll. Valve and nipple are not included with boiler.

Figure 10 Piping connections for hydrostatic test

Step 6 Install a ¾" pipe plug in the relief valve opening, top of

the rear boiler section, as shown. Plug is not included with boiler.

Fill and pressure test

1. Connect ﬁll water supply through drain valve, item 2.

2. Fill boiler with water (be sure bleed valves at 4 and 5 are open).

3. When water flows from bleed valves, shut off water at drain valve.

4. Close bleed valves.

5. Slowly reopen drain valve (item 2) until test pressure of 45 PSIG (or 1.5 times boiler relief valve setting — NEVER MORE than 75 PSIG) is reached on the pressure gauge.

6. Test at this pressure for no more than 10 minutes.

Do not leave boiler unattended. If the boiler is ﬁlled with

cold water, the water can absorb heat from the room and expand, causing excessive pressure, resulting in severe personal injury, death or substantial property damage.

7. Make sure constant gauge pressure has been maintained throughout test. Check for leaks. Repair if found.

Leaks must be repaired at once. Failure to do so can

damage boiler, resulting in substantial property damage.

Do not use petroleum-based cleaning or sealing com-

pounds in boiler system. Severe damage to boiler will occur, resulting in substantial property damage.

Drain and remove ttings

1. Disconnect ﬁll water hose from water source.

2. Drain boiler at drain valve or out hose, whichever provides best access to drain. Close drain valve and remove hose after draining.

3. Remove plug (item 6) from relief valve tapping.

4. Isolation valves are required to enable servicing of the boiler’s temperature sensor.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Install water piping

Use two wrenches when tightening water piping at

boiler

, using one of the wrenches to prevent the boiler interior piping from turning. Failure to support the boiler piping connections to prevent them from turning could cause damage to boiler components.

The cast iron heat exchanger return temperature must

be kept at or above 140°F during all times of operation to prevent possibility of corrosion due to condensation. This is done automatically, using the boiler's internal circulators. DO NOT remove or tamper with these circulators. Failure to comply could result in severe personal injury, death or substantial property damage.

General piping information

Minimum pipe size for boiler loop piping

Figure 11 Provide boiler loop piping no smaller than listed

below (based on 20°F temperature rise)

Boiler loop pipe size, Minimum

GWC-070 or 105 1”

GWC-140 or 175 1¼”

Additional limit controls

Following standard industry practices, if installation is to comply with ASME or Canadian requirements, an additional high temperature

limit

may be needed. Consult local requirements for other codes/

standards to determine if needed. Wire as shown in Figure 63, page 54.

• Install a manual reset high temperature limit between the boiler and the isolation valve.

• Wire the manual reset limit in series with the boiler limit control.

• Set the manual reset limit control at least 20°F above the boiler limit control setting (maximum setting 220°F).

Air separator

Install an air separator in the piping as shown in this manual. For single-zone systems, install the air separator in the return piping as shown in Figure 14, page 14. This allows mounting the automatic air vent and expansion tank off of the separator.

Install relief valve

1. Install relief valve ONLY as shown in Figure 12.

2. Connect discharge piping to safe disposal location, following guidelines in Figure 13, page 13.

Figure 12

Install and pipe relief valve

Low water cut-off, when required

A low water cutoff device is required when boiler is installed above radiation level or by certain state or local codes or insurance companies. Use low water cutoff designed for water installations. Electrode probetype is recommended. Purchase and install in tee in supply piping above boiler. Wire contact as shown in Figure 63, page 54.

If boiler is connected to heating coils located in air han-

dling units where they can be exposed to refrigerated air, use ﬂow control valves or other automatic means to prevent gravity circulation during cooling cycle. Circulation of cold water through the boiler could result in damage to the heat exchanger, causing possible severe personal injury, death or substantial property damage.

Backow preventer

Where required by codes, install a backow preventer in the cold water ﬁll line, as shown in suggested piping diagrams on following pages. Install a check valve if a backﬂow preventer is not installed.

Legend

1 Jacket plug for unused relief valve jacket open-

ing.

2 Jackets are provided with two relief valve open-

ings because each jacket size is used for two boiler sizes. Cover the unused opening with the plug

provided. 3 Boiler relief valve (from accessory bag) 4 ¾” x 3” nipple, provided in accessory bag 5 ¾” relief valve tapping in back section 6 Connect minimum ¾” discharge piping to relief

valve.

See Figure 13, page 13.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Install water piping (continued)

Figure 13 Relief valve installation guidelines

To avoid water damage or scalding

due to relief valve operation, as per local or state codes

Discharge line must be connected

to relief valve outlet and run to a safe place of disposal. Terminate the discharge line in a manner that will prevent possibility of severe burns or property damage should the valve discharge.

Discharge line must be as short as

possible and be the same size as the valve discharge connection throughout its entire length.

Discharge line must pitch downward

from the valve and terminate at least 6” above the ﬂoor drain where any discharge will be clearly visible.

The discharge line shall terminate

plain, not threaded, with a material serviceable for temperatures of 375°F or greater.

Do not pipe the discharge to any

place where freezing could occur.

Expansion tank

Figure 14, page 14 and Figure 15, page 14 show typical installation of the expansion tank. Always locate the air separator and expansion tank as shown in the suggested piping drawings, beginning with Figure 17, page 16.

Ensure that the expansion tank size will handle boiler and system water volume and temperature. See tank manufacturer’s instructions and ratings for details. Additional tanks may be added to the system if needed to handle the expansion. These tanks may be installed by connecting to tees in the system piping.

Undersized expansion tanks cause system water to be lost

from the relief valve and makeup water to be added through the ﬁll valve. Eventual section failure can result. Always locate the cold water ll connection at the expansion tank. Never locate this elsewhere in the system.

Diaphragm- or bladder-type tank:

Refer to Figure 14, page 14 for suggested piping when using a diaphragmor bladder-type expansion tank.

Diaphragm- or bladder-type expansion tank — Control

ll pressure with the tank air charge pressure. Always check

pressure and charge tank with tank removed from system to be sure reading is accurate. Boiler relief valve is set for 30 PSIG. Operating pressure of system, after temperature expansion above cold ﬁll pressure, should not exceed 24 PSIG to avoid weeping of relief valve.

Install an manufacturer’s instructions.

Closed-type expansion tank:

Figure 15, page 14 shows suggested piping when using a closed-type expansion tank, in which the air is directly in contact with tank water.

automatic air vent on top of the air separator, per separator

No shutoff valve shall be installed

between the relief valve and boiler, or in the discharge line. Do not plug or place any obstruction in the discharge line.

Test the operation of the valve after

ﬁlling and pressurizing system by lifting the lever. Make sure the valve discharges freely. If the valve fails to operate correctly, replace it with a new relief valve.

Failure to comply with the above

guidelines could result in failure of the relief valve to operate, resulting in possibility of severe personal injury, death or substantial property damage.

Part number 550-142-786/0712

Connect piping (½” or ¾”) from the air separator top outlet to the tank ﬁtting. Slope any horizontal piping a minimum of 1 inch per 5 feet of horizontal pipe.

Always use a (shown). The ﬁtting reduces gravity ﬂow of water in the piping to the tank, avoids air bubbling through the tank water, and provides the proper ﬁll height in the tank.

tank tting, such as the B&G Tanktrol or Taco Taco-Trol

Correct all leaks in the system or tank piping. Leaks allow

air to escape from the system and will cause water-logging of the tank. This will result in water loss through the boiler relief valve due to over-pressurization.

NEVER use an automatic air vent in a system equipped with a

closed-type expansion tank. The air removed from the system will cause water-logging of the expansion tank.

Closed-type expansion tank — Follow tank manufacturer’s

instructions for lling the tank. Typical tank sizing provides for approximately 12 PSIG when the tank is ﬁlled to the normal level and system water is cold. Note that boiler relief valve is set for 30 PSIG. Operating pressure of system, after temperature expansion above cold ﬁll pressure, should not exceed 24 PSIG to avoid weeping of relief valve.

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Install water piping (continued)

Figure 14 Piping to single-zone system using diaphragm- or

bladder-type expansion tank. Boiler connections are 1” NPT (supply from 1” tee, return to 1” recuperator ﬂange).

Figure 15 Piping closed-type expansion tank

Pipe diaphragm- or bladder-type expansion tanks to the bot-

tom of the separator.

Pipe closed-type (air in contact with water) tanks to the top of

the air separator. Always connect the ﬁll line to the expansion tank location, as shown above and in the suggested piping.

1 Relief valve discharge piping — see page 12 2 Isolation valves 3 Fill valve 4 Diaphragm-type expansion tank — always locate as

shown in the suggested piping drawings in this manual

5 Air separator

• provide with automatic air vent ONLY when used with diaphragm-type expansion tanks

• pipe air outlet to expansion tank when used with close-type tanks

Legend

6 Cold ﬁll line, with backﬂow preventer or check valve

when required by codes (see Figure 15 for typical components)

7 System supply piping 8 System return piping 10 Pressure reducing valve, when used 11 Quick-ﬁll bypass valve, when used 12 Closed-type expansion tank — always locate as shown

in the suggested piping drawings in this manual

13 Tank ﬁtting

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Install water piping (continued)

System water piping methods

Most piping methods shown in this manual use

primary/secondary connection to the boiler loop. These designs ensure proper ﬂow through the GWC boiler, for the most efﬁcient and reliable operation of the boiler and the heating system. For other piping methods, consult your local WilliamsonThermoﬂo representative.

Circulators

Do not remove either of the GWC internal pumps

for use elsewhere in the system. Both pumps are required for proper operation. Removing a pump will cause the boiler to malfunction. Substantial property damage could result.

Failure to comply could result in unreliable perfor-

Circulator ow rate

Size system circulators based on the ﬂow rate required to achieve the temperature change needed. You can closely estimate temperature rise (or drop) through a circuit by using the following formula, where TD is temperature rise (or drop), FLOW is ﬂow rate (in gpm), and BTUH is the heat load for the circuit:

Examples:

Consider a system loop for a system with total heating load equal to 210,000 Btuh. The desired temperature drop through the system piping is 20°F. Then the required ﬂow rate is:

FLOW =

SIMPLIFIED: For 20° temperature drop, FLOW = MBH / 10.

Circulator head requirement

The circulator must be capable of delivering the required ﬂow against the head loss that will occur in the piping. Determine the pipe size needed and the resultant head loss using accepted engineering methods. The simpliﬁed pipe sizing here is limited to residential systems, and does not include systems with fan coil units or radiant tubing.

Never install another pump in series with the GWC boiler

. Forced ﬂow can cause improper operation of the boiler controls. Substantial property damage could result.

mance and nuisance shutdowns from insufﬁcient ﬂow.

BTUH

FLOW =

—–—–—–—–

TD x 500

210,000

—–—–—–—–

= 21 gpm

20 x 500

The following simpliﬁed method for pipe and cir-

culator sizing must be limited to residential applications using baseboard (ﬁnned or cast iron), cast iron radiators or convectors. DO NOT apply for radiant heating, fan coil units or commercial installations.

Simpliﬁed pipe/circulator selection

1. Install the boiler and piping using the recommended piping layouts in this manual.

2. Size the piping and components for each circuit in the space heating system using Figure 16.

head loss in all piping will be 0.04 feet per foot of pipe.

a. Determine the heating load (Btuh) for each circuit. b. Calculate the ﬂow rate for each circuit using its load. To use a 20°F temperature drop, just divide the

MBH (1,000’s of Btuh) by 10. Example — Flow for 20°F temp drop with 35,000 Btuh: FLOW = 35 MBH / 10 = 3.5 gpm

c. Find the pipe size in Figure 16 that has a max ﬂow rate

just larger than that required for the circuit. d. Find the total equivalent length (TEL) of the circuit. TEL accounts for losses through ﬁttings and valves by

using the equivalent length of pipe that would cause

the same head loss. Add these numbers to the measured

length of the circuit to ﬁnd TEL in feet. TEL is usually close to 1.5 times the length of the

circuit for residential baseboard, radiator or convec-

tor applications.

e. Measure the length of each circuit from the circulator

outlet back to its inlet. Then multiply this length times

1.5 to get the approximate TEL of the circuit.

f. Find the head loss for each circuit:

TEL = 1.5 X Circuit Length (feet) HEAD = TEL X 0.04 (feet water column)

g. NOTE: Size system header piping for the total ﬂow of

all connected zones.

3. Example: a. For a circuit with heating load = 45,000 Btuh (= 45

MBH). Measured length of circuit is 88 feet. b. Flow = 45 MBH / 10 = 4.5 gpm. c. TEL = 1.5 x 88 feet = 132 feet. d. From Figure 16, select 1" pipe (max ﬂow = 8 gpm). e. Head loss = TEL x 0.04 = 132 x 0.04 = 5.28 feet. f. Select a circulator that can deliver at least 4.5 gpm at a

head of 5.28 feet. (Read the NOTICE below.)

To use this method, limit the ﬂow through ¾"

ﬁnned-tube baseboard to 3.9 gpm, or use 1" baseboard and limit ﬂow to 7.1 gpm. If the total load of the circuit requires more ﬂow, split the circuit into two or more.

Figure 16

Pipe size

(inches)

Flow rates for 0.04 feet head loss per foot of

copper pipe

MAX Flow rate (GPM)

@ 0.04 feet per foot

1¼

1½

(based on water at140°F)

At the ow rates listed, the

Pipe size

(inches)

2½

MAX Flow rate (GPM)

@ 0.04 feet per foot

140

290

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Install water piping (continued)

Baseboard system piping — CIRCULATOR zoning (primary/secondary)

Apply Figure 17 for circulator zoning on systems using baseboard heaters. The heaters can be any baseboard style, including ﬁnned tube or cast iron.

Zoning with circulators — The GWC internal system

circulator cannot be removed from the boiler for use as one of the zone circulators. It must remain as shipped from the factory to allow proper ﬂow control inside the boiler. You will need a circulator for each zone. Provide circulator relays or circulator zone controller.

Baseboard system piping — ZONE VALVE zoning (direct connection)

The boiler internal circulator can be used to circulate many zone-valve zoned systems as shown in Figure 18, page 17 for application on systems using baseboard (ﬁnned tube or cast iron).

• DO NOT apply this piping when using a GWC-175 — the internal

circulator cannot supply enough ow to the system

• When applying Figure 18, page 17, DO NOT exceed the limits

shown in Figure 19, page 17

• For systems requiring higher ow or head loss, apply the

suggested piping of Figure 20, page 18, NOT that of Figure 18, page 17.

Balancing, when required

—

Substitute a memory-stop valve for one of the isolation valves in each zone to use the memory-stop valve for balancing ﬂow as well as isolation.

Figure 17 Baseboard system — circulator zoning

MINIMUM

Boiler loop pipe size

GWC-070/105 GWC-140/1751”1¼”

Zoning with zone valves —

Provide a separate 24-volt transformer to power the zone valves. Size the transformer to handle the total rated load of all connected zone valves. Alternatively, use a zone valve zone controller.

Do not use R & C connections for zone valve.

DO NOT connect directly from 3-wire zone valves

to the T-T terminals on the boiler

. When using 3-wire zone valves, install an isolation relay. Connect the zone valve end switch wires to the isolation relay coil. Connect the isolation relay contact across the boiler T-T terminals. Failure to comply can result in damage to boiler components or cause unreliable operation, resulting in severe property damage.

Applying Figure 18, page 17

1. Figure 18, page 17 and Figure 19, page 17 provide guidelines for checking whether the GWC internal circulator can provide sufﬁcient ﬂow when directly connected to a two-pipe baseboard system.

The outputs of GWC boilers are all too high for con-

nection to a single-loop series-loop system. To apply to an existing series loop system, the system must be ﬁtted with trunk lines to convert to a split-loop system. Provide either one or two trunk lines to meet the minimum number of circuits and maximum loading per circuit given in Figure 19, page 17.

2. The system pipe sizing must be no smaller than shown in the Legend for Figure 18, page 17.

3. Values shown for maximum circuit lengths, maximum load per circuit and the maximum feet baseboard per circuit are limits that ensure the internal circulator will have sufﬁcient head to provide the ﬂow needed for each circuit.

Legend

1 Isolation valves

2 Automatic air vent (with

diaphragm-type expansion tank), or connect to tank ﬁtting (closed-type expansion tank).

3 Diaphragm- or bladder-

type expansion tank, if used. (For closed-type expansion tank, pipe from top of air separa-

tor to tank ﬁtting as in Figure 15, page 14.)

5 Zone circulator

6 Flow/check valve

7 Hose bibb purge valve

8 Boiler pressure/tempera-

ture gauge

16 Cold water ﬁll line — see

Figure 15, page 14 for typical components

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Install water piping (continued)

Figure 18 Zone valve zoning — GWC-070, GWC-105 or

GWC-140 (DO NOT apply to GWC-175)

Legend

1 Isolation valves

2 Automatic air vent (with

diaphragm-type expansion tank), or connect to tank ﬁtting (closed-type expansion tank).

3 Diaphragm- or bladder-

type expansion tank, if used. (For closed-type expansion tank, pipe from top of air separator to tank fitting as in Figure 15, page 14.)

4 Zone valve

7 Hose bibb purge valve

8 Boiler pressure/tempera-

ture gauge

10 Differential pressure by-

pass valve

16 Cold water ﬁll line — see

Figure 15, page 14 for typical components

Pipe sizes (NPT), minimum

Boiler model

GWC-070 GWC-105

GWC-140 1¼" ¾"

Mains

1" ¾"

Circuit requirements

See Figure 19

Circuits

One-pipe diverter tees systems

— The application information on this page is based on two-pipe baseboard systems.

whether the internal circulator can provide sufficient flow to a one-pipe diverter tee system, use the available head value given in Figure 19, page 17.

Figure 19 The system must meet the following requirements when applying Figure 18

Boiler

model

GWC-070

GWC-105

GWC-140

GWC-175 DO NOT apply to GWC-175 — Use primary/secondary piping ONLY, as in Figure 20, page 18.

* This application may be marginal. It could cause temperature distribution problems, because the temperature drop is 30°F,

NOT 20°F. The best method is to use primary/secondary piping for the GWC-140 as in Figure 20, page 18.

Circulator HEAD

available to the

system

6.4 feet w.c. @ 6.5 GPM

4.1 feet w.c. @ 9.7 GPM

5.5 feet w.c.

@8.7 GPM

Maximum

circuit length

103 feet 2 40 MBH 67 feet

92 feet 3 33 MBH 55 feet

112 feet 3 53 MBH 88 feet

Minimum

number

of circuits

Max load

of any circuit

Max feet baseboard

of any circuit

(@ 600 Btuh/foot)

Summary

6.5 GPM total

(max 4GPM any cricuit)

20°F temperature drop

9.7 GPM total

(max 3.3 GPM any circuit)

20°F temperature drop

8.7 GPM

(max 3.5 GPM any circuit)

30°F temperature drop

To check

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Install water piping (continued)

Radiator system piping

Apply Figure 20 (zone-valve zoning) or Figure 21 (circulator zoning) to systems using standing cast iron radiators. This applies to gravity water systems and converted steam systems using columnar, tubular or recessed cast iron radiators.

The suggested piping for zone-valve zoning radiator systems differs from baseboard systems because of the high water content of cast iron radiators. The GWC internal circulators automatically regulate supply and internal bypass ﬂow based on the temperature of the water returning to the boiler. At the start of many heating cycles in a radiator system, the water in the radiators is cool. So the boiler would slow down system ﬂow rate while sending out relatively hot water. This could cause heat distribution problems. Install a separate system circulator as shown in Figure 20 when zoning with zone valves. The separate circulator assures a relatively constant temperature drop through the system.

The boiler internal circulators must be left in the boiler. They cannot be removed for use a zoning circulator. Provide a circulator for each zone when circulator zoning, and pipe the system as in Figure 21.

Balancing, when required

valve for one of the isolation valves in each zone to use the memory-stop valve for balancing ﬂow as well as isolation.

Zoning with zone valves —

transformer to power the zone valves. Size the transformer to handle the total rated load of all connected zone valves. Alternatively, use a zone valve zone controller.

Do not use R & C connections for zone valve.

Zoning with circulators — The GWC internal system

—

Substitute a memory-stop

Provide a separate 24-volt

Figure 20 Radiator system — zone-valve zoning

(Optional)

MINIMUM

Boiler loop pipe size

GWC-070/105 GWC-140/1751”1¼”

Figure 21 Radiator system — circulator zoning

The system circulator must be supplied by the in-

staller.

Legend

1 Isolation valves 2 Automatic air vent (with diaphragm-type expansion tank), or

connect to tank ﬁtting (closed-type expansion tank).

3 Diaphragm- or bladder-type expansion tank, if used. (For closed-

type expansion tank, pipe from top of air separator to tank ﬁtting

as in Figure 15, page 14.) 4 Zone valve 5 System or zone circulator 6 Flow/check valve 7 Hose bibb purge valve 8 Boiler pressure/temperature gauge 9 System supply temperature gauge 10 Differential pressure by-pass valve 16 Cold water ﬁll line — see Figure 15, page 14 for typical components

MINIMUM

Boiler loop pipe size

GWC-070/105 GWC-140/1751”1¼”

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Install water piping (continued)

Single-zone radiant heating or heat pump

Radiant heating systems and heat pump systems usually require system supply water temperatures below 140°F. But the boiler outlet water temperature will be at least 150°F to 160°F during most operating conditions. So the piping must include a method of reducing the supply water temperature to the system.

Figure 22 uses two balancing valves to manually adjust the supply water temperature. Follow the instructions below to adjust these valves. Install the supply temperature limit control (item 14) as shown to protect the system from over-temperature conditions. Note also that this piping requires a separate system circulator, as shown, because of the higher ﬂow rates of radiant and heat pump systems.

Manual adjustment of the supply temperature is limited to singlezone systems because multi-zone systems will cause varying loads, making it unlikely an acceptable valve setting could be found. See Figure 23, page 20 or Figure 24, page 20 for multi-zone systems.

You may also apply the suggested piping of either Figure 23, page 20 or Figure 24, page 20 if you want automatic supply temperature regulation or outdoor reset temperature control.

For additional information and alternatives in piping for radiant heating systems, contact Williamson-Thermoﬂo.

Figure 22 Single-zone radiant heating or

heat pump system

MINIMUM

Boiler loop pipe size

GWC-070/105 GWC-140/1751”1¼”

The system circulator must be supplied by the in-

staller.

Adjust balancing valves

Use valves 17 and 18 to mix boiler supply water with system return water, reducing supply water temperature to the system.

1. Subtract the design system supply temperature from 150°F. Call this number the

temperature difference.

2. Open valve 17 and close valve 18.

3. Start the boiler and system.

4. Let the system warm up for about 15 minutes.

5. Note the temperature at gauge 9 (system supply) and gauge 8 (boiler supply).

6. Slowly close valve 17 while opening valve 18 until gauge 9 reads

lower than gauge 8 by at least the temperature difference found

in step 1.

7. Example: For a design supply temperature of 100°F, the

ture difference

would be 150°F minus 100°F, or 50°F. Set the valves

tempera-

until gauge 9 reads at least 50°F lower than gauge 8.

Legend

1 Isolation valves

2 Automatic air vent (with diaphragm-type expansion

tank), or connect to tank ﬁtting (closed-type expansion tank).

3 Diaphragm- or bladder-type expansion tank, if used

(For closed-type expansion tank, pipe from top of air separator to tank ﬁtting as in Figure 15, page 14.)

5 System circulator

7 Hose bibb purge valve

8 Boiler pressure/temperature gauge

9 System supply temperature gauge

10 Return temperature gauge

14 Supply temperature limit control — Set at a tempera-

ture below the maximum allowed for the system or as directed by the system designer.

16 Cold water ﬁll line — see Figure 15, page 14 for typical

components

17 Balancing valve

18 Balancing valve

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Install water piping (continued)

Multi-zone radiant heating system

Multi-zone systems require automatic regulation of the system supply temperature because of widely varying load conditions. Figure 23 (zone-valve zoning) and Figure 24 (circulator zoning) show suggested piping for these systems.

Provide an automatic temperature control valve or

motor-operated valve which can be adjusted for the desired supply water temperature. This is required to protect the radiant system from excessive temperature.

Zone-valve zoning — The suggested piping uses a separate circulator for system circulation to provide the higher ﬂow typical of radiant heating systems and to assure good temperature distribution in the system when the return water temperature is low.

Circulator zoning — The GWC internal circulators must not be removed. Provide a separate circulator for each zone.

Balancing, when required

valve for one of the isolation valves in each zone to use the memory-stop valve for balancing ﬂow as well as isolation.

Zoning with zone valves —

transformer to power the zone valves. Size the transformer to handle the total rated load of all connected zone valves. Alternatively, use a zone valve zone controller.

Do not use R & C connections for zone valve.

Zoning with circulators — The GWC internal system

tem circulator must be supplied by the installer.

Outdoor reset

Apply Figure 23 or Figure 24 for any system intended for outdoor reset of the supply water temperature. Use a motor-operated three-way valve and an outdoor reset temperature control system.

—

Substitute a memory-stop

Provide a separate 24-volt

Figure 23 Auto system supply temp regulation —

zone valve zoning

MINIMUM

Boiler loop pipe size

GWC-070/105 GWC-140/1751”1¼”

Figure 24 Auto system supply temp regulation —

circulator zoning

Legend

1 Isolation valves 2 Automatic air vent (with diaphragm-type expansion tank), or

connect to tank ﬁtting (closed-type expansion tank).

3 Diaphragm- or bladder-type expansion tank, if used (For closed-

type expansion tank, pipe from top of air separator to tank ﬁtting

as in Figure 15, page 14.) 4 Zone valve 5 System or zone circulator 6 Flow/check valve 7 Hose bibb purge valve 8 Boiler pressure/temperature gauge 9 System supply temperature gauge 10 Supply temperature automatic mixing valve 11 Differential pressure by-pass valve 16 Cold water ﬁll line — see Figure 15, page 14 for typical components

MINIMUM

Boiler loop pipe size

GWC-070/105 GWC-140/1751”1¼”

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Install water piping (continued)

Piping snow melt systems or combination snow melt/space heating systems

Combination snow melt/space heating systems can have return water temperature below 60°F, and the return temperature will ﬂuctuate. So these systems require automatic return water temperature as shown in Figure 25 (zone-valve zoning) or Figure 26 (circulator zoning).

Select an automatic temperature control valve or motor-operated valve which can be adjusted to provide a return water temperature of at least 60°F. Any setting higher than 60°F will also be acceptable.

Zone-valve zoning — The suggested piping uses a separate circulator for system circulation to assure good temperature distribution in the system when the return water temperature is low.

Circulator zoning — The GWC internal circulators must not be removed. Provide a separate circulator for each zone.

The return water temperature to the boiler must be

at least 60°F. Provide and apply means to regulate the return temperature. Failure to do so can result in boiler control operation problems, causing possible signiﬁcant property damage.

Zoning with zone valves

diagrams in this section is shown with an isolation valve on each side. Substitute a memory-stop valve for one of these in each zone in order to use the memory-stop valve for balancing ﬂow as well as isolation.

Provide a separate 24-volt transformer to power the zone

valves. Size the transformer to handle the total rated load of all connected zone valves.

Do not use R & C connections for zone valve.

Zoning with circulators — The GWC internal system

tem circulator must be supplied by the installer.

— Each zone in the piping

Figure 25 Auto return temp regulation — circulator

zoning

MINIMUM

Boiler loop pipe size

GWC-070/105 GWC-140/1751”1¼”

Figure 26 Auto return temp regulation — zone valve

zoning

Legend

1 Isolation valves 2 Automatic air vent (with diaphragm-type expansion tank), or

connect to tank ﬁtting (closed-type expansion tank).

3 Diaphragm- or bladder-type expansion tank, if used (For closed-

type expansion tank, pipe from top of air separator to tank ﬁtting

as in Figure 15, page 14.) 4 Zone valve 5 System or zone circulator 6 Flow/check valve 7 Hose bibb purge valve 8 Boiler pressure/temperature gauge 9 System supply temperature gauge 10 Return temperature automatic mixing valve 11 Differential pressure by-pass valve 16 Cold water ﬁll line — see Figure 15, page 14 for typical components

Part number 550-142-786/0712

MINIMUM

Boiler loop pipe size

GWC-070/105 GWC-140/1751”1¼”

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Install water piping (continued)

Water chiller systems

Pipe the boiler and water chiller as shown in Figure 27.

Install boiler, as shown, so chilled medium is piped in parallel with heating boiler.

Use appropriate valves to prevent chilled medium from entering boiler. See Figure 27 for typical installation of balancing valve and check valve.

Install the ﬂow/check valve in the boiler supply piping, as shown in Figure 27, to prevent gravity circulation during the cooling cycle.

If boiler is connected to heating coils located in air handling units where they can be exposed to refrigerated air, use ﬂow control valves or other automatic means to prevent gravity circulation during cooling cycle.

Balancing, when required

valve for one of the isolation valves in each zone to use the memory-stop valve for balancing ﬂow as well as isolation.

Zoning with zone valves —

transformer to power the zone valves. Size the transformer to handle the total rated load of all connected zone valves. Alternatively, use a zone valve zone controller.

Do not use R & C connections for zone valve.

Zoning with circulators — The GWC internal system

—

Substitute a memory-stop

Provide a separate 24-volt

Figure 27 Installing GWC boiler in system with water

chiller

MINIMUM

Boiler loop pipe size

GWC-070/105 GWC-140/1751”1¼”

Chilled water systems often use closed-type expansion

tanks, as shown in Figure 27. DO NOT install automatic air vents on these systems.

Legend

1 Isolation valves

2 Air separator

3 Expansion tank with tank ﬁtting (piping shown for

application of a closed-type expansion tank)

5 System circulator

6 Flow/check valve

8 Boiler pressure/temperature gauge

16 Cold water ﬁll line — see Figure 15, page 14 for typical

components

17 Balancing valve

19 Chiller

20 Strainer

21 Check valve

22 System supply

23 System return

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Multiple boiler installations

Placing multiple boilers

1. Locate multiple boilers in boiler room according to:

a. Figure 28 (side-to-side), or b. Figure 29 (back-to-back).

2. Provide the clearances indicated in the illustrations listed above to provide for access and servicing. If these recommended dimensions are not possible, provide at least the recommended service clearances given on page 6. Also follow local codes.

3. Construct boiler foundation if boiler room ﬂoor is uneven or if there is a danger of ﬂooding. Size foundation to allow for clearance and spacing dimensions shown in the illustrations at right.

4. Chalkline boiler locations on foundation or boiler room ﬂoor.

5. Uncrate, assemble and mount boilers according to instructions in this manual.

6. Provide clearance for installation of venting, air piping, gas piping, expansion tank, primary circulator and other accessories.

Controlling multiple GWC boilers

1. Multiple GWC boilers can be controlled using any boiler control/sequencing system that provides an isolated contact for call for heat (connected to the boiler's T-T terminals).

Figure 28 Side-to-side mounting of multiple GWC boilers, showing

RECOMMENDED clearances

Figure 29 Back-to-back installation of multiple GWC boilers,

showing RECOMMENDED clearances

Piping multiple GWC boilers

1. See suggested piping diagrams in this manual. Contact Williamson-Thermoﬂo for assistance for systems not covered.

2. Always pipe the boilers on a secondary loop in a primary/secondary circuit as shown in the examples in this manual.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Multiple boiler water piping

Secondary header piping installation

1. Main header and secondary header pipe sizing.

a. New system — See page 15.

b. Replacing boilers in an existing system — Without reducing

size, connect system supply and return lines. Install tees or crosses for secondary headers as shown in Figure 30 or Figure 31. Size headers to handle total connected boiler output as shown.

2. Provide connections in main header for secondary headers as close as possible to the midpoint of multiple boilers.

a. Use tees for four or less boilers, as in Figure 30.

b. Use either tees (Figure 30) or crosses (Figure 31) for ﬁve or

more boilers.

3. Secondary header placement:

a. To alternate spacing for supply and return lines to boilers,

reverse the short-end and long-end of the headers as shown in Figure 30 and Figure 31.

b. Return header must be on the return side of the main and sup-

ply header must be on the supply side of the main. Drawings in this manual show ﬂow in system main from right to left. For system ﬂowing left to right, reverse the locations of the manifolds accordingly.

4. Connect from secondary header branches to boiler supply and return connections using copper or steel pipe, sized for the required ﬂow rate.

5. Provide a ﬂow/check valve in the supply piping of each boiler as shown in piping diagrams in this manual. Install an isolation valve on the supply and return of each boiler as shown. Some local codes may require the use of individual water level controls and limits on each boiler when isolation valves are installed.

6. Install main system air eliminator and primary circulator in supply piping as shown in piping diagrams. Place expansion tank on suction side of system circulator as shown.

7. Install system accessories as shown in drawings.

8. Piping recommendation drawings:

a. Figure 30 and Figure 31 show details of secondary headers. b. Figure 32, page 25 is a schematic piping drawing showing the

locations of typical boiler piping and system piping, including limits and other devices often required by local codes.

c. Figure 33, page 26 and Figure 34, page 27 are three-dimensional

piping drawings of typical multiple boiler installation.

d. Figure 35, page 28 shows recommended piping when an isolat-

ing heat exchanger is needed.

9. If desired, other primary/secondary piping arrangements can be used.

Maximum connected load per header:

2-inch header — 450 MBH 3-inch header — 1400 MBH 4-inch header — 2900 MBH

Figure 30

Figure 31 Double-sided secondary header, typical

Single-sided secondary header, typical

When using isolation valves on each boiler, some codes

may require providing a low water control and additional limit for each boiler. Consult local codes to determine if omission of the individual boiler isolation valves may allow the use of a single water level control and additional limit for the entire multiple boiler system.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Multiple boiler water piping (continued)

Figure 32 Piping schematic — typical for multiple GWC boilers, using secondary headers

Legend — Figure 32

1 Flow/check valve (each boiler)

2 Isolation valves (when used)

3 Cap

4 Secondary header (supply) — layout and size per

page 24

5 Secondary header (return) — layout and size per

page 24

6 Primary circulator

7 Expansion tank (diaphragm type)

8 System air eliminator

9 System automatic air vent

10 Pressure reducing valve

11 Check valve or backﬂow preventer, as required by applicable

codes

12 Isolation valve

13 Water ﬂow switch (when used)

14 Supply water temperature control (when used)

15 Low water cutoff (when used) (place above primary header)

16 Cold water ﬁll line — see Figure 15, page 14 for typical

components

18 System supply

19 System return

20 (Not shown) Boiler relief valve and discharge piping, installed

per GWC Boiler Manual

30 Long end of secondary header

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Multiple boiler water piping (continued)

Figure 33 Piping layout — typical for multiple GWC boilers, using secondary headers (2-boiler system)

1 Flow/check valve (each boiler) 2 Isolation valves (when used) 3 Caps 4 Secondary header (supply) — layout and size per page 24 5 Secondary header (return) — layout and size per page 24 6 Primary circulator 7 Expansion tank (diaphragm type) 8 System air eliminator 9 System automatic air vent 16 Cold water ﬁll line — see Figure 32, page 25 for typical com-

ponents

Legend — Figure 33

17 3-way diverting valve (operated by DHW aquastat — valve end

switch connects across boiler thermostat terminals) 18 System supply 19 System return 20 Boiler relief valve and discharge piping, installed per GWC Boiler

Manual 21 Indirect-ﬁred storage water heaters — Example is shown connect-

ed to one boiler of the system. The indirect water heater could

also be connected with a secondary connection off the main

header, as in Figure 34, page 27.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Multiple boiler water piping (continued)

Figure 34 Piping layout — typical for multiple GWC boilers, with DHW storage heaters (4-boiler system)

1 Flow/check valve (each boiler)

2 Isolation valves (when used)

3 Caps

4 Secondary header (supply) — layout and size

per page 24

5 Secondary header (return) — layout and size

per page 24

6 Primary circulator

7 Expansion tank (diaphragm type)

8 System air eliminator

9 System automatic air vent

16 Cold water ﬁll line — see Figure 32, page 25

for typical components

18 System supply

19 System return

20 Boiler relief valve and discharge piping,

installed per GWC Boiler Manual

Suggested DHW boiler-side pipe sizing

(for max 0.04 feet head loss per foot of total equivalent length, TEL)

Flow rate Size Flow rate Size

1 – 4 gpm ¾” 22 – 45 gpm 2”

4 – 8 gpm 1” 45 – 75 gpm 2½”

8 – 14 gpm 1¼” 75 - 140 gpm 3”

14 – 22 gpm 1½” 140 – 290 gpm 4”

Legend — Figure 34

21 Indirect-ﬁred storage water heaters — Example is shown with a boiler

water circulator on each water heater. Alternatively, the water heaters could be connected with reverse return piping, using a common circulator.

22 Boiler water inlet

23 Boiler water outlet

24 DHW boiler-side circulators

25 DHW boiler-side return secondary header

26 DHW boiler-side supply secondary header

27 Flow/check valves (to prevent induced or gravity ﬂow in heating system or

DHW piping)

28 Check valve to prevent heat migration in heating system

29 Drain valves

30 Sensor for BCP (boiler control panel), when used

Note: See water heater manual for DHW piping — The DHW piping must also

be manifolded together since the boiler-side piping is manifolded. If DHW heaters supply separate DHW circuits, provide an individual circulator for each water heater, and control each circulator by its water heater’s aquastat.

This piping is sug-

geste d on ly. Th e layout above should be controlled with a boiler sequencing panel that provides DHW operation as well. Wire the heating system circulator to operate only on call for heat. Alternatively, use the boiler sequencing panel to provide domestic priority by disabling the heating system circulator any time there is a DHW call for heat. The boiler internal circulators operate on any call for heat, whether heating system or DHW. Offset the DHW boiler-side supply and return manifolds as shown so the total run of pipe and ﬁttings to each of the water heaters is approximately equal.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Multiple boiler water piping (continued)

Figure 35 Piping layout — typical for multiple GWC boilers, using isolation exchanger

Use isolation heat

exchanger for:

1. Large volume systems with high mineral content in water.

2. Systems exposed to untreated quantities of makeup water.

3. Old systems severely contaminated with scale and rust buildup inside piping and heat distribution units.

4. Process applications.

5. Commercial service water applications.

6. High water pressure applications, requiring pressure relief setting in heating system more than 50 PSIG (tall buildings). See notes below.

1 Flow/check valve (each boiler) 2 Isolation valves (when used) 3 Cap 4 Secondary header (supply) — layout

and size per page 24

5 Secondary header (return) — layout

and size per page 24

6a Heating system circulator (exchang-

er tube-side) 6b Heat exchanger shell-side circulator 7 Expansion tanks (diaphragm type) 8 System air eliminator

9 System automatic air vent

13 Cold water supply connections

16 Cold water ﬁll line — see Fig-

18 Heating system supply

19 Heating system return

20 Boiler relief valve and discharge pip-

30 Sensor for BCP (boiler control

Legend — Figure 35

ure 32, page 25 for typical components

ing, installed per GWC Boiler Manual

panel), when used

Notes:

1. Contact heat exchanger manufacturer for heat exchanger shell-side and tube-side piping and circulator requirements. Tube-side ﬂow and temperatures must meet heating system requirements.

2. Contact heat exchanger manufacturer for sizing heat exchanger.

3. Heat exchanger shell-side circuit requires its own expansion tank as shown.

4. Heating system circuit requires its own expansion tank, as shown, plus its own relief valve set to protect heating system and heat exchanger piping and components.

5. When individual isolation valves are used, individual boiler and level controls may be required.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Venting & air — general

GWC boilers must be vented and

supplied with combustion and ventilation air using piping and methods described in this manual

Inspect ﬁnished vent and air piping

Failure to provide a properly-installed

Every boiler must have its own vent.

DO NOT common vent with any other

appliance.

thoroughly to ensure all are airtight and comply with the instructions provided and with all requirements of applicable codes.

vent and air system will cause severe personal injury or death.

If the vent/air piping conﬁgurations

covered in the GWC boiler manual cannot be applied for a particular installation, contact WilliamsonThermoﬂo for assistance. Other conﬁgurations may be available.

Where vent piping is routed through

an unheated space

1 inch of foil-faced ﬁberglass insulation on the length of the vent pipe in the unheated space.

, apply minimum

When removing a boiler from an existing common vent system

The GWC boiler cannot be common vented with any other appliance.

boiler CANNOT use the existing common vent. The GWC boiler requires its own vent and air piping, as speciﬁed in this manual. This may cause a problem for the appliances that remain on the old common vent, because the vent may be too large. The following test, required by ANSI Z21.13, is intended to check for proper operation of the appliances remaining on the old common vent system.

When an existing boiler is replaced with a GWC boiler, the GWC

Vent system verication

At the time of removal of an existing boiler, the following steps shall be followed with each appliance remaining connected to the common venting system placed in operation, while the other appliances remaining connected to the common venting system are not in operation. Seal any unused openings in the common venting system.

Existing vent test procedure

(The following is intended to test whether the appliances remaining on an existing vent system will operate

satisfactorily.)

Installations must comply with local

requirements and with the National Fuel Gas Code, ANSI Z223.1 for U.S. installations or CSA B149.1 or B149.2 for Canadian installations.

Use only the materials listed in this

manual for vent and air pipe and ﬁttings. See Figure 40, page 33.

If used, a masonry chimney can

ONLY be used as a PIPE CHASE for vent and air pipes

piping must be installed as instructed in this manual and all joints must be sealed. The chimney must be used only for GWC boilers. NO OTHER appliance or ﬁreplace can be connected to the chimney. The chimney must be straight, with no offsets, and the vent and air piping materials must comply with this instruction manual. The chimney must be ﬁtted with a sealed access opening, through which the interior of the chimney can be inspected. The chimney (and liner, if installed) must be inspected at least once annually to verify condition.

Failure to comply could result in severe

personal injury, death or substantial property damage.

— The vent and air

1. Visually inspect the venting system for proper size and horizontal pitch and determine there is no blockage or restriction, leakage, corrosion or other deﬁciencies which could cause an unsafe condition.

2. Test vent system — Insofar as is practical, close all building doors and windows and all doors between the space in which the appliances remaining connected to the common venting system are located and other spaces of the building. Turn on clothes dryers and any appliance not connected to the common venting system. Turn on any exhaust fans, such as range hoods and bathroom exhausts, so they will operate at maximum speed. Do not operate a summer exhaust fan. Close ﬁreplace dampers.

3. Place in operation the appliance being inspected. Follow the lighting instructions. Adjust thermostat so appliance will operate continuously.

4. Test for spillage at draft hood relief opening after 5 minutes of main burner operation. Use the ﬂame of a match or candle, or smoke from a cigarette, cigar, or pipe.

5. After it has been determined that each appliance remaining connected to the common venting system properly vents when tested as outlined herein, return doors, windows, exhaust fans, ﬁreplace dampers, and any other gas-burning appliance to their previous conditions of use.

Any improper operation of common venting system should be corrected so the installation conforms with the National Fuel Gas Code, ANSI Z223.1 — latest edition. Correct by re-sizing to approach the minimum size as determined using the appropriate tables in Part 11 of that code. Canadian installations must comply with B149.1 or B149.2 Installation Code.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Venting & air — general (continued)

Provide combustion air:

DIRECT VENT — The installation must provide com-

bustion air piping. In addition, ventilation openings may be required.

DIRECT EXHAUST — The installation must provide

combustion air openings to the boiler space.

ALL APPLICATIONS — The installation must provide

combustion air openings as needed for other appliances in the space.

Vent and air termination options

1. Vent and air piping must terminate out the sidewall or through the roof of the building, using only one of the methods described in this manual. See Figure 39, page 32 and Figure 40, page 33 for allowable conﬁgurations and piping materials.

DIRECT VENT installations

1. For direct venting, combustion air must be piped from outside to the boiler, following the instructions in this manual, and compliant with all applicable codes.

2. Ventilation openings are required for some spaces. See Figure 42, page 36.

3. If other appliances are located in the same space with the GWC boiler, provide openings shown in Figure 42, page 36.

If combustion and ventilation air openings are not provided

as directed above and the room does not have adequate ventilation, the higher temperature in the space may result in reduced component life.

Combustion air contamination:

Ensure that the combustion air will

not contain any of the contaminants in Figure 36

DO NOT place combustion air supply

openings or intake terminations near a swimming pool, for example.

Avoid areas subject to exhaust fumes

from laundry facilities. These areas will always contain contaminants.

Figure 36

Products to avoid

Spray cans containing chloro/ﬂuorocarbons

Permanent wave solutions

Chlorinated waxes/cleaners

Chlorine-based swimming pool chemicals

Calcium chloride used for thawing

Sodium chloride used for water softening

Refrigerant leaks

Paint or varnish removers

Hydrochloric acid/muriatic acid

Cements and glues

Antistatic fabric softeners used in clothes dryers

Chlorine-type bleaches, detergents, and cleaning solvents found in household laundry rooms

Corrosive contaminants and sources

DIRECT EXHAUST installations

1. Combustion and ventilation air must be provided in the boiler room on direct exhaust installations. Follow all instructions in this manual (see page 47 for air opening instructions) and all applicable codes to provide required air openings.

DO NOT sidewall vent DIRECT EXHAUST APPLICATIONS

at altitudes above 5,500 feet. Sidewall venting is only allowed for DIRECT VENT applications (ducted combustion air) at altitudes above 5,500 feet.

Adhesives used to fasten building products and other similar products

Excessive dust and dirt

Areas likely to have contaminants

Dry cleaning/laundry areas and establishments

Swimming pools

Metal fabrication plants

Beauty shops

Refrigeration repair shops

Photo processing plants

Auto body shops

Plastic manufacturing plants

Furniture reﬁnishing areas and establishments

New building construction

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Venting & air — general (continued)

Manifolded combustion air option for DIRECT VENT multiple boiler installations

1. Multiple GWC boilers can use a common combustion air manifold.

a. The combustion air inlet must be located in a

sidewall (and the

same side of the building

b. See below for minimum cross sectional area of

combined air ducts.

c. Provide minimum clearance to adjacent vents

and grade/snow line as shown in Figure 37.

d. Provide minimum free area in duct (adjusted

for louver restriction) of

2,000 Btuh

e. If combustion air damper is used, wire to boil-

ers to prevent operation except after damper has opened.

ONLY air piping can be combined. DO

NOT use combined vent piping. All vent pipes must be routed and terminated individually as described in

this manual. Flue gas leakage and boiler component damage can occur. Failure to comply could result in severe personal injury, death or substantial property damage.

vents must terminate on the

1 square inch per

total boiler input.

Figure 37

Figure 38 Maintain clearances and placement between the air

Combustion air manifold option (combined air inlet, but individual vents) — must comply with Figure 41, page 35

manifold inlet and any appliance vent as shown below

Air manifold sizing

1. See Figure 107, page 101 for minimum cross sectional area of combined air ducts.

2. CALCULATE required cross section (for area in square inches):

MIN. AREA = TOTAL MBH INPUT DIVIDED BY 2

3. Example: a. A multiple boiler system with (4)

boilers has a total input of 4 x 140 = 560 MBH (560,000 Btuh).

b. The required duct cross sectional area is: c.

MIN. AREA = 560 DIVIDED BY 2 = 280 sq. inches

The air manifold inlet of GWC boilers is part of direct vent connections. It is not classiﬁed as a forced air intake

with regard to spacing from adjacent boiler vents. To avoid recirculation, however, you must install the vent ter-

minations and air inlets with the clearances speciﬁed in Figure 38, page 31. The vent must be located following the

restrictions shown in Figure 41, page 35. The vent termination conﬁguration can be any of the sidewall methods

(NOT VERTICAL) shown in this manual for direct vent or direct exhaust sidewall termination installations.

VENTS MUST BE TERMINATED THROUGH THE SAME SIDE WALL AS THE AIR MANIFOLD INLET

GWC-140

THE

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Venting & air — general (cont.)

Figure 39 GWC venting and air piping — OPTIONS and PIPING LIMITS

Vent length affects boiler input — the boiler automatically derates to compensate for pressure loss through the vent.

See the derate values given in Figure 106, page 100. The longer the vent, the more the input is reduced.

Maximum vent and air pipe lengths

(Minimum length for all applications is 2 feet)

(All applications include allowance for the termination ﬁttings)

GWC Model

-070

DIRECT VENT

(combustion air piped to boiler from outside)

SIDEWALL

termination

3” PVC

Separate pipes

See page 37 See page 39 See page 41 See page 43 See page 49 See page 51

Max.

Length

(feet)

100 100 100 100 100 100

3” PVC

Concentric

[Note 1]

Max.

Length

(feet)

3” PVC

Separate pipes

Length

Max.

(feet)

VERTICAL

termination

3” PVC

Concentric

[Note 1]

Max.

Length

(feet)

DIRECT EXHAUST

(combustion air from inside)

SIDEWALL

termination

3” PVC

Coupling

or Elbow

Max.

Length

(feet)

VERTICAL

termination

3” PVC

Coupling

Length

Max.

(feet)

-105

-140

-175

Equivalent feet for elbows — deduct from maximum equivalent length of piping (does not apply to termination ﬁttings)

Note 1:

100 100 100 100 100 100

• 7 feet per for each 3-inch 90° long-radius or 45° elbow

• 16 feet for each 3-inch short-radius elbow

Use only PVC pipe DO NOT use CPVC or ABS with concentric termination kits.

IPEX 3” PVC concentric vent kits can be used with standard PVC pipe, ttings and cement (ANSI/ASTM D1785) except where ULC S636 compliance is required. For ULC S636 compliance, all pipe, ttings and cement must be IPEX System 636. When using IPEX kits, use only IPEX product code 196006 for 3” venting.

Contact Williamson-Thermoo for ordering information and availability of Williamson-Thermoo venting kits.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Venting & air — general (cont.)

Figure 40 Vent and air piping materials — Use only the materials listed below, ensuring that all materials meet

local codes

Item Material

Vent or air pipe

ttings

PVC & ABS pipe cement & primer

Vent pipe

AL29-4C

stainless

steel

Williamson-

Thermoo

bird screens

3” bird screen: W-T part number 383-500-105WT (two supplied with the boiler)

CPVC schedule 40 (Note 1) ANSI/ASTM F441

ABS-DWV schedule 40 (Note 1) ANSI/ASTM D2661

Heat Fab, Inc. — Saf-T-Vent

Z-Flex, Inc. — Z-Vent II

Dura-Vent — FasNSeal™

Metal-Fab, Inc. — CORR/GUARD

Standards for installations in:

United States Canada

Plastic piping materials

PVC schedule 40 ANSI/ASTM D1785

PVC-DWV (Note 1) ANSI/ASTM D2665

PVC ANSI/ASTM D2564 & F656

CPVC (Note 1) ANSI/ASTM F493

ABS (Note 1) ANSI/ASTM D2235

AL29-4C piping materials

Certiﬁed for Category IV and direct vent appliance venting

Williamson-Thermoo bird screens (included with boiler)

Plastic vent pipe must be certiﬁed to ULC S636 when required. (Note 2)

Air pipe can be any of those listed at left if acceptable for local codes.

—

Note 1: DO NOT use DWV, CPVC or ABS when using concentric vent termination. Use ONLY PVC schedule 40.

Note 2: IPEX PVC concentric terminations utilize PVC pipe/ﬁttings certiﬁed to ULC S636. Where ULC S636 compliance is required, use

only IPEX System 636 pipe, ﬁttings and cement.

AL29-4C vent piping — Install a PVC-to-stainless adapter supplied by the vent pipe manufacturer at the boiler vent connection

and at the termination (when using concentric PVC termination). DO NOT mix piping from different vent pipe manufacturers unless using adapters speciﬁcally designed for the purpose by the manufacturer.

Plastic piping — Do not attempt to connect different types of plastic piping together.

DO NOT use cellular core pipe.

ALL vent and air pipes require a BIRD SCREEN at each termination. Two bird

screens are supplied with each GWC boiler.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Commonwealth of Massachusetts installations

Commonwealth of Massachusetts — When the boiler is installed within the Commonwealth of Massachusetts,

the boiler must be installed by a licensed plumber or gas tter. Read and comply with the instructions below.

(a) For all sidewall horizontally-vented gas-fueled equipment

installed in every dwelling, building or structure used in whole or in part for residential purposes, including those owned or operated by the Commonwealth and where the side wall exhaust vent termination is less than seven (7) feet above ﬁnished grade in the area of the venting, including but not limited to decks and porches, the following requirements shall be satisﬁed:

INSTALLATION OF CARBON MONOXIDE DETEC-

. At the time of installation of the side wall horizon-

TORS

tal vented gas fueled equipment, the installing plumber or gas fitter shall observe that a hard wired carbon monoxide detector with an alarm and battery back-up is installed on the ﬂoor level where the gas equipment is to be installed. In addition, the installing plumber or gas ﬁtter shall observe that a battery operated or hard wired carbon monoxide detector with an alarm is installed on each additional level of the dwelling, building or structure served by the side wall horizontal vented gas fueled equipment. It shall be the responsibility of the property owner to secure the services of qualiﬁed licensed professionals for the installation of hard wired carbon monoxide detectors

a. In the event that the side wall horizontally vented gas

fueled equipment is installed in a crawl space or an attic, the hard wired carbon monoxide detector with alarm and battery back-up may be installed on the next adjacent ﬂoor level.

b. In the event that the requirements of this subdivision

can not be met at the time of completion of installation, the owner shall have a period of thirty (30) days to comply with the above requirements; provided, however, that during said thirty (30) day period, a battery operated carbon monoxide detector with an alarm shall be installed.

APPROVED CARBON MONOXIDE DETECTORS. Each

carbon monoxide detector as required in accordance with the above provisions shall comply with NFPA 720 and be ANSI/UL 2034 listed and IAS certiﬁed.

SIGNAGE. A metal or plastic identiﬁcation plate shall

be permanently mounted to the exterior of the building at a minimum height of eight (8) feet above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or equipment. The sign shall read, in print size no less than one-half (1/2) inch in size, “GAS VENT DIRECTLY BELOW. KEEP CLEAR OF ALL OBSTRUCTIONS.”

INSPECTION. The state or local gas inspector of the

side wall horizontally vented gas fueled equipment shall not approve the installation unless, upon inspection, the inspector observes carbon monoxide detectors and signage installed in accordance with the provisions of 248 CMR 5.08(2)(a) 1 through 4.

(b)

EXEMPTIONS: The following equipment is exempt from

248 CMR 5.08(2)(a)1 through 4:

1. The equipment listed in Chapter 10 entitled “Equipment Not Required To Be Vented” in the most current edition of NFPA 54 as adopted by the Board; and

2. Product Approved side wall horizontally vented gas fueled equipment installed in a room or structure separate from the dwelling, building or structure used in whole or in part for residential purposes.

(c)

MANUFACTURER REQUIREMENTS — GAS EQUIPMENT VENTING SYSTEM PROVIDED

Product Approved side wall horizontally vented gas equipment provides a venting system design or venting system components with the equipment, the instructions provided by the manufacturer for installation of the equipment and the venting system shall include:

1. Detailed instructions for the installation of the venting system design or the venting system components; and

2. A complete parts list for the venting system design or venting system.

(d)

MANUFACTURER REQUIREMENTS — GAS EQUIPMENT VENTING SYSTEM NOT PROVIDED

turer of a Product Approved side wall horizontally vented gas fueled equipment does not provide the parts for venting the ﬂue gases, but identiﬁes “special venting systems”, the following requirements shall be satisﬁed by the manufacturer:

1. The referenced “special venting system” instructions shall be included with the appliance or equipment installation instructions; and

2. The “special venting systems” shall be Product Approved by the Board, and the instructions for that system shall include a parts list and detailed installation instructions.

(e) A copy of all installation instructions for all Product Approved

side wall horizontally vented gas fueled equipment, all venting instructions, all parts lists for venting instructions, and/or all venting design instructions shall remain with the appliance or equipment at the completion of the installation.

. When the manufacturer of

. When the manufac-

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Vent termination requirements

Figure 41 The vent termination must be located to meet all requirements below (also applies to vertical vent terminations).

For Canadian installations, defer to the requirements of CSA B149.1 or B149.2 Installation Code.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT VENT — Boiler room air openings

Figure 42 Combustion and ventilation air openings for GWC Direct Vent installations

The GWC boiler CANNOT be in the same space with other appliances if clearances around the GWC are less than

the recommended service clearances shown in Figure 2, page 6.

Air openings

The required air opening sizes below are FREE AREA, after reduction for louver obstruction. Note the exception below for large spaces.

GWC boiler WITH other

appliances in room

TWO openings, each at least:

1 square inch per 1,000 Btuh

of all other appliances in the room

TWO openings, each at least:

1 square inch per 4,000 Btuh

of all other appliances in the room

— OR —

ONE opening **, each at least:

1 square inch per 3,000 Btuh

of all other appliances in the room

TWO openings, each at least:

1 square inch per 4,000 Btuh

of all other appliances in the room

— OR —

ONE opening **, each at least:

1 square inch per 3,000 Btuh

of all other appliances in the room

GWC boiler

WITHOUT other

appliances in room

NO openings are required if the boiler installation provides at least the recommended service clearances shown in Figure 2, page 6.

If the space is smaller than Figure 2, page 6, provide openings ONLY as shown on page 7 and Figure 4, page 7.

** NOTICE: Requirements for using the SINGLE air opening option.

SPECIAL EXCEPTION FOR LARGE SPACES (GWC WITH other appliances in room only):

TWO openings, each at least:

1 square inch per 2,000 Btuh

of all other appliances in the room

— OR —

ONE opening **, each at least:

1 square inch per 3,000 Btuh

of all other appliances in the room

A single combustion air opening can be used for cases b, c or d above (GWC with other appliances in room only), sized as listed, provided that:

• The single opening must communicate directly to the outdoors or to a space that

communicates directly with outdoors (NOT to an interior space).

• The top of the opening must be within 12 inches of the ceiling.

• The free area of the opening must be at least equal to the sum of the areas of all

equipment vent connectors in the space.

NO combustion air openings are needed when the boiler (and other appliances) are installed in a space with a volume NO LESS than 50 cubic feet per 1,000 Btuh of all appliances in the space. That is, total the input of all appliances in MBH (1,000’s of Btuh), then multiply this total times 50. The building MUST NOT be of tight construction.

Example: For a total input of 500 MBH (500,000 Btuh), the minimum volume would be 50 x 500 = 25,000 cubic feet (3,125 square feet if ceiling height is 8 feet).

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT VENT — Sidewall with separate pipes

Allowable vent/air pipe materials & lengths

Use only the vent materials and kits

listed in Figure 40, page 33. Provide pipe adapters if speciﬁed.

1. Locate the termination such that the total air piping and vent piping from the boiler to the termination will not exceed the maximum length given in Figure 39, page 32.

Determine termination location

1. The air and vent terminations must be installed as shown in Figure 43, page 37 and Figure 45, page 38.

2. The terminations must comply with clearances and limitations shown in Figure 41, page 35.

3. Locate the terminations so they are not likely to be damaged by foreign objects, such as stones or balls, or subject to buildup of leaves or sediment.

Do not exceed the maximum lengths

of the outside vent piping shown in Figure 43, page 37. Excessive length exposed to the outside could cause freezing of condensate in the vent pipe, resulting in potential boiler shutdown. In extremely cold climates, install an insulated chase around the vent piping, particularly when using longer lengths. The chase must allow for inspection of the vent pipe, and insulation must be protected from water.

Multiple vent/air terminations

1. When terminating multiple GWC boilers, terminate each vent/air connection as described in this manual.

All vent pipes and air inlets must

terminate at the same height to avoid possibility of severe personal injury, death or substantial property damage.

2. Place wall penetrations to obtain minimum clearances shown in Figure 44, page 38 for U. S. installations. For Canadian installations, provide clearances required by CSA B149.1 or B149.2 Installation Code.

3. The air inlet of a GWC boiler is part of a direct vent connection. It is not classiﬁed as a forced air intake with regard to spacing from adjacent boiler vents.

4. Combustion air (NOT vent piping) can be manifolded as shown in Figure 37, page 31.

Figure 43 INSTALLATION SEQUENCE — Separate pipes sidewall

Step 1 Read and follow all instructions in this manual. DO NOT proceed with

Step 2 Install the boiler in a location that allows proper routing of all vent and air

Step 3 Make sure the selected sidewall termination location complies with Fig-

Step 4 Use only the vent materials listed in Figure 40, page 33. Provide pipe adapt-

Step 5 Prepare the sidewall penetrations and secure the sidewall plates as instructed

Step 6 The air piping must terminate in a down-turned elbow as shown above.

Step 7 Install vent and air piping between the boiler and the sidewall openings.

Step 8 Install pipe supports every 5 feet on both the horizontal and vertical runs.

Step 9 Attach the vent termination exterior piping: Use either of the conﬁgura-

Step 10 The vent and air pipes may run up as high as 4 feet with no enclosure.

Step 11 External venting greater than 4 feet requires an insulated enclosure around

vent/air installation until you have read page 29 through page 35.

piping to the selected sidewall location.

ure 41, page 35. (Multiple boiler sidewall plates must also comply with Figure 44, page 38.)

ers where required. Vent piping and air piping lengths must not exceed the values shown in Figure 39, page 32.

this installation requires two (2) W-T sidewall termination plates and a bird screen for air and vent termination ﬁttings, unless using an AL29-4C vent termination ﬁtting with integral screen

two bird screens are supplied with the boiler for use with 3" PVC piping.

in this section. See “Prepare wall penetrations” on page 38.

The vent piping must terminate in an elbow pointed outward or away from the air inlet as shown above. See illustration above.

Slope horizontal piping downward toward the boiler at least 1/4 inch per foot. See page 46 for general guidelines.

Install a hanger support within 6 inches of any upturn in the piping.

tions shown above, as needed to ensure clearance above grade or snow line.

The vent and air pipes must be secured with braces, and all clearances and lengths must be maintained. Space braces no further than 24 inches apart.

the vent and air pipes. The vent and air terminations must exit through the enclosure as shown in the illustration above, maintaining all required clearances.

In addition to the vent materials,

. Two plates and

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT VENT — Sidewall with separate pipes (continued)

For multiple boiler applications using the manifolded

combustion air option, the vent can be terminated in an elbow as in Figure 43, page 37, or in a coupling or sidewall termination plate. The vents must be located following the restrictions in Figure 41, page 35

Figure 38, page 31.

and

In addition to the vent materials, this installation requires

two (2) W-T sidewall termination plates and a bird screen for each air and vent termination ﬁtting, unless using an AL29-4C vent termination ﬁtting with integral screen. Two plates and two bird screens are supplied with the boiler.

Prepare wall penetrations

1. Two W-T sidewall termination plates are included with each boiler. Use one of the sidewall termination plates as a template to mark air pipe and vent pipe hole locations.

a. Hole centers in the plates are 3¾" apart. b. Hole diameters are 3.14" for holes as is. Use as is for 3" AL29-4C

pipe. Remove knockout to provide 3

2. Air pipe penetration:

a. Cut a hole for the air pipe. b. Size the air pipe hole as close as desired to the air pipe outside

diameter.

3. Vent pipe penetration:

a. Cut a hole for the vent pipe. b. Cut the vent pipe hole to at least 3.9 inches for 3" PVC vent or

3.4" for 3" AL29-4C vent.

c. Insert a galvanized metal thimble in the vent pipe hole as

shown in Figure 45.

4. Follow all local codes for isolation of vent pipe when passing through ﬂoors or walls.

5. Seal exterior openings thoroughly with exterior caulk.

⁄8

" hole for 3" PVC pipe.

Figure 44

Multiple separate pipes sidewall terminations

Figure 45 Sidewall termination assembly — using

separate pipes

Termination and ttings

1. Prepare the vent termination elbow and the air termination elbow by inserting bird screens, unless using an AL29-4C vent termination ﬁtting with integral screen. (See Figure 43, page 37.) Two bird screens are supplied with the boiler.

2. When completed, the air termination elbow opening must be oriented at least 12 inches below the vent termination and at least 12 inches above grade or snow line as shown in Figure 43, page 37.

3. You can orient the vent termination elbow either directly outward or 90 degrees away from the air inlet elbow as shown in Figure 43, page 37.

4. Maintain the required dimensions of the ﬁnished termination piping as shown in Figure 43, page 37.

5. For multiple boiler terminations, see Figure 44, page 38.

6. Do not extend exposed vent pipe outside of building more than shown in this document. Condensate could freeze and block vent pipe.

If extending the vent and air pipes out from the wall,

install a coupling on each pipe. Mount the piping with the coupling ﬂush with the outer plate.

1 Vent piping 2 Air piping 3 W-T sidewall termination plates, supplied

with boiler (remove knockout if using PVC pipe; leave knockout in if using AL29-4C vent pipe)

4 Galvanized thimbles, by installer

Part number 550-142-786/0712

5 Bird screens, supplied with

boiler

6 Air inlet elbow

7 Elbow

8 Nipple

9 Elbow (vent termination)

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT VENT — Sidewall with 3” concentric

Allowable vent/air pipe materials & lengths

1. The 3” concentric termination kit must be purchased separately.

Use only the vent materials and kits listed

in Figure 40, page 33. Provide pipe adapters if speciﬁed.

2. Locate the termination such that the total air piping and vent piping from the boiler to the termination will not exceed the maximum length given in Figure 39, page 32.

3. This termination requires a 45-degree elbow that is not supplied with the termination kit. The maximum vent/air pipe lengths include allowance for this elbow.

Determine termination location

1. The concentric termination kit must be installed as shown in Figure 46, page 39.

2. The termination must comply with clearances and limitations shown in Figure 41, page 35.

3. Locate the termination so it is not likely to be damaged by foreign objects, such as stones or balls, or subject to buildup of leaves or sediment.

Multiple vent/air terminations

1. When terminating multiple GWC boilers, install each concentric termination as described in this manual.

All vent pipes and air inlets must ter-

minate at the same height to avoid possibility of severe personal injury, death or substantial property damage.

2. Place wall penetrations to obtain minimum clearance as shown in Figure 47, page 40 for U. S. installations. For Canadian installations, provide clearances required by CSA B149.1 or B149.2 Installation Code.

3. The air inlet of a GWC boiler is part of a direct vent connection. It is not classiﬁed as a forced air intake with regard to spacing from adjacent boiler vents.

Figure 46 INSTALLATION SEQUENCE — Concentric horizontal

Step 1 Read and follow all instructions in this manual. DO NOT

Step 2

Step 3 Make sure the selected sidewall termination location com-

Step 4 Use only the vent materials listed in Figure 40, page 33.

Step 5 Vent piping and air piping lengths must not exceed the

Step 6 The concentric termination must be assembled and installed

proceed with vent/air installation until you have read page 29 through page 35.

Install the boiler in a location that allows proper routing of all vent and air piping to the selected sidewall location.

plies with Figure 41, page 35. (Multiple boiler concentric terminations must also comply with Figure 47, page 40.)

Provide pipe adapters where required.

values shown in Figure 39, page 32.

before piping from the boiler to the termination.

Part number 550-142-786/0712

Step 7 Prepare the sidewall penetration — assemble the concentric

termination kit and secure the cover plates as instructed in this section. Provide the supports indicated and mount the termination assembly. See “Install termination — concentric pipes” on page 40.

Step 8 Install vent and air piping between the boiler and the

concentric vent/air termination. Slope horizontal piping downward toward the boiler at least 1/4 inch per foot. See page 46 for general guidelines.

Step 9 Install pipe supports every 5 feet on both the horizontal and

vertical runs.

Step 10 Install a hanger support within 6 inches of any upturn in

the piping.

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT VENT — Sidewall with 3” concentric (continued)

Install termination — concentric pipes

1. Assemble the vent termination as described for concentric terminations, on page 45.

If necessary, you can shorten the lengths of the inner and

outer pipes for a shorter ﬁnished assembly. But you must ensure the pipes butt correctly at both ends. Failure to properly assemble the concentric termination can result in ﬂue gas recirculation, causing possible severe personal injury or death.

2. Wall penetration: a. Preferably, use a thimble with a 4½-inch hole. If not using a

thimble, carefully use a hole saw to cut a hole not larger than 4¾ inches in diameter through the wall. The ﬁnished hole must provide a solid stop for the rain cap ribs, as shown in the inset to Figure 48.

3. Secure the termination in place so the rain cap will butt against the outside wall or outer thimble plate as shown in Figure 48, page 40.

4. Before beginning vent and air piping from the boiler to the concentric termination, mount and secure the concentric termination as shown in Figure 48, page 40.

The vent and air piping must be securely supported, and

must not rest its weight on the boiler ﬁttings. Failure to properly support the vent and air piping could result in vent piping damage, resulting in possible severe personal injury, death or substantial property damage.

Figure 47 Termination location — concentric

termination — multiple boilers — clearance from vent of one to air intake of the next

Figure 48 Installing and supporting the concentric

sidewall vent assembly

The supports/bracing used must support the termination

assembly to prevent slippage or movement.

The clamps used on the outside of the termination pipe

must not cut into the pipe or contain sharp edges that could cause a crack to form.

When inserting the partially-assembled termination

kit through the wall penetration, wrap plastic or other protection over the end of the exposed assembly to prevent debris from entering the pipes. If the air passages become blocked, the boiler will not operate. Once the rain cap has been cemented to the assembly, there is no way to correct the problem. The assembly would have to be replaced if it were cut to be removed and cleaned. Altering the assembly in any way could result in severe personal injury or death due to toxic ﬂue product emissions.

When using AL294C stainless vent pipe, use the vent

pipe manufacturer’s PVC adapter when connecting to the concentric vent attachment.

5. After the assembly has been positioned in the opening and all supports have been attached, install a bird screen (supplied with boiler) and rain cap as follows:

a. Place the bird screen on the end of the inner pipe as in Fig-

ure 54, page 45.

b. Cement the rain cap in place as shown.

Ensure that the wall material is strong

enough to prevent the rain cap from being

pushed inward if struck or pushed from the

outside.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT VENT — Vertical with separate pipes

Allowable vent/air pipe materials & lengths

Use only the vent materials and kits listed

in Figure 40, page 33. Provide pipe adapters if speciﬁed.

1. Locate the terminations such that the total air piping and vent piping from the boiler to the termination will not exceed the maximum length given in Figure 39, page 32.

Determine termination location

1. The air and vent terminations must be installed as shown in Figure 49, page 41.

2. The terminations must comply with clearances and limitations shown in Figure 41, page 35.

3. Locate the terminations so they are not likely to be damaged by foreign objects, such as stones or balls, or subject to buildup of leaves or sediment.

Multiple vent/air terminations (Figure 50)

1. When terminating multiple GWC boilers, terminate each vent/air connection as described in this section.

Terminate all vent pipes at the same

height and all air pipes at the same height to avoid possibility of severe personal injury, death or substantial property damage.

2. Place roof penetrations to obtain minimum clearance of 12 inches between edge of air intake elbow and adjacent vent pipe of another boiler for U. S. installations (see Figure 50, page 42). For Canadian installations, provide clearances required by CSA B149.1 or B149.2 Installation Code.

3. The air inlet of a GWC boiler is part of a direct vent connection. It is not classiﬁed as a forced air intake with regard to spacing from adjacent boiler vents.

Prepare roof penetrations

1. Air pipe penetration:

a. Cut a hole for the air pipe. Size the air pipe

hole as close as desired to the air pipe outside diameter.

2. Vent pipe penetration:

a. Cut a hole for the vent pipe. For either combus-

tible or noncombustible construction, size the vent pipe hole at least 0.4” larger than the vent pipe diameter (4” hole for 3” PVC).

b. Insert a galvanized metal thimble in the vent

pipe hole.

Figure 49 Separate pipes vertical termination

Step 1 Read and follow all instructions in this manual. DO NOT proceed

with vent/air installation until you have read page 29 through page 35.

Step 2 Install the boiler in a location that allows proper routing of all vent

and air piping to the selected sidewall location.

Step 3 Make sure the selected vertical termination location complies with

Figure 41, page 35. (Multiple boiler terminations must also comply with Figure 50, page 42.)

Step 4 Use only the vent materials listed in Figure 40, page 33. Provide pipe

adapters where required. Vent piping and air piping lengths must not exceed the values shown in Figure 39, page 32.

Step 5 Prepare the vertical penetrations and secure penetration components

as instructed in this section. See “Prepare roof penetrations” on page 41 and “Termination and ﬁttings” on page 42.

Step 6 The air piping must terminate in a 180-degree return bend or down-

turned elbow as shown above. The vent piping must terminate in a coupling pointed upward as shown above. Vent and air termina-

tions must be ﬁtted with bird screens as shown. Two bird screens are supplied with the boiler.

Step 7 Install vent and air piping between the boiler and the vertical termina-

tions. Slope horizontal piping downward toward the boiler at least 1/4 inch per foot. Install pipe supports every 5 feet on both the horizontal and vertical runs. Install a hanger support within 6 inches of any upturn in the piping. See page 46 for general guidelines.

Step 8 Insert the vent and air piping through the vertical penetrations and

secure the termination ﬁttings.

Step 9 Maintain clearances shown above. Vent and air terminations must

be ﬁtted with a bird screen as shown. See Figure 93, page 88 for part numbers.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT VENT — Vertical with separate pipes (continued)

3. Space the air and vent holes to provide the minimum spacings shown in Figure 49, page 41.

4. Follow all local codes for isolation of vent pipe when passing through ﬂoors, ceilings and roofs.

5. Provide ﬂashing and sealing boots sized for the vent pipe and air pipe.

Termination and ttings

1. Prepare the vent termination elbow and the air termination elbow (Figure 49, page 41) by inserting bird screens. Two bird screens are supplied with the boiler.

2. The air piping must terminate in a down-turned 180-degree return bend as shown in Figure 49, page 41. Locate the air inlet pipe no further than 12 inches from the center of the vent pipe. This placement avoids recirculation of ﬂue products into the combustion air stream.

3. The vent piping must terminate in an up-turned coupling as shown in Figure 49, page 41. The top of the coupling must be at least 1 foot above the air intake. The air inlet pipe and vent pipe can be located in any desired position on the roof, but must always be no further than 12 inches apart and with the vent termination at least 1 foot above the air intake.

Figure 50 Terminations for multiple boilers

4. Maintain the required dimensions of the ﬁnished termination piping as shown in Figure 49, page 41.

5. Do not extend exposed vent pipe outside of building more than shown in this document. Condensate could freeze and block vent pipe.

Also maintain maximum center-to-center

distances between the vent and air pipes for each boiler as shown in Figure 49, page 41.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT VENT — Vertical with 3” concentric

Allowable vent/air pipe materials & lengths

1. The 3.00” concentric termination kit must be purchased separately.

Use only the vent materials and kits

listed in Figure 40, page 33. Provide pipe adapters if speciﬁed.

2. Locate the termination such that the total air piping and vent piping from the boiler to the termination will not exceed the maximum length given in Figure 39, page 32.

3. This termination requires a 45-degree elbow that is not supplied with the termination kit. The maximum vent/air pipe lengths include allowance for this elbow.

Determine termination location

Locate the concentric vent/air termination using the following guidelines:

1. The concentric vent/air assembly must terminate as shown in Figure 52, page 44.

2. The termination must comply with the clearances and limitations shown in Figure 41, page 35.

3. Locate the termination so it is not likely to be damaged by foreign objects, such as stones or balls, or subject to buildup of leaves or sediment.

4. For Canadian installations, follow requirements of CSA B149.1 or B149.2 Installation Code.

Multiple vent/air terminations

1. When terminating multiple GWC boilers, install the concentric vent/air termination assemblies as described in this manual.

All vent outlets must terminate at the

same height to avoid possibility of severe personal injury, death or substantial property damage.

2. Place roof penetrations to obtain minimum of 12 inches between centers of adjacent vent pipe of another boiler for U. S. installations (see Figure 52, page 44).

3. The air inlet of a GWC boiler is part of a direct vent connection. It is not classiﬁed as a forced air intake with regard to spacing from adjacent boiler vents.

Prepare roof penetrations

1. Roof penetration hole: a. Cut a 5-inch diameter hole to clear the 4½-inch

termination outside diameter.

b. Insert a galvanized metal thimble in the vent

pipe hole.

2. Follow all local codes for isolation of vent pipe when passing through ﬂoors, ceilings and roofs.

3. Provide ﬂashing and sealing boots sized for the concentric termination outside diameter.

Figure 51 INSTALLATION SEQUENCE — Concentric vertical

Step 1 Read and follow all instructions in this manual. DO NOT

Step 2

Step 3 Make sure the selected vertical termination location com-

Step 4 Use only the vent materials listed in Figure 40, page 33.

Step 5 Vent piping and air piping lengths must not exceed the

Step 6 The concentric termination must be assembled and installed

Step 7 Prepare the vertical penetration(s) — assemble the concen-

Step 8 Install vent and air piping between the boiler and the

Step 9 Install pipe supports every 5 feet on both the horizontal and

Step 10 Install a hanger support within 6 inches of any upturn in

proceed with vent/air installation until you have read page 29 through page 35.

Install the boiler in a location that allows proper routing of all vent and air piping to the selected sidewall location.

plies with Figure 41, page 35. (Multiple boiler concentric terminations must also comply with Figure 52, page 44.)

Provide pipe adapters where required.

values shown in Figure 39, page 32.

before piping from the boiler to the termination.

tric termination kit and secure the penetration components as instructed in this section. Provide the supports indicated and mount the termination assembly. See “Prepare roof penetrations” on page 43 and “Mount concentric termination” on page 44.

concentric vent/air termination. Slope horizontal piping downward toward the boiler at least 1/4 inch per foot. See page 46 for general guidelines.

vertical runs.

the piping.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT VENT — Vertical with 3” concentric (continued)

Mount concentric termination

1. Mount the termination as shown in Figure 53, page 44.

2. Support the concentric vent/air termination at the roof penetration as shown in Figure 53.

• The supports/bracing used must support the termination as-

sembly to prevent vertical slippage or sideways movement.

• The clamps used on the outside of the termination pipe must

not cut into the pipe or contain sharp edges that could cause a crack to form.

The vent and air piping must be securely supported,

and must not rest its weight on the boiler ﬁttings. DO NOT drill or screw into either the vent pipe or air pipe. Failure to properly support the vent and air piping could result in vent piping damage, resulting in possible severe personal injury, death or substantial property damage.

When inserting the partially-assembled termination

kit through the roof penetration, wrap plastic or other protection over the end of the exposed assembly to prevent debris from entering the pipes. If the air passages become blocked, the boiler will not operate. Once the rain cap has been cemented to the assembly, there is no way to correct the problem. The assembly would have to be replaced if it were cut to be removed and cleaned. Altering the assembly in any way could result in severe personal injury or death due to toxic ﬂue product emissions.

Figure 52 Vertical termination — 3” PVC concentric

— single or multiple boilers

Figure 53 3” PVC concentric termination supports

When using AL294C stainless vent pipe, use the vent

pipe manufacturer’s PVC adapter when connecting to the concentric vent attachment.

Do not connect any other appliance to the vent pipe or

multiple boilers to a common vent pipe.

3. After the assembly has been positioned in the roof opening and all supports have been attached, install a bird screen (two bird screens are supplied with the boiler) and rain cap as follows:

a. Place the bird screen on the end of the inner pipe as in Fig-

ure 54, page 45.

b. Cement the rain cap in place.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Concentric termination assembly (sidewall or vertical)

Figure 54 3” PVC concentric termination assembly — DO NOT

attach the rain cap until the termination has been inserted through the roof or wall and all supports have been installed.

Assembling concentric termination

1. See Figure 54, page 45 for the details of the termination assembly.

2. Prepare the bird screen (two bird screens are supplied with the boiler). Cut the bird screen to size if required. If the bird screen must be trimmed, cut the bird screen to ﬁt the outside diameter of the PVC inner pipe supplied with the termination kit.

3. Partially assemble the vent termination kit in the sequence shown in Figure 54, page 45.

DO NOT install the rain cap and bird

screen until the assembly has been inserted through the roof (or sidewall) and all supports have been installed. Follow instructions to cover the end of the assembly with plastic before inserting through the roof penetration to prevent debris from blocking the air passages.

4. Use the following procedures to prepare termination components and cement together.

5. Deburr inside and outside of pipe ends.

6. Chamfer outside of each pipe end to ensure even cement distribution when joining.

7. Clean all pipe ends and ﬁttings.

8. Dry thoroughly.

9. Dry assemble entire vent or air piping to ensure proper ﬁt before assembling any joint.

10. For each joint:

a. Handle ﬁttings and pipes carefully to prevent

contamination of surfaces.

b. Apply primer liberally to both joint surfaces —

pipe end and ﬁtting socket.

c. While primer is still damp, lightly apply ap-

proved cement to both surfaces in a uniform coating.

d. Apply a second coat to both surfaces. Avoid

using too much cement on sockets to prevent cement buildup inside.

e. With cement still wet, insert pipe into fit-

ting, twisting ¼ turn. Make sure pipe is fully inserted.

If necessary, you can shorten the lengths

of the inner and outer pipes for a shorter ﬁnished assembly. But you must ensure the pipes butt correctly at both ends. Failure to properly assemble the concentric termination can result in ﬂue gas recirculation, causing possible severe personal injury or death.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Vent and air piping and boiler connections

DIRECT EXHAUST & DIRECT VENT

Follow termination instructions

1. Read and follow all instructions for the termination type used before proceeding with this page.

Installing vent and air piping

1. Work from the boiler to vent or air termination. Do not exceed the lengths given in the previous pages for either the air or vent piping.

a. Provide stainless pipe to PVC adapters obtained

from the stainless pipe manufacturer for connections at the boiler and at terminations, when required.

2. See Figure 55 for attaching vent (and air) pipes at the boiler.

3. Cut pipe to required lengths.

4. Deburr inside and outside of pipe ends.

5. Chamfer outside of each pipe end to ensure even cement distribution when joining.

6. Clean all pipe ends and ﬁttings. Dry thoroughly.

7. Dry assemble entire vent or air piping to ensure proper ﬁt before assembling any joint.

8. For each joint: a. Handle ﬁttings and pipes carefully to prevent

contamination of surfaces.

b. Apply primer liberally to both joint surfaces —

pipe end and ﬁtting socket.

c. While primer is still damp, lightly apply ap-

proved cement to both surfaces in a uniform coating.

d. Apply a second coat to both surfaces. Avoid

using too much cement on sockets to prevent cement buildup inside.

e. With cement still wet, insert pipe into fit-

ting, twisting ¼ turn. Make sure pipe is fully inserted.

f. Wipe excess cement from joint. Check joint to

be sure a smooth bead of cement shows around the entire joint.

9. Maintain minimum clearance of C\zn inch between vent pipe and any combustible wall or material.

10. Seal wall or ﬂoor penetration openings following local code requirements.

DIRECT EXHAUST ONLY

DIRECT EXHAUST installations — air

inlet opening protection

the bird screens supplied with the boiler into the air inlet ﬁtting to prevent foreign objects from entering the opening.

: Insert one of

Figure 55 Boiler vent and air connections

AL294C vent pipe — If using AL294C stainless vent pipe,

you must install an AL29-4C stainless vent starter at the boiler vent connection (and at the termination if using the PVC concentric termination). Use only the starter made by the vent pipe manufacturer. See Replacement parts section for available AL29-4C stainless vent starters.

1. PVC/ABS pipe — Clean and deburr inside and outside of other both ends of air and vent pipes. Chamfer boiler end of vent pipe for ease of insertion.

The vent pipe end must be smooth and chamfered to

prevent possible damage to sealing gasket in vent pipe adapter.

2. Inspect vent adapter and air inlet ﬁtting (above) — verify no obstructions or foreign objects inside.

3. Vent pipe

• Loosen vent adapter clamp screw.

• Measure 3½ inches from boiler end of vent pipe and make a

mark with felt-tip pen.

• Apply small amount of silicon grease to boiler end of vent pipe

to ease insertion.

• Insert vent pipe into adapter to depth of felt tip pen mark.

• Secure vent pipe by tightening the adapter clamp securely. Do

not overtighten. The seal is accomplished with the internal gasket. The clamp is only to hold the pipe in place.

Do not apply excessive force or bend the vent adapter

or vent pipe when inserting. The adapter or seal could be damaged.

4. Air pipe

• Clean the outer surface of the boiler end of the air pipe.

• Apply silicon sealant (Dow Corning 732

the outside end of the air pipe and to the inside of the air inlet ﬁtting.

• Insert the air pipe into the air inlet ﬁtting and give a 1/4 turn

to ensure coverage. Support until the sealant has dried.

or equivalent) to

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT EXHAUST — Boiler room air openings

Combustion air provision

The GWC boiler can use inside air if no contaminants are present in the boiler space. (If contaminants are likely to be present, install the boiler as a direct vent appliance, using the appropriate vent instructions in this manual.)

The boiler room must be ﬁtted with combustion air openings large enough to provide air for all appliances in the room. Use the following information to size the openings. Ensure the installation complies with all applicable codes and standards.

Where the GWC boiler shares a space with other appliances, the combustion air openings must be sized to handle the combined requirements of all appliances in the space.

Sizing combustion air openings

Air openings provide for ventilation (as well as combustion air) to prevent overheating of the boiler controls and boiler space. Air is also needed for other appliances located in the same space.

Use Figure 56, page 48, selecting the appropriate installation conditions.

Air openings must be sized to handle all appliances and air

movers (exhaust fans, etc.) using the air supply.

The sizing given in Figure 56, page 48 is based on the National Fuel Gas Code, ANSI Z223.1, allowing adequate air openings for gravity-vented gas appliances (Category I) in addition to that needed for the GWC boiler.

The air openings recommended in Figure 56, page 48 will allow adequate ventilation and combustion air provided the boiler room is not subjected to negative pressure due to exhaust fans or other mechanical ventilation devices.

Refer to the National Fuel Gas Code for dealing with other conditions.

Free area — louver allowance

The free area of openings means the area after reduction for any installed

louvers or grilles

openings.

. Be sure to consider this reduction when sizing the air

Special considerations

Tight construction

ANSI Z223.1 defines unusually tight construction where:

1. Walls and ceilings exposed to the outside atmosphere have a continuous water vapor retarder with a rating of 1 perm or less with openings gasketed, and . . .

2. Weather-stripping has been added on openable windows and doors, and . . .

3. Caulking or sealants are applied to areas such as joints around windows and door frames, between sole plates and ﬂoors, between wall-ceiling joints, between wall panels, at penetrations for plumbing, electrical, and gas lines, and in other openings.

For buildings with such construction, provide air openings into the building from outside, sized per the appropriate case in Figure 56, page 48 if appliances are to use inside air for combustion and ventilation.

Exhaust fans and air movers

The appliance space must never be under a negative pressure unless all appliances are installed as direct vent. Always provide air openings sized not only to the dimensions required for the ﬁring rate of all appliances, but also to handle the air movement rate of the exhaust fans or air movers using air from the building or space.

Motorized air dampers

If the air openings are ﬁtted with motorized dampers, electrically interlock the damper to:

• Prevent the boiler from ﬁring if the damper is not fully open.

• Shut the boiler down should the damper close during boiler operation.

To accomplish this interlock, wire an (proving the damper open) in series with the thermostat input to the boiler. The boiler will not start if this contact is open, and will shut down should it open during operation.

isolated contact

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT EXHAUST —

Boiler room air openings

(cont.)

Figure 56 MINIMUM combustion air openings for direct exhaust applications — ALL OPENING SIZES ARE FREE AREA

The GWC boiler CANNOT be in the same space with other appliances if

clearances around the GWC are less than the recommended service clearances shown in Figure 2, page 6.

Air openings

The required air opening sizes below are FREE AREA, after reduction for louver obstruction. Note the exception below for large spaces.

GWC boiler WITH other

appliances in room

TWO openings, each at least:

1 square inch per 1,000 Btuh

of all appliances in the room

TWO openings, each at least:

1 square inch per 4,000 Btuh

of all appliances in the room

— OR —

ONE opening **, each at least:

1 square inch per 3,000 Btuh

of all appliances in the room

If the space is smaller than Figure 2, page 6, provide openings ONLY as shown on page 7 and Figure 4, page 7.

GWC boiler

WITHOUT other

appliances in room

TWO openings, each at least:

1 square inch per 4,000 Btuh

of all appliances in the room

TWO openings, each at least:

1 square inch per 4,000 Btuh

of all appliances in the room

— OR —

ONE opening **, each at least:

1 square inch per 3,000 Btuh

of all appliances in the room

** NOTICE: Requirements for using the SINGLE air opening option.

SPECIAL EXCEPTION FOR LARGE SPACES:

TWO openings, each at least:

1 square inch per 4,000 Btuh

of all appliances in the room

— OR —

ONE opening **, each at least:

1 square inch per 3,000 Btuh

of all appliances in the room

TWO openings, each at least:

1 square inch per 2,000 Btuh

of all appliances in the room

— OR —

ONE opening **, each at least:

1 square inch per 3,000 Btuh

of all appliances in the room

A single combustion air opening can be used for cases b, c or d above, sized as listed, provided that:

• The single opening must communicate directly to the outdoors or to a space that

communicates directly with outdoors (NOT to an interior space).

• The top of the opening must be within 12 inches of the ceiling.

• The free area of the opening must be at least equal to the sum of the areas of all

equipment vent connectors in the space.

Example: For a total input of 500 MBH (500,000 Btuh), the minimum volume would be 50 x 500 = 25,000 cubic feet (3,125 square feet if ceiling height is 8 feet).

TWO openings, each at least:

1 square inch per 4,000 Btuh

of all appliances in the room

— OR —

ONE opening **, each at least:

1 square inch per 3,000 Btuh

of all appliances in the room

TWO openings, each at least:

1 square inch per 2,000 Btuh

of all appliances in the room

— OR —

ONE opening **, each at least:

1 square inch per 3,000 Btuh

of all appliances in the room

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT EXHAUST — Sidewall

DO NOT sidewall vent DIRECT EX-

HAUST APPLICATIONS

at altitudes above 5,500 feet. Sidewall venting is only allowed for DIRECT VENT ap- plications (ducted combustion air) at altitudes above 5,500 feet.

Allowable vent/air pipe materials & lengths

Use only the vent materials and kits

listed in Figure 40, page 33. Provide pipe adapters if speciﬁed.

1. Locate the termination such that the total air piping and vent piping from the boiler to the termination will not exceed the maximum length given in Figure 39, page 32.

Determine termination location

1. The air and vent terminations must be installed as shown in Figure 57 and in Figure 58, page 50.

2. The terminations must comply with clearances and limitations shown in Figure 41, page 35.

3. Locate the termination so it is not likely to be damaged by foreign objects, such as stones or balls, or subject to buildup of leaves or sediment.

Multiple vent/air terminations

1. Terminate each vent of multiple direct exhaust GWC boilers as described in this manual for individual vents.

2. Space terminations as required for best installation practices and required maintenance.

a. External venting greater than 4 feet

requires an enclosure around the vent pipe. The vent termination must exit through the enclosure as shown in Figure 57, page 49, maintaining all required clearances.

Prepare wall penetration

In addition to the vent materials,

this installation requires two (2) sidewall termination plates and one (1) bird screen, unless using an AL29-4C termination ﬁtting with integral screen. Sidewall plates can be made by cutting W-T sidewall plates in half or can be fabricated and supplied by the installer. Two two-hole plates and two bird screens are supplied with the boiler for use with 3" PVC pipe.

Figure 57 INSTALLATION SEQUENCE — Direct exhaust sidewall

Step 1 Read and follow all instructions in this manual. DO NOT proceed with

Step 2 Install the boiler in a location that allows proper routing of vent piping to

Step 3 Make sure the selected sidewall termination location complies with Fig-

Step 4 Use only the vent materials listed in Figure 40, page 33. Provide pipe adapt-

Step 5 Prepare the sidewall penetration and secure the sidewall plate as instructed

Step 6 The vent piping can terminate using a coupling or down-turned elbow, or

Step 7 Install vent piping between the boiler and the sidewall opening. Slope

Step 8 Install pipe supports every 5 feet on both the horizontal and vertical runs.

Step 9 Attach the vent termination exterior piping, if used: Use any of the con-

Step 10 The vent pipe may run up as high as 4 feet with no enclosure. The vent

Step 11 External venting greater than 4 feet requires an insulated enclosure around

vent installation until you have read page 29 through page 35, page 47 and page 48.

the selected sidewall location.

ure 41, page 35.

ers where required. Vent piping length must not exceed the value shown in Figure 39, page 32.

requires two (2) sidewall termination plates and one bird screen, unless using an AL29-4C termination ﬁtting with integral screen

Sidewall plates can be made by cutting a W-T sidewall plate in half or can be fabricated and supplied by the installer. Two two-hole plates and two bird screens are supplied with the boiler.

in this section. See “Prepare wall penetration” on page 49 and “Termination and ﬁttings” on page 50.

snorkeled and terminated with an elbow. See illustration above. The coupling or elbow must butt against the outside plate.

horizontal piping downward toward the boiler at least 1/4 inch per foot. See page 46 for general guidelines.

Install a hanger support within 6 inches of any upturn in the piping.

ﬁgurations shown above, as needed to ensure clearance above grade or snow line.

pipe must be secured with braces, and all clearances and lengths must be maintained. Space braces no further than 24 inches apart.

the vent and air pipes. The vent and air terminations must exit through the enclosure as shown in the illustration above, maintaining all required clearances.

In addition to the vent materials, this installation

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT EXHAUST — Sidewall (continued)

Where the vent penetrates an outside wall, the annular

space around the penetration must be permanently sealed using approved materials to prevent entry of combustion products into the building.

1. Wall penetration: a. Cut a rough opening large enough to clear the diameter

of the metal thimble used.

b. The metal plates can be ﬁeld fabricated or can be made by

cutting a W-T sidewall termination plate in half — two 2-hole plates are supplied with the boiler.

c. The W-T plate hole diameters are 3.14" for holes as is. Use

as is for 3" AL29-4C pipe. Remove knockout to provide

⁄8" hole for 3" PVC pipe.

d. If ﬁeld fabricating the plates, the hole diameters in the

metal plates must be 3

⁄8” for PVC pipe. For AL29-4C vent pipe and coupling (or elbow) — size hole large enough to clear vent pipe, but small enough to prevent the termination coupling (or elbow) from being pushed through.

e. Insert a galvanized metal thimble (by installer) in the vent

pipe hole as shown in Figure 58.

2. Follow all local codes for isolation of vent pipe when passing through ﬂoors or walls.

Termination and ttings

1. If using a coupling or elbow for the termination, prepare the vent termination ﬁtting (Figure 58, page 50) by inserting a bird screen, unless using an AL29-4C termination ﬁtting with integral screen. Bird screens are not supplied with the GWC boiler. Purchase separately from Williamson-Thermoﬂo. See Figure 93, page 88 for part numbers.

2. You can install the vent termination using either of the conﬁgurations shown in Figure 57, page 49.

3. Maintain the required dimensions of the ﬁnished termination piping as shown in Figure 57, page 49.

4. Do not extend exposed vent pipe outside of the building more than shown in this document. Condensate could freeze and block vent pipe.

Figure 58 DIRECT EXHAUST — Sidewall — termination

assembly and termination options — all parts by installer except where shown otherwise

LEGEND for Figure 58

1 Vent piping

2 Sidewall termination plates — two 2-hole plates are supplied with the

boiler — one of these can be cut in half for use in direct exhaust venting or the plate can be ﬁeld fabricated) — plate holes can be used as is for 3" AL29-4C vent pipe. Remove knockout to provide clearance hole for 3" PVC pipe.

3 Galvanized thimble

4 Vent termination elbow

5 Bird screen — two bird screens are supplied with each boiler

6 Extend vent pipe through outside plate enough to attach termination

coupling (or elbow when snorkeled).

7 Snorkel option (to elevate vent termination) — requires bird screen (see

Figure 93, page 88 for part numbers)

8 Coupling option — requires bird screen — two bird screens are supplied

with each boiler

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

DIRECT EXHAUST — Vertical

Allowable vent/air pipe materials & lengths

Use only the vent materials and kits listed

in Figure 40, page 33. Provide pipe adapters if speciﬁed.

1. Locate the termination such that the total air piping and vent piping from the boiler to the termination will not exceed the maximum length given in Figure 39, page 32.

Determine termination location

1. The vent terminations must be installed as shown in Figure 59, page 51.

2. The terminations must comply with clearances and limitations shown in Figure 41, page 35.

3. Locate the termination so it is not likely to be damaged by foreign objects, such as stones or balls, or subject to buildup of leaves or sediment.

Multiple vent/air terminations

1. Terminate each vent of multiple direct exhaust GWC boilers as described in this manual for individual vents.

2. Space terminations as required for best installation practices and required maintenance.

Prepare roof penetration

1. Vent pipe penetration: a. Cut a hole for the vent pipe. For either com-

bustible or noncombustible construction, size the vent pipe hole at least 0.5” larger than the vent pipe diameter.

b. Hole diameter in the metal plates must be at

least 4” for PVC pipe. For AL29-4C vent pipe and coupling (or elbow) — size hole 0.5” larger than vent pipe outside diameter.

c. Insert a galvanized metal thimble in the vent

pipe hole.

2. Follow all local codes for isolation of vent pipe when passing through ﬂoors, ceilings and roofs.

3. Provide ﬂashing and sealing boots sized for the vent pipe and air pipe.

Where the vent penetrates the roof, the an-

nular space around the penetration must be permanently sealed using approved materials to prevent entry of combustion products into the building.

Figure 59 INSTALLATION SEQUENCE — Direct exhaust vertical

Step 1 Read and follow all instructions in this manual. DO NOT

Step 2

Step 3 Make sure the selected vertical termination location com-

Step 4 Use only the vent materials listed in Figure 40, page 33.

Step 5 Prepare the vertical penetration and secure penetration

Step 6 The vent piping must terminate in a coupling pointed

Step 7 Install vent and air piping between the boiler and the verti-

Step 8 Maintain minimum clearance of C\zn inch between vent pipe

Step 9 Insert the vent piping through the vertical penetration and

Step 10 Maintain clearances shown above. Vent terminations must

proceed with vent/air installation until you have read page 29 through page 35, page 47 and page 48.

Install the boiler in a location that allows proper routing of all vent and air piping to the selected sidewall location.

plies with Figure 41, page 35.

Provide pipe adapters where required. Vent piping and air piping lengths must not exceed the values shown in Figure 39, page 32.

components as instructed in this section. See “Prepare roof penetrations” on page 41 and “Termination and ﬁttings” on page 42.

upward

as shown. Two bird screens are supplied with the boiler.

cal termination. Slope horizontal piping downward toward the boiler at least 1/4 inch per foot. Install pipe supports every 5 feet on both the horizontal and vertical runs. Install a hanger support within 6 inches of any upturn in the piping. See page 46 for general guidelines.

and any combustible wall or material.

secure the termination coupling.

be ﬁtted with a bird screen as shown. See Figure 93, page 88 for part numbers.

as shown above. Fit the coupling with a bird screen

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Gas piping

Connecting gas supply piping

Do not connect gas supply to boiler or at-

tempt to operate boiler unless the correct oriﬁce plate has been veriﬁed or installed in accordance with page 8.

Except where otherwise instructed in

this manual, do not attempt to measure or adjust the outlet pressure setting of the gas valve.

set to a slight negative pressure, and is operated as a negative-pressure regulated valve.

Failure to comply will result in malfunc-

tion of the boiler, causing severe personal injury, death or substantial property damage.

1. Refer to Figure 60 to connect gas supply to ½” NPT boiler gas connection. Use wrench to hold factoryinstalled gas cock.

2. Support piping with hangers, not by boiler or its accessories.

3. Purge all air from gas supply piping.

4. Before placing boiler in operation, check boiler and test all gas connections for leaks.

Do not check for gas leaks with an

open ame

to use bubble test or check for gas leaks can cause severe personal injury, death or substantial property damage.

The gas valve is factory

— use bubble test. Failure

Figure 60 Gas supply connection to GWC boiler gas manifold

Close manual main shutoff valve dur-

ing any pressure testing at less than 14” w.c.

Disconnect boiler and gas valve from

gas supply piping during any pressure testing greater than 14” w.c.

5. Use pipe dope compatible with propane gases. Apply sparingly only to male threads of pipe joints so that pipe dope does not block gas ﬂow.

Failure to apply pipe dope as detailed

above can result in severe personal injury, death or substantial property damage.

Honeywell VK8115V gas valve

• The Honeywell VK8115V gas valve operates with DC voltage.

• The black power plug that connects to the gas valve contains

a DC rectiﬁer.

• When the gas valve is energized, approximately 19 to 21 volts DC voltage should be measured across the two outer pins of the gas valve connector plug.

• There are 4 pins on the gas valve and 3 pin receptacles in the plug. Only the two outer pins are used for powering the valve.

• To measure voltage, remove the screw and slightly lift the plug until meter leads can touch end pins.

• Run boiler and test for proper voltage.

• Remember to re-install plug and tighten screw after testing.

Continuity cannot be checked in the gas valve con-

nector plug wiring due to the rectiﬁer.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Gas piping (continued)

Natural Gas

1. Refer to Figure 61 for pipe length and diameter. Size gas supply piping for total ﬂow to all connected appliances. For each GWC boiler, provide for the following gas ﬂow (cfh = cubic feet per hour):

Boiler model CFH natural gas

GWC-070 70

GWC-105 105

GWC-140 140

GWC-175 175

2. Inlet pressure required at gas valve inlet:

• maximum 14” w.c.

• minimum 3.5” w.c.

Install 100% lockup gas pressure regulator in sup-

ply line if inlet pressure exceeds 14” water column. Adjust for 14” w.c. maximum.

Propane Gas

1. Contact gas supplier to size pipes, tanks and 100% lockup gas pressure regulator.

2. Adjust propane supply regulator provided by gas supplier for 14” w.c. maximum pressure.

3. Inlet pressure required at gas valve inlet:

• maximum 14” w.c.

• minimum 3.5” w.c.

Figure 61 Pipe capacity for 0.60 speciﬁc gravity natural gas

Capacity in cubic feet of gas per hour

Gas pipe

length

(feet)

100

150

Natural gas only, with specic gravity of 0.60

Based on pressure drop of 0.3” w.c.

Gas pipe diameter —

½” ¾” 1” 1¼” 1½”

132 278 520 1050 1600

92 190 350 730 1100

73 152 285 590 860

63 130 245 500 760

56 115 215 440 670

45 93 175 360 545

38 79 150 305 460

31 64 120 250 380

Wiring

For your safety, turn off electrical power supply at

service entrance panel before making any electrical connections to avoid possible electric shock hazard. Failure to do so can cause severe personal injury or death.

Installation must comply with:

National Electrical Code and any other national, state, provincial or local codes or regulations. In Canada, CSA C22.1 Canadian Electrical Code Part 1, and any local codes. Boiler must be electrically grounded as required by National Electrical Code ANSI/ NFPA 70-latest edition.

Wiring must be N.E.C. Class 1. Boiler must be elec-

trically grounded as required by National Electrical Code ANSI/NFPA 70-latest edition.

To replace wiring, order complete harness assem-

blies from Williamson-Thermoﬂo. If any original wiring as supplied with boiler must be replaced, and a harness is not immediately available, use only type 105°C wire or equivalent. Use this wiring only as a temporary repair. Obtain a complete harness from Williamson-Thermoﬂo.

Wiring connections

Power wiring

Connect 120 VAC power wiring as shown in Figure 62. The junction box is located on the inside left jacket panel.

Watch the polarity of the circuit when connect-

ing the 120 VAC power wiring. If the polarity is switched, the integrated boiler control will lockout. The IBC will ﬂash the POWER light to indicate this problem. See the troubleshooting information beginning on page 74.

Additional limit controls

Wire additional limit controls (if used) as shown in Figure 63.

Thermostat(s)

Install thermostats on inside walls, away from inﬂuences of drafts, hot or cold water pipes, lighting ﬁxtures, television, sun rays, or ﬁreplaces.

Follow instructions with thermostat. If it has a heat anticipator, set heat anticipator in thermostat to match power requirements of equipment connected to it (ignition control and gas valve, zone valve contacts, etc.). Wiring diagram on boiler gives setting for standard equipment (ignition control and gas valve).

Thermostat wires are labeled “T-T” on boiler. Remove label before connecting as shown in Figure 62. Route this wiring through the hole in the upper left side jacket.

For zoned systems, substitute the zone valve end switches or circulator relay contacts for the thermostat contact shown in Figure 62.

For additional gas pipe sizing information, refer to ANSI Z223.1 (or B149.1 orB149.2 for Canadian installations).

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Wiring (continued)

Figure 62 Field wiring connections — service switch and thermostat (or end switch) provided by installer

DHW

Connect the DHW aquastat as shown in wiring above. The Economy function of the control is not utilized with DHW input.

R & C Connections

24 Vac should be used for power stealing thermostats only !

Other devices requiring 24 Vac should have separate power supply.

Wiring multiple zones

Refer to zone valve manufacturer’s literature for wiring and application. A separate transformer is required to power zone valves. Zoning with circulators requires a relay for each circulator.

When using three-wire zone valves, take care to

avoid mis-wiring. This can impose an additional 24 volts across the boiler control circuitry. The IBC will sense this problem and lockout. It will ﬂash the POWER and TSTAT CIRC lights to indicate the problem. See label on IBC for explanation of lockout conditions. To verify before connecting to boiler, disconnect ﬁeld thermostat wires at boiler. Place a voltmeter across the leads. Then watch the voltmeter as each zone is activated (by activating zone thermostat). There should never be a voltage reading across the two leads coming to the boiler. If you see a voltage reading, one or more zone valves is mis-wired.

Carbon monoxide detector

For Direct Exhaust units, a carbon monoxide de-

tector is required in the boiler room. The carbon monoxide detector must be wired on the same electrical circuit as the boiler. For Direct Vent units, a carbon monoxide detector that is wired on the same electrical circuit as the boiler is strongly recommended.

Figure 63 Wiring location for additional limit controls

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Wiring (continued)

Figure 64 Ladder wiring diagram

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Wiring (continued)

Figure 65 Schematic wiring diagram

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Start-up

Figure 67 Freeze protection guidelines

Freeze protection (when used)

Follow these guidelines to prevent possibility

of severe personal injury, death or substantial property damage:

NEVER use automotive or standard glycol antifreeze systems

recommended by Williamson-Thermoﬂo for application in GWC Boiler systems.

Thoroughly ush any system that has used glycol

boiler.

Review the material safety data sheet (MSDS)

owner and leave a copy for reference. The MSDS contains information on potential hazards and ﬁrst aid procedures for exposure or ingestion.

Check antifreeze inhibitor level at least annually

levels may change over time. Add antifreeze to increase concentration if necessary. Add inhibitor as needed to bring to acceptable level, using inhibitor test kit to verify.

, even glycol made for hydronic

. Use only freeze-prevention ﬂuids

before installing the new GWC

for the ﬂuid used with the boiler

. Glycol concentration and inhibitor

Eliminate all system leaks. Continual fresh makeup water

will reduce boiler life. Minerals can build up in sections, reducing heat transfer, overheating cast iron, and causing section failure.

Clean system to remove sediment

1. You must thoroughly ﬂush the system (without boiler connected) to remove sediment. Sediment can affect chemical treatment of the system and can damage system components.

2. For zoned systems, ﬂush each zone separately through a purge valve. (If purge valves and isolation valves are not already installed, install them to properly clean the system.)

3. Flush system until water runs clean and you are sure piping is free of sediment.

Water chemistry

Using softened water — Softened water can be corro-

sive. Pay special attention to the inhibitor level, following the instructions in this manual and those supplied with the inhibitor.

Failure to maintain water chemistry as speciﬁed can

Water chemistry must be within the limits listed in the following

water treatment company to set up a treatment program to control the system water within these limits at the time of initial ﬁll and throughout system operating life.

result in damage to the boiler and system components, resulting in potential for severe personal injury, death or substantial property damage.

. If the water differs in any way, consult a

When using freeze protection ﬂuid with au-

tomatic ﬁll,

water make-up

leak before the water begins to leak, causing concentration to drop, reducing the freeze protection level.

Part number 550-142-786/0712

DO NOT exceed 50% antifreeze by volume.

Antifreeze moves more sluggishly than water and can interfere with heat transfer. At antifreeze concentrations higher than 50%, sludge can develop in the boiler, potentially causing damage to the heat exchanger.

Clean the system before lling. Always

drain and ﬂush the system thoroughly before ﬁlling with antifreeze. Sludge, iron oxide deposits and other sediment in the system inhibit ﬂow and can cause rapid breakdown of inhibitors.

install a water meter to monitor

. Freeze protection ﬂuid may

Water pH: Minimum = 7.0 | Maximum = 8.5

1. Maintain boiler water pH between 7.0 and 8.5. Check with litmus paper or have chemically analyzed by water treatment company.

Hardness: Maximum = 6.0 grains per gallon

1. The water hardness must comply with the maximum value above. High hardness will cause scale accumulation.

Chlorine: Maximum 200 ppm

1. Filling with chlorinated fresh water should be acceptable since drinking water chlorine levels are typically less than 5 ppm.

2. Do not use the boiler to directly heat swimming pool or spa water.

3. Do not ﬁll boiler or operate with water containing chlorine in excess of 200 ppm.

Antifreeze

1. Use only antifreeze listed by Williamson-Thermoﬂo as suitable for use with GWC boilers. A list of approved antifreeze products is available at www.Williamson-Thermoﬂo.com.

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Start-up (continued)

2. See Replacement parts at the end of this manual for WilliamsonThermoﬂo part numbers to obtain antifreeze through a Williamson-Thermoﬂo distributor.

Use the correct amount of antifreeze

1. Determine the freezing temperature needed (to protect against lowest likely temperature the system water will encounter).

2. Find the antifreeze concentration by volume needed for this temperature from the antifreeze manufacturer’s data on the antifreeze container.

3. Add up the volume (gallons) of all system piping and components, including the expansion tank and boiler. a. Boiler water content is listed in Figure 106, page 100. b. Remember to include expansion tank water content.

4. Multiply this volume by the (percent) antifreeze needed to ﬁnd the number of gallons of antifreeze to add.

Fill and test water system

1. Fill system only after ensuring the water meets the requirements of this manual.

Purge air from water system

1. Connect a hose to the purge valve (see purge/drain valves in piping diagrams beginning with Figure 17, page 16. Route hose to an area where water can drain and be seen.

2. Close the boiler or system isolation valve between the purge valve and ﬁll connection to the system.

3. Close zone isolation valves.

4. Open quick-ﬁll valve on cold water make-up line.

5. Open purge valve.

6. One zone at a time, open the isolation valves. Allow water to run through the zone, pushing out the air. Run until no noticeable air ﬂow is present. Close the zone isolation valves and proceed with the next zone. Follow this procedure until all zones are purged.

7. Close the quick-ﬁll water valve and purge valve and remove the hose. Open all isolation valves. Watch that system pressure rises to correct cold-ﬁll pressure.

8. After the system has operated for a while, eliminate any residual air by using the manual air vents located throughout the system.

9. If purge valves are not installed in system, open manual air vents in system one at a time, beginning with lowest ﬂoor. Close vent when water squirts out. Repeat with remaining vents.

10. Open automatic air vent (diaphragm-type or bladder-type expansion tank systems only) one turn.

11. Starting on the lowest ﬂoor, open air vents one at a time until water squirts out.

12. Repeat with remaining vents.

Pressurize system

1. Close manual and automatic air vents and boiler drain valve.

2. Fill system to correct system pressure. Correct pressure will vary with each application. a. Typical cold water ﬁll pressure for a residential system is 12 psi

(when using a 30 PSIG boiler relief valve).

b. Pressure will rise when boiler is turned on and sys-

tem water temperature increases. Operating pressure must never exceed 5 PSIG less than the boiler relief valve setting.

3. At initial ﬁll and during boiler startup and testing, check system thoroughly for any leaks. Repair all leaks before proceeding further.

Eliminate all system leaks. Continual fresh

make-up water will reduce boiler life. Minerals can build up in sections, reducing heat transfer, overheating heat exchanger, and causing heat exchanger failure.

Use inhibitor supplied with boiler

1. The GWC boiler is shipped with Sentinel X100 inhibitor and Sentinel inhibitor test kit. See Replacement parts at the end of this manual for re-ordering information.

2. After ﬁlling the system as directed in these instructions, use a caulking gun to inject the X100 inhibitor into the system, following the instructions on the tube.

3. Inject all of the inhibitor supplied with the boiler. Allow time for the water to circulate and mix. Then check the inhibitor level. Add additional inhibitor if necessary.

Check/verify water chemistry

1. The system may have residual substances that could affect water chemistry.

2. After the system has been ﬁlled and leak tested, verify water pH and chlorine concentrations are acceptable.

3. Verify antifreeze concentration, when used.

4. Follow the instructions on the Sentinel test kit to sample the system water and verify inhibitor concentration.

Check inhibitor concentration annually

1. Test the pH of a sample of system water at least annually. The pH of the water mixture must be between 7.0 and 8.5. (Or use the Sentinel inhibitor test kit to check concentration.)

2. If pH is outside this range (or inhibitor test kit indicates low level), the inhibitor level may not be sufﬁcient to prevent corrosion.

3. Test antifreeze concentration.

Test antifreeze concentration at least annually.

If concentration is low, add antifreeze or drain system and reﬁll with correct mixture.

4. Follow instructions on antifreeze container to determine the amount of antifreeze needed. by volume concentration of antifreeze.

DO NOT exceed 50%

5. Check inhibitor level after adjustments are made.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Start-up (continued)

5. Once the external thermostat circuit wiring is checked

Check for gas leaks

and corrected if necessary, reconnect the external thermostat circuit wires. Allow the boiler to cycle.

Before starting the boiler, and during initial opera-

tion, use a leak detector or smell near the ﬂoor and around the boiler for gas odorant or any unusual odor. Remove boiler front door and smell interior of boiler enclosure. Do not proceed with startup if there is any indication of a gas leak. Repair any leak at once.

DO NOT adjust or attempt to measure gas valve

outlet pressure except where instructed speciﬁcally in this manual. This setting is suitable for natural gas and propane, requiring no ﬁeld adjustment. Attempting to alter or measure the gas valve outlet pressure without following the correct procedures could result in damage to the valve, causing potential severe personal injury, death or substantial property damage.

Propane boilers only — Your propane supplier

mixes an odorant with the propane to make its presence detectable. In some instances, the odorant can fade, and the gas may no longer have an odor. Before startup (and periodically thereafter), have the propane supplier verify the correct odorant level in the gas.

Verify gas/air oriﬁce plate

The proper orice plate must be used. Failure to do

so will cause severe personal injury, death or substantial property damage.

1. Remove the jacket front panel.

2. Read the boiler size written on the gas/air oriﬁce label tab, verifying the correct size. See Figure 5, page 8 for details.

3. The oriﬁce plate must be plain aluminum for natural gas. For propane gas, the exposed tab of the plate should be red.

4. Replace the oriﬁce plate if necessary, following the guidelines on page 8.

Inspect/ﬁll condensate system

Inspect/check condensate lines and ttings

1. Inspect the condensate drain line, condensate PVC ﬁttings and condensate trap.

Fill condensate trap with water

1. Loosen the hose clamp (Figure 66, item 2) that secures the condensate trap (Figure 66, item 1) to the bottom of the recuperator (Figure 66, item 3).

2. Pull the condensate trap tube off of the recuperator condensate drain nipple.

3. Use a funnel to feed water into the top of the condensate tube.

4. Continue ﬁlling until water begins to ﬂow out through the condensate line (Figure 66, item 4).

5. Re-attach the condensate trap to the bottom of the recuperator. Secure with the hose clamp.

6. Check for any leaks in the condensate drain line or ﬁttings. Repair any leaks.

7. Remove the temporary clamp (see step 2, above) from the condensate drain tube.

The condensate trap must be ﬁlled with water

during all times of boiler operation to avoid ﬂue gas emission from the condensate drain line. Prime the condensate trap by pouring water into the outlet tee while restricting ﬂow in drain tube if boiler has been out of service for an extended period. Failure to ﬁll the trap could result in severe personal injury or death.

Figure 66 Condensate trap assembly

Check thermostat circuit(s)

1. Disconnect the two external wires connected to the boiler thermostat terminals (see Field wiring, beginning on page 53 for terminal locations).

2. Connect a voltmeter across these two incoming wires. Close each thermostat, zone valve and relay in the external circuit one at a time and check the voltmeter reading across the incoming wires.

3. There should NEVER be a voltage reading.

4. If a voltage does occur under any condition, check and correct the external wiring. (This is a common problem when using 3-wire zone valves.)

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Start-up (continued)

Final checks before starting boiler

Review the boiler sequence of operation in Figure 71, page 64.



Verify that the boiler and system are full of water and all system



components are correctly set for operation.

High altitude locations (over 5,500 feet) — verify that the high



altitude pressure switch is installed per page 10.

Verify that condensate trap has been ﬁlled with water.



Verify electrical connections are correct and securely attached.



Inspect vent piping and air piping for signs of deterioration from



corrosion, physical damage or sagging. Verify air piping and vent piping are intact and correctly installed per this manual.

Adjust boiler control settings

BOILER OPERATING TEMPERATURE

With power turned on, control module receives a signal from the temperature sensor and displays boiler temperature. The control knob labeled BOILER TEMP is used to adjust the operating temperature setpoint, turning clockwise to increase temperature setting and counterclockwise to decrease. When the knob is turned to adjust temperature the display will brighten to indicate adjustment mode. After temperature is set to desired value, display will dim after approximately 5 seconds to indicate measurement mode.

•ADJUSTBOILEROPERATINGTEMPERATURETO 

DESIRED SETPOINT.

In accordance with Section 325 (f) (3) of the Energy Policy and Conservation Act, this boiler is equipped with a feature that saves energy by reducing the boiler water temperature as the heating load decreases. This feature is equipped with an override which is provided primarily to permit the use of an external energy management system

that serves the same function.

THIS OVERRIDE MUST NOT BE USED UNLESS AT LEAST ONE OF THE FOLLOWING CONDITIONS IS TRUE:

• An external energy management system is installed that reduces the boiler water temperature as the heating load decreases.

• This boiler is part of a modular or multiple boiler system having a total input of 300,000 BTU/hr or greater.

• This boiler is equipped with a tankless coil.

To start the boiler

1. Turn OFF the boiler ON/OFF switch.

2. Read and follow the Operating Instructions, Figure 72, page 65.

IMPORTANT

BOILER ECONOMY SETTING

To comply with Department of Energy regulations, the control module circulates available hot water before turning on the boiler to attempt to satisfy a call for heat. While attempting to satisfy the heat demand, the control module also monitors the boiler temperature changes via the temperature sensor and determines whether or not the available hot water will satisfy the demand, adjusting the time delay to turn on the boiler until it determines that additional heat will be needed. The knob labeled ECONOMY ADJUST provides an adjustment between maximize (MAX) and minimize (MIN) the delay. The maximum (MAX) adjustment position should be used to maximize energy savings. Turning the knob counterclockwise decreases the delay time and should only be used in the event that the heated space becomes uncomfortable.

• ADJUSTECONOMYTODESIREDPOSITION(MAXISTHE PREFERREDSETTING).

If boiler does not start correctly

1. Check for loose connections, blown fuse or service switch off?

2. Is external limit control (if used) open? Is boiler water temperature above boiler limit setting?

3. Is thermostat set below room temperature?

4. Is gas turned on at meter or boiler?

5. Is incoming gas pressure less than 4” w.c.?

6. If none of the above corrects the problem, refer to Troubleshooting, beginning on page 74.

Check system and boiler after start-up

 Check water piping

1. Check system piping for leaks. If found, shut down boiler and repair immediately. (See WARNING on page 58 regarding failure to repair leaks.)

2. Vent any remaining air from system using manual vents. Air in the system will interfere with circulation and cause heat distribution problems and noise.

 Check vent piping and air piping

1. Check for gas-tight seal at every connection and seam of air piping and vent piping.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Start-up (continued)

Figure 68 Check for igniter glow by looking into

observation port on front of blower housing

Venting system must be sealed gas-tight to prevent

ﬂue gas spillage and carbon monoxide emissions which will result in severe personal injury or death.

 Check gas piping

1. Check around the boiler for gas odor following the procedure of page 52 of this manual.

If you discover evidence of any gas leak, shut down

the boiler at once. Find the leak source with bubble test and repair immediately. Do not start boiler again until corrected. Failure to comply could result in severe personal injury, death or substantial property damage.

 Check the igniter

1. Inspect the igniter to verify operation as shown in Figure 68. The igniter glow may be difﬁcult to see clearly, depending on room lighting.

Gas valve adjustment — altitude over 5,500 feet ONLY

Apply the following only when:

• Altitude is over 5,500 feet above sea level.

• You have obtained a high altitude kit (with tools needed) and

installed high altitude air pressure switch per the instructions on page 10.

• Boiler has started correctly, following procedures on previous pages.

You will need the tools shown in Figure 69. Adjust the gas valve outlet pressure only if required as described in the following instructions.

Connect and adjust manometer

1. Remove boiler jacket top and front panels.

2. Close manual gas supply valve and turn off electrical power to boiler.

3. Using common bit screwdriver, remove outlet pressure tap plug from gas valve and save plug (Figure 70).

4. Place the negative side of the manometer hose over end of outlet pressure tap barrel.

5. Position and zero manometer per manufacturer’s instructions. The manometer must have at least 6” of tubing above the ﬂuid level or ﬂuid may be drawn into the gas valve.

If manometer ﬂuid is drawn into gas valve body, gas

valve must be replaced. Fluid in valve will cause it to malfunction, possibly resulting in severe personal injury, death or substantial property damage.

6. Disconnect tube from hose barb on gas valve vent tap. Connect tube end to tee hose ﬁtting as shown in Figure 70. Then add length of hose from tee hose ﬁtting to gas valve vent tap.

7. Connect positive side manometer hose to top of the tee hose ﬁtting (Figure 70).

8. Connect negative side manometer hose to the barrel of the gas valve outlet pressure tap (Figure 70).

Check gas valve setpoint

1. Open manual gas valve and turn on electrical power to boiler.

2. Start boiler and allow boiler to run for 5 minutes.

3. Read manometer. This is the gas valve outlet pressure set point. If set point is between – 0.1” w.c. and – 0.3” w.c. go to step 7.

4. If gas valve setpoint is not between – 0.1” w.c. and – 0.3” w.c., use T-40 driver to remove cap on gas valve pressure regulator.

5. Turn gas valve pressure regulator screw counter clockwise to lower gas valve set point to – 0.2” w.c.

6. Reinstall cap on gas valve pressure regulator using T-40 driver.

7. Cycle boiler off and on several times to verify gas valve set point. If set point does not remain between - 0.1” w.c. and – 0.3” w.c., readjust as necessary.

8. Close manual gas supply valve and turn off electrical power to boiler.

9. Remove manometer hose from gas valve outlet pressure tap barrel and replace sealing screw.

10. Remove tee hose ﬁtting and added tube.

11. Reinstall hose on gas valve vent tap hose barb.

12. Open manual gas supply valve and turn on electrical power to boiler.

Legend for Figure 70

1 Gas control outlet pressure tap — located on back side of gas control. Use

tap closest to gas control gas outlet —Remove screw from gas control outlet pressure tap and slide hose over tap

2 Add tee hose ﬁtting as shown

3 Existing hose to gas control vent tap hose barb — Remove from gas control

vent tap and connect to end of tee as shown

4 Gas control pressure regulator cap

5 Honeywell Type VK8115V gas valve

6 Gas outlet vent tap

7 Gas outlet piping

8 Add hose from gas control vent tap to tee hose ﬁtting

Part number 550-142-786/0712

3600 x 1000

= Btuh

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Start-up (continued)

Figure 69 Tools required for gas valve outlet pressure

measurement

1 U-tube manometer with tubing -

Manometer provides a ﬁne scale by slanting the manometer (Dwyer Model 1227 recommended).

2 Tee hose ﬁtting (provided in high

altitude kit).

Figure 70 Carefully connect manometer to gas valve as

shown, following instructions on this page (see legend at left)

/16" ﬂat head screw-

driver.

4 T-40 star drive for

gas valve pressure regulator cover screw.

Final checklist

Use the checklist following to ensure boiler is operating correctly.

Have the following been completed?

Is proper oriﬁce plate installed? Refer to page 8 to check size



and fuel type.

Proper oriﬁce plate must be used. Failure to do so

will cause severe personal injury, death or substantial property damage.

Thermostat heat anticipator (if available) set properly? Refer



to Field wiring, page 53.

Read and followed all procedures and checks speciﬁed in the



Start-up section, beginning with page 57?

Perform the following

Inspect vent system for leaks. Verify vent (and air) piping are



functional and unobstructed.

Measure natural gas input:



a. Operate boiler 10 minutes. b. Turn off other appliances. c. At natural gas meter, measure time (in seconds) required

to use one cubic foot of gas.

d. Calculate gas input:

number of seconds from step c

e. Btuh calculated should approximate input rating on

boiler rating label.

Test temperature limit — While burners are operating, turn



Boiler Temp adjustment knob counterclockwise until display reading is below actual boiler water temperature. Burners should go off while circulator continues to operate. Turn Boiler Temp adjustment knob clockwise until display reading is above boiler water temperature and ignition sequence should resume.

Test additional ﬁeld-installed controls — If boiler has a low



water cutoff, additional high limit or other controls, test for operation as outlined by manufacturer. Burner should be operating and should go off when controls are tested. When controls are restored, boiler should restart.

Test ignition system (integrated boiler control):



a. Connect voltmeter to gas valve terminals.

b. Turn off manual gas valve.

c. Set thermostat to call for heat.

d. IBC will begin purge cycle, then activate igniter. Igniter

will glow for approximately 20 seconds. Near end of 20 seconds, 24 VDC will show at gas valve for approximately

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Start-up (continued)

6 seconds and then return to 0 VDC. Control will attempt ignition two more times, increasing igniter time to 30 seconds for these attempts. The control will then lockout, ﬂashing the POWER and FLAME lights.

e. To restart system, follow Operating instructions on boiler

(also Figure 72, page 65). (Control will reset after power has been off for at least 45 seconds.)

Set Boiler Temp adjustment knob to system temperature re-



quirements. Adjust balancing valves and controls to provide design temperature to system.

Set Economy mode, fully clockwise.



Set Boiler temperature adjustment to system temperature



requirements. Adjust balancing valves and controls to provide design temperature to system.

For multiple zones, adjust ﬂow so it is about the same in each



zone or as required.

Cycle boiler with thermostat — Raise to highest setting and



verify boiler goes through normal start-up cycle. Lower to lowest setting and verify boiler goes off.

Cycle DHW Aquastat if used.



Observe several operating cycles for proper operation.



Set room thermostat to desired room temperature.



Fill in Installation and service certiﬁcate (see back cover of



manual).

Review all instructions shipped with this boiler with owner



or maintenance person. Return instructions to envelope and give to owner or place in pocket inside front panel in boiler.

Department of Energy - Compliance

This boiler is equipped with a control system that automatically adjusts a time delay period to turn on the boiler during a call for heat. This is accomplished by circulating available hot water in the system while measuring water boiler water temperature changes. The control calculates a suitable delay based on temperature measurements and turns the boiler on only after it determines that the demand for heat cannot be satisﬁed with the available hot water, Due to the wide variety of controls used in boiler installations, this control is also equipped with an adjustment for the calculated time delay period (ECONOMY ADJUST). In the MIN position, the time delay is zero and the IMPORTANT notice below must be observed:

IMPORTANT

system that serves the same function.

THIS OVERRIDE MUST NOT BE USED UNLESS AT LEAST ONE OF THE FOLLOWING CONDITIONS IS TRUE:

• An external energy management system is installed that reduces the boiler water temperature as the heating load decreases.

• This boiler is part of a modular or multiple boiler system having a total input of 300,000 BTU/hr or greater.

• This boiler is equipped with a tankless coil.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Start-up (continued)

Figure 71 Integrated boiler control (IBC) sequence of operation — status light indications

STEPS

(After Step 8, the cycle goes back to Step 1)

1. Standby

• Waiting for call for heat

2. Call for heat

• Circulator on

3. Limit circuit

• Limit controls closed

• Block switch contacts closed

• Blower on

4. Pressure circuit

• Pressure switch contacts closed

• Ignitor glows

5. Flame proven

• Gas valve open

• Ignitor remains on

Call for

Heat?

YES

YES 4 sec

POWER TSTAT

CIRC

LIMIT PRESS

SWITCH

FLAME

Timing

30 sec

—

6. Limit cycle

• Limit circuit open

• Gas valve closed

• Blower off after postpurge

7. Flame outage *

• Flame out

8. Thermostat satised

• Circulator off

• Blower postpurge

• Return to Step 1

* If ﬂame is not proven in 4 seconds, boiler recycles 2 times to retry for ignition before going into lockout. Recycle igniter timing

is 30 seconds. Postpurge and prepurge are performed on every cycle. In event of lockout, ignition control will automatically restore sequence of operation after either:

 •1hourwaitingperiod.

 •Openingandclosingofthermostatcircuit.

 •Removalof120VACpowerforatleast45seconds

YES

= ON

= OFF

30 sec

—

30 sec

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Start-up (continued)

Figure 72 Operating instructions

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Annual start-up and general maintenance schedule

Figure 73 Service and maintenance schedules

Service technician

(see following pages for instructions)

General:

• Addressreportedproblems,page67.

• Inspectboilerarea,page67.

• Inspectboilerinterior,page67.

• Inspectcondensatedrainsystem, page67.

• Inspectallpipingforleaks,page67.

• Inspectgaspiping,page67.

• Inspectthewatersystem,page67.

• Checkwatersystemchemistry,page67

• Inspectexpansiontank,page68.

• Inspectairopenings,page68.

• Inspectventsystemandairpiping, page68.

• Inspectboilerheatingsurfaces,page68.

• Inspectigniter,page68.

• Inspecttemperaturemixingsystem, page69.

• Inspectadditionalcontrolsandcutoffs, page69.

• Inspectgauges,page69.

• Inspectblowermotor,page69.

• Inspectoiled-bearingcirculators,page69.

Annnual start-up

• Inspecttemperaturesensor,page69.

• Inspectboilerreliefvalve,page70.

Owner maintenance

(see following pages for instructions)

• Checkboilerarea

Daily

Monthly

Periodically

Every 6 months

• Checkairopenings

• Checkpressuregauge

• Checkboilerinteriorpiping

• Checkventingsystem

• Checkairvents

• Checkcondensatedrainsystem

• Checkreliefvalve

• Testlowwatercutoff(ifused)

• Cleanventtermination/airintake screens

• Oilblowermotor

• Operatereliefvalve

Additional if combustion or performance indicates the need:

• FollowproceduresunderCleaningboiler heatingsurfaces,page71toaccessboiler componentslistedbelow.

• Cleanheatexchanger.

• Removeandcleanburnerusing compressedaironly.

• Vacuumtheblower.

Review:

• Reviewwithowner.

The boiler contains ceramic ﬁber

and ﬁberglass materials. Use care when handling these materials per instructions on page 106 of this manual. Failure to comply could result in severe personal injury.

End of season

Follow the service and maintenance procedures given throughout

• Shutdownprocedure

this manual and in component literature shipped with the boiler. Failure to perform the service and maintenance could result in damage to the boiler or system. Failure to follow the directions in this manual and component literature could result in severe personal injury, death or substantial property damage.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Annual start-up

Inspect all piping for leaks

Annual start-up only by qualiﬁed service technician

The boiler should be inspected and started annu-

ally, at the beginning of the heating season, only by a qualiﬁed service technician. In addition, the maintenance and care of the boiler designated in Figure 73, page 66 and explained on the following pages must be performed to assure maximum boiler efﬁciency and reliability. Failure to service and maintain the boiler and system could result in equipment failure.

Electrical shock hazard — Turn off power to

the boiler before any service operation on the boiler except as noted otherwise in this instruction manual. Failure to turn off electrical power could result in electrical shock, causing severe personal injury or death.

1. Inspect all water and gas piping and verify to be leak free.

2. Look for signs of leaking lines and correct any problems found.

3. Check gas line using procedure on page 52.

Inspect gas piping

1. Sniff near ﬂoor and around boiler area for any indication of a gas leak.

2. Test gas piping using bubble test, per page 52, if

there is any indication of a leak.

Eliminate all system or boiler leaks. Continual

fresh make-up water will reduce boiler life. Minerals can build up in sections, reducing heat transfer, overheating heat exchanger, and causing heat exchanger failure. Leaking water may also cause severe property damage.

Address reported problems

1. Inspect any problems reported by owner and correct before proceeding.

Inspect boiler area

1. Verify that boiler area is free of any combustible materials, gasoline and other ﬂammable vapors and liquids.

2. Verify that air intake area is free of any of the contaminants listed in Figure 36, page 30. If any of these are present in the boiler intake air vicinity, they must be removed. If they cannot be removed, reinstall the air and vent lines per this manual.

Inspect boiler interior

1. Remove jacket top and front door to inspect interior of boiler.

2. Vacuum any sediment and components.

Do not use solvents to clean any of the boiler compo-

nents. The components could be damaged, resulting in unreliable or unsafe operation.

Inspect condensate drain system

1. Inspect the condensate trap hose for deterioration.

2. Check for any obstructions in the trap hose by squeezing the tubing.

3. If there is any doubt the condensate drain system is ﬂowing freely, remove the clamp and hose from the bottom of the recuperator. Slide a funnel outlet into the trap hose and pour water through. It should exit at the termination of the condensate drain line.

Inspect the water system

1. Verify all system components are correctly installed and operational.

2. Check the cold ﬁll pressure for the system. Verify it is correct (usually around 12 PSIG).

3. Watch the system pressure as the boiler heats up (during testing) to ensure pressure doesn’t rise too high. Excessive pressure rise indicates expansion tank sizing or performance problem.

4. Inspect automatic air vents and air separators. Remove air vent caps and brieﬂy press push valve to ﬂush vent. Reinstall caps. Make sure vents do not leak. Replace any leaking vents.

Check water system chemistry

1. Check system water chemistry (pH and hardness). See instructions beginning on page 57.

2. Check glycol and glycol inhibitor levels if using glycol/ water mixture. See instructions beginning on page 57.

3. Check Sentinel X100 inhibitor level in the water using the Sentinel X100 Inhibitor Test Kit. Follow instructions supplied with the kit. Add X100 inhibitor if needed to bring to the correct level. (See Figure 93, page 88 for part numbers.)

Do not use petroleum-based cleaning or

sealing compounds in boiler system

vere damage to boiler will occur, resulting in substantial property damage.

. Se-

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Annual start-up (continued)

Inspect expansion tank

1. Expansion tanks provide space for water to move in and out as the heating system water expands due to temperature increase or contracts as the water cools. Tanks may be open, closed or diaphragm or bladder type. See page 13 of this manual for suggested location of expansion tanks and air eliminators.

• Open-type — located above highest radiator or baseboard unit,

usually in the attic or closet. Has a gauge glass and overﬂow pipe to a drain.

• Closed-type — welded gas tight and located above boiler. Tank is

partially ﬁlled with water, leaving an air cushion for expansion.

• Make sure this type of tank is ﬁtted with a tank ﬁtting, such as the B & G Tank-Trol or Taco Taco-Trol. This ﬁtting reduces gravity circulation of air-saturated tank water back to the system and prevents the air from bubbling up through the water as it returns from the system.

• Do not use automatic air vents in systems with closed-type tanks. The air will escape from the system instead of returning to the tank. Eventually, the tank will waterlog and no longer control pressurization. The boiler relief valve will weep frequently.

•

Diaphragm- or bladder-type — welded gas tight with a rubber

membrane to separate the tank pressurizing air and the water. May be located at any point in the system, but most often found near the boiler.

• Systems with this type of expansion tank require at least one automatic air vent, preferably located on top of an air eliminator, as shown in examples in this manual.

2. If relief valve has tended to weep frequently, the expansion tank may be waterlogged or undersized.

• Closed-type tank — tank is most likely waterlogged. Install a

tank ﬁtting if not already installed. Then check ﬁll level per ﬁtting manufacturer’s instructions. If ﬁll level is correct, check tank size against manufacturer’s instructions. Replace with a larger tank if necessary.

• Diaphragm- or bladder-type — ﬁrst, check tank size to be sure it

is large enough for the system. If size is too small, add additional tank (or tanks) as necessary to provide sufﬁcient expansion. If tank size is large enough, remove tank from system and check charge pressure (usually 12 PSIG for residential applications). If tank won’t hold pressure, membrane has been damaged. Replace tank.

Inspect air openings

1. Verify that combustion and ventilation air openings to the boiler room and/or building are open and unobstructed. Check operation and wiring of automatic combustion air dampers, if used.

2. Verify that boiler vent discharge and air intake are clean and free of obstructions.

Inspect vent system and air piping

1. Visually inspect entire ﬂue gas venting system and combustion air piping for blockage, deterioration or leakage. Repair any joints that show signs of leakage in accordance with vent manufacturer’s instructions. When air is ducted to boiler, verify that air inlet hose is connected and properly sealed.

Failure to inspect for the above conditions and have them

repaired can result in severe personal injury or death.

Figure 74 Igniter observation port in blower

Inspect boiler heating surfaces

The boiler contains ceramic ﬁber and

ﬁberglass materials. Use care when handling these materials per instructions on page 106 of this manual. Failure to comply could result in severe personal injury.

Electrical shock hazard — Turn off

power to the boiler before any service operation

otherwise in this instruction manual. Failure to turn off electrical power could result in electrical shock, causing severe personal injury or death.

1. Remove the jacket top panel and jacket front panel after turning off power to the boiler.

2. Remove the two nuts retaining the

spection port cover ueway inspection port cover.

3. Inspect the boiler vent outlet area and heating surfaces by looking through the opening.

4. If the boiler ﬂueways show accumulation of soot, follow

Cleaning boiler heating surfaces on

page 71 to remove the blower housing and clean the boiler. If there is evidence of a large accumulation of rusty scale deposits, check the temperature mixing system.

5. Replace the

ueway inspection port cover.

on the boiler except as noted

ueway in-

(page 3, item g). Remove the

Inspect igniter

1. Verify igniter operation — Look through blower observation port (see Figure 74). Access the blower by removing the boiler jacket front panel if not already removed

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Annual start-up (continued)

Inspect temperature mixing system

1. Carefully check the temperature of the system return piping as it passes through the boiler jacket and on the

the boiler jacket

do this with a surface pyrometer or by lightly touching the piping with your ﬁngers.

To avoid potential of severe burn — Do not rest hands

on or grasp pipes

may heat up quickly.

2. The temperature of the water entering the system should quickly heat up to about water from the system.

3. This is accomplished with the The Bypass circulator (page 2, item boiler supply outlet and blends it with return water. The System circulator (page 2, item temperature entering the sections.

4. If the

temperature mixing system does not work correctly, check

the two circulators to be sure they are ﬂowing water. If the circulators are operating normally but the temperature mixing system does not maintain water at the enterance to the boiler sections at 140°F, you may need to replace the boiler IBC or water temperature sensor (page 2, items

just before it enters the boiler sections. You may

. Use a light touch only. Return piping

140°F, being considerably hotter than the return

two internal boiler circulators.

7) takes hot water from the

6) slows down to aid in raising the return

1 and 8).

return pipe inside

Inspect additional controls and cutoffs

Figure 75 Blower motor

Inspect blower motor

1. See Figure 75. With boiler power OFF, place a few drops of Anderol 465 in each of the two oil cups.

Use only Anderol 465 to lubricate the blower

motor. Do not use universal household oils. Motor could be damaged, resulting in possible severe property damage.

1. Inspect and test the boiler additional controls. Verify operation by turning control set point below boiler temperature. Boiler should cycle off. Return dial to original setting.

2. Inspect and test additional limit controls or low water cutoffs installed on system. Follow the device manufacturer's instructions.

Inspect gauges

1. Boiler pressure/temperature gauge — Inspect gauge and check whether readings are reasonable. Replace if any signs of leakage from case or improper readings.

2. System gauges (if installed) — Inspect and check readings of other gauges in system.

Inspect oiled-bearing circulators

1. Both of the circulators installed in the boiler are waterlubricated. No oiling is required.

2. Check other circulators in the system. Oil any circulators requiring oil, following circulator manufacturer’s instructions. Over-oiling will damage the circulator.

Inspect temperature sensor

1. The temperature sensor may accumulate deposits on the probe surface. Annual inspection and cleaning of the probe will improve boiler performance.

Disconnect power, unplug harness from sensor. a. Drain boiler water to a level below the sensor. b. Remove sensor from boiler. c. Wipe any built up contaminates from probe and

insulator surfaces.

d. Reinstall sensor into boiler. Do not overtighten.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Annual start-up (continued)

Inspect boiler relief valve

1. Inspect the relief valve (Figure 76) and lift the lever to verify ﬂow as in the following warnings, excerpted from a relief valve manufacturer’s warning label. Before operating any relief valve, ensure that it is piped with its discharge in a safe area to avoid severe scald potential. Read page 12 before proceeding further.

Safety relief valves should be reinspected AT LEAST

ONCE EVERY THREE YEARS, by a licensed plumbing contractor or authorized inspection agency, to ensure that the product has not been affected by corrosive water conditions and to ensure that the valve and discharge line have not been altered or tampered with illegally. Certain naturally occurring conditions may corrode the valve or its components over time, rendering the valve inoperative. Such conditions are not detectable unless the valve and its components are physically removed and inspected. This inspection must only be conducted by a plumbing contractor or authorized inspection agency — not by the owner. Failure to reinspect the boiler relief valve as directed could result in unsafe pressure buildup, which can result in severe personal injury, death or substantial property damage.

Following installation, the valve lever must be

operated AT LEAST ONCE A YEAR to ensure that waterways are clear. Certain naturally occurring mineral deposits may adhere to the valve, rendering it inoperative. When manually operating the lever, water will discharge and precautions must be taken to avoid contact with hot water and to avoid water damage. Before operating lever, check to see that a discharge line is connected to this valve directing the ﬂow of hot water from the valve to a proper place of disposal. Otherwise severe personal injury may result. If no water ﬂows, valve is inoperative. Shut down boiler until a new relief valve has been installed.

2. After following the above warning directions, if the relief valve weeps or will not seat properly, replace the relief valve. Ensure that the reason for relief valve weeping is the valve and not over-pressurization of the system due to expansion tank waterlogging or under-sizing.

Figure 76 Relief valve

To complete Annual Start-up, perform startup and checks:

1. COMPLETE the annual start-up procedures beginning on page 67.

2. Start boiler and perform checks and tests speciﬁed in this manual.

3. Verify cold ﬁll pressure is correct and that operating pressure does not go too high.

4. Complete the check-out procedure on page 62.

Review with owner

1. Review the User’s Information Manual with the owner.

2. Emphasize the need to perform the maintenance schedule specified in the User’s Information Manual (and in this manual as well).

3. Remind the owner of the need to call a licensed contractor should the boiler or system exhibit any unusual behavior.

4. Remind the owner to follow the proper shutdown procedure and to schedule an annual startup at the beginning of the next heating season.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Service & maintenance

Cleaning boiler heating surfaces

The service procedures in this manual

must only be performed by a qualiﬁed boiler service technician. Failure to comply could result in severe personal injury, death or substantial property damage.

The boiler contains ceramic ﬁber and

ﬁberglass materials. Use care when handling these materials per instructions on page 106 of this manual. Failure to comply could result in severe personal injury.

1. If inspection of the boiler ﬂueways indicates the presence of soot, cl

following procedure. The process requires removing the blower housing to allow spraying water through the boiler combustion chamber.

2. Before proceeding, obtain a GWC gasket replacement kit, consisting of igniter, recuperator, ﬂueway inspection port and blower ﬂange gaskets.

To remove the blower assembly

1. Turn off boiler by turning down the thermostat. Then turn off power at the boiler service switch. Close manual gas valve on incoming gas line to boiler.

ean the boiler heating surfaces using the

Turn off power and gas to the boiler.

Failure to do so can cause severe personal injury, death or substantial property damage.

Figure 77 Blower housing removal procedure

Wait several minutes after boiler has

stopped to allow the igniter to cool to avoid severe personal injury or death.

2. See Figure 77.

3. Disconnect: a. Remove union outside of boiler b. Gas tubing from gas valve outlet by removing

the 4 screws securing the outlet ﬁtting to the

valve. (Save the o-ring in the ﬁtting.) c. Remove gas valve and bracket d. Hose from gas valve to gas/air manifold e. Pressure switch hoses f. Air inlet hose g. Blower motor wiring harness from IBC h. Igniter harness connected to igniter plug i. Blower support bracket (remove screw secur-

ing blower housing to bracket — on left side of

blower housing) j. Ground wire.

4. Remove the two igniter screws and washers. Carefully remove the igniter. Use care when handling — igniter is very brittle. DO NOT touch igniter surface with hands or expose to any greasy substances.

5. Remove nuts from studs securing blower housing to front section.

1 Blower assembly

2 Blower support bracket

3 Blower motor wiring harness

4 Air pressure switch

5 Blower ﬂange gasket (

6 Burner cone and ring assembly

7 Igniter gasket (

replace this)

8 Gas/air oriﬁce plate

9 Red pressure switch hose

10 White pressure switch hose

11 Inlet air hose and clamps

12 Gas tubing

13 Igniter

14 Gas valve and bracket

6. Grasp blower housing and pull free from studs. Turn clockwise slightly, until blower assembly can be removed safely from inside of boiler jacket.

7. Remove burner cone and gasket for inspection.

To clean heating surfaces

1. Remove the ﬂueway inspection port cover (page 3, item g), if not already off of the boiler.

2. Place a catch pan under the inspection port to catch the cleaning water.

3. Spray water into the boiler combustion chamber opening.

4. Catch the runoff water in the pan below the inspection port.

5. Continue process until ﬂueways are clean.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Service & maintenance (continued)

To clean the burner

The burner may contain ceramic ﬁber particles. Use

care when handling these materials per instructions on page 106 of this manual. Failure to comply could result in severe personal injury.

1. Clean the burner ports with a soft brush.

2. Use compressed air to blow out any particulate if necessary. Use caution to avoid particulate being blown into the building.

To replace blower assembly

1. Place a new blower ﬂange gasket over the studs at combustion chamber opening.

2. Reinstall burner cone into chamber opening.

3. Position blower assembly over studs. Install nuts and tighten.

4. Install igniter and new igniter gasket. Fasten with screws and washers. Tighten only with hand-held screwdriver. DO NOT use electric or pneumatic driver. Excessive torque will damage igniter. Do not exceed 20 inch-pounds torque.

5. Connect: a. Gas valve and piping (4 screws) b. Gas tubing to gas valve outlet c. Pressure switch hoses d. Hose from gas valve to gas/air manifold e. Air inlet hose f. Blower motor wiring harness to IBC g. Igniter harness to igniter plug h. Blower support bracket (with screw) i. Ground wire.

6. Be sure all wiring and hose connections are correct per Figure 77, page 71 and are secure on the hose barb ﬁttings.

Inspecting and cleaning the recuperator

Turn off power and gas to the boiler. Failure to

do so can cause severe personal injury, death or substantial property damage.

Wait several minutes after boiler has stopped to al-

low the boiler components to cool to avoid severe personal injury or death.

Removing/cleaning/re-installing the recuperator

Disconnect the vent pipe from the recuperator

1. The vent pipe must be disconnected (at the in-line ﬂue drain, item A in Figure 7, page 9).

2. If the vent piping can be moved enough, loosen the ﬂue pipe clamp on the in-line ﬂue drain. Then lift the ﬂue pipe up and move aside slightly.

3. If the vent piping cannot be moved, then cut the ﬂue pipe carefully so a coupling can be inserted later, or remove a section of vent pipe if using stainless vent pipe.

Figure 78 Recuperator access and cleaning

Isolate boiler and drain partially

1. Remove the jacket top panel and front panel.

2. Allow time for the boiler to cool down if it has been operating.

3. Close the isolation valves on the boiler supply and return connections.

4. The boiler will have to be partially drained. a. Place a large pan under the boiler drain valve. b. Slowly open the drain valve and allow about a gallon of

water to drain out.

c. Place the pan under the water connection ﬂanges on the

recuperator.

d. Loosen the upper recuperator ﬂange and allow any water

in the line to run out.

e. Loosen the lower recuperator ﬂange (return connec-

tion) and allow the water in the line and recuperator to drain out.

5. After the recuperator and water lines have been drained, disconnect both recuperator ﬂanges.

Remove the recuperator

1. See Figure 99, page 94. Loosen the (4) nuts that secure the recuperator to the boiler.

2. Disconnect the plug-in connector on the thermal fuse (Figure 99, page 94, item 27).

3. Carefully slide the recuperator off of the (4) studs.

4. Loosen the ﬂue adapter clamp and remove the in-line drain ﬁtting from the ﬂue adapter.

5. Flush the ﬂueway (Figure 78, item 1) and tubes (Figure 78, item 2) thoroughly with fresh water, allowing the water to drain out through the recuperator condensate opening.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Service & maintenance (continued)

Figure 79 Recuperator ﬂueway drain holes

6. Dump any remaining water from the recuperator.

7. Look through the ﬂue adapter and locate the ﬂueway drain holes as shown in Figure 79.

8. Use a brush or other means to remove blockage from these holes.

9. Rinse the recuperator thoroughly.

Make sure the recuperator access cover and the

condensate trap are re-installed securely.

Failure to comply with the above could result in

severe personal injury, death or substantial property damage.

Re-connect the vent pipe

1. If the vent pipe was lifted out, re-insert the vent pipe into.

2. If the vent pipe was cut, install a coupling in the vent line to allow re-connection.

3. If a section was removed (stainless vent pipe), replace the section.

4. Re-connect the vent pipe to the in-line drain ﬁtting and tighten the clamp.

When replacing the vent pipe, follow all instruc-

tions in this manual to ensure the vent is properly completed. Failure to properly the vent pipe could result in severe personal injury, death or substantial property damage.

Re-install the recuperator

1. Inspect the recuperator gaskets to make sure all are in good condition. Replace if there is any sign of damage.

2. Attach the recuperator at the boiler connection.

3. Secure with the four nuts.

4. Re-connect the water connections to the upper and lower recuperator ﬂanges.

5. Re-insert the in-line drain ﬁtting into the recuperator vent adapter. Tighten the clamp to secure in place.

6. Re-connect the plug-in connector on the thermal fuse (Figure 99, page 94, item 27).

Re-install the condensate trap and recuperator access cover

1. Replace the condensate trap and recuperator access cover — tighten bolts securely (do not exceed 18 inch-pounds, 2 N-m, torque).

If the recuperator shows signs of significant

corrosion or deterioration, contact WilliamsonThermoﬂo for recommendations on investigating the cause and replacing the recuperator if necessary.

Make sure the recuperator access cover gasket is in

good condition. Replace if necessary.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting

VERIFY PROPER OPERATION AFTER SERVICING.

Label all wires prior to disconnection when servicing

controls. Wiring errors can cause improper and dangerous operation.

Never jumper (bypass) any device except for momentary

testing as outlined in Troubleshooting charts. Severe personal injury, death or substantial property damage can result.

The IBC and boiler controls can malfunction if they get

wet. Never try to use a control that has been ﬂooded or wet. Replace it. Failure to comply can result in severe personal injury, death or substantial property damage.

The boiler contains ceramic ﬁber and ﬁberglass materials.

Use care when handling these materials per instructions on page 106 of this manual. Failure to comply could result in severe personal injury.

Before troubleshooting

1. Have a voltmeter that can check 120 VAC, 24 VAC, 24 VDC and a continuity checker.

2. Check for 120 VAC (min. 102-max.132) to boiler.

3. Make sure thermostat is calling for heat and contacts (including appropriate zone controls) are closed. Check for 24 VAC between thermostat wire nuts and ground.

4. Have an inclined manometer with 0 – 2” w.c. range.

Figure 80 Connecting a manometer to check

air pressure switch. DO NOT use this arrangement to check gas valve

Check the following

1. Wire connectors to IBC are securely plugged in at IBC and originating control.

2. Hoses are properly and securely plugged in and are not damaged.

Checking the air pressure switch

Do not use manometer as shown in Figure 80 to test gas

valve outlet pressure. Where instructed in this manual to check gas valve outlet pressure, follow instructions carefully, particularly regarding connection of manometer. Manometer ﬂuid will cause permanent damage to gas valve. Severe personal injury, death or substantial property damage can result.

Check switch pressure setting

1. See Figure 80.

2. Remove both air pressure switch hoses from air pressure switch.

3. Install tees and tubing as shown in Figure 80 to inclined manometer.

4. Turn off gas valve and set thermostat to call for heat. Blower will run but burner will not ignite.

5. Check for 24 VAC between both air pressure switch terminals and ground.

6. If manometer reading is at least 1.0” w.c., but there is not 24 VAC between both air pressure switch terminals and ground, replace air pressure switch.

Troubleshooting air pressure reading

1. If manometer reading is lower than 1.4” w.c. check for possible causes:

• Blockage in hoses.

• Loose blower wheel on motor shaft.

• Blower motor not at proper rpm.

• Blockage in air inlet or hose.

• Blockage in ﬂue pipe or termination.

• Condensate trap ﬁlled w/condensate.

Return to normal operation

1. When pressure reading is proper and air pressure switch is operating properly, remove tees and reinstall hoses to air pressure switch.

Part number 550-142-786/0712

85060

85062

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting (continued)

Igniter

Wait several minutes until igniter cools down before at-

tempting replacement. Failure to do so will cause severe personal injury.

1. Disconnect igniter (Figure 81) from igniter wiring harness and remove igniter before removing from blower assembly.

2. Replace igniter gasket if original gasket is frayed or damaged OR if room-temperature resistance across igniter is not between 40 and 95 ohms.

3. Igniter is fragile — handle with care. Do not touch igniter surface with bare hands. Body oils can cause failure of the carbide.

Gas Valve

The gas valve (Figure 82) operates with a negative pres-

sure at the outlet — approximately –0.2” w.c. — DO NOT set gas pressure higher than this.

Follow instructions in this manual carefully if testing

gas valve outlet pressure. Failure to comply can result in severe personal injury or death.

The gas valve outlet is bolted to the gas line adapter and

sealed with an o-ring. When replacing valve, replace only with valve listed in this manual for use with the GWC boiler. Failure to comply could result in severe personal injury, death or substantial property damage.

Figure 81 Igniter

Figure 82 Gas valve

Figure 83 Blower housing

Blower Housing

Do not disassemble blower housing (Figure 83). A

ﬁre or explosion causing severe personal injury, death or substantial property damage can result. If you suspect a problem, replace blower housing. Follow instructions on page 71 for blower housing removal and replacement.

Thermal fuse

1. The thermal fuse (Figure 84) protects vent pipe from excess ﬂue temperatures.

2. If the thermal fuse opens, it must be replaced. See page 93 for replacement information.

If the thermal fuse opens, investigate the cause before

replacing switch and starting the boiler. DO NOT attempt to jumper the switch. Failure to comply could result in severe personal injury, death or substantial property damage.

Figure 84 Thermal fuse

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting (continued)

Return temperature sensor

1. See Figure 85.

Figure 85 Return temperature sensor

2. Resistance check method:

a. With the boiler operating, use a contact thermometer to

measure the temperature of the return pipe next to the return temperature sensor. Make a note of the temperature.

b. Turn the boiler ON/OFF switch off.

c. Immediately disconnect the return temperature sensor

plug from the IBC.

d. Measure the resistance of the sensor. Write down the

result.

e. Let the sensor cool to room temperature and measure the

resistance again. Write down the result.

f. Compare the sensor resistances at both temperatures to

the closest temperatures in Figure 86.

Supply temperature sensor

1. See Figure 87 .

2. The boiler temperature sensor is a resistance-type device.

3. The Figure 88 below shows the correct value for the sensor at various temperatures.

4. Use the resistance values at 32°F, 60°F, 70°F and 212°F to measure the sensor resistance at known temperatures (ice point, room temperature and sea level boiling point). For ice point and boiling point, insert the sensor in water at that temperature. Use an ohmmeter to read resistance value between thermister # and thermistor common. See Figure 93 page 79, for sensor plug details.

Figure 87 Supply temperature sensor

Figure 86 Return temperature sensor resistance

Temperature °FResistance

Ohms

60 15300 140 2480

70 11900 160 1680

80 9310 180 1160

100 5840 200 810

120 3760 212 674

Temperature °FResistance

Ohms

g. If the measured values are within 10% of the values listed,

the sensor is good. If not, replace the sensor. See Replacement parts for the part number.

3. Fixed resistor method a. With the boiler power OFF, disconnect the return tem-

perature sensor plug at the IBC.

b. Insert a 2500-ohm resistor into the IBC sensor plug.

c. Restart the boiler.

d. If the boiler operates with the resistor, but not with the

sensor, try replacing the sensor. See Replacement parts for the part number.

Figure 88 Supply temperature sensor resistance

Sensor resistance values

Temp

(°F)

100

110

Sensor ohms

Min Max Min Max

34265 37871

27834 30764

21630 23907

16944 18727

13372 14780

10629 11747

8504 9399

6847 7568

5545 6129

Temp

(°F)

120

130

140

150

160

170

180

190

200

Sensor ohms

4517 4992

3698 4088

3043 3364

2517 2782

2091 2311

1744 1928

1461 1615

1229 1359

1038 1147

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting (continued)

Figure 89 GWC Integrated Boiler Control (IBC)

IBC (integrated boiler control)

Make sure ground wiring is installed per wiring

diagram. Good grounding is extremely important for proper operation.

Control indicator lights —

HARDLOCKOUTSummary(FlashingLED’s)

MAY remove 120VAC power for more than 2 seconds to clear lockout OR ignition control will automatically restart sequence of operation after 1 hour waiting period after fault condition is cleared.

INDICATORLIGHT CONDITION POWER

Flashes once per second 120 VAC connection to boiler reversed.

Flash code 2* Internal fault, microprocessor or memory.

Flash code 3* Unused.

Flash code 4* Unused.

Flash code 5* Internal fault, water thermistors disagree.

Flash code 6* Internal fault, gas valve circuit.

* Flash code pattern: POWER LED ashes 2, 3, etc. times rapidly

followed by 2 seconds off, then repeats.

POWER light ashing alone

• Usually indicates reversed polarity of 120 VAC power wires.

POWER and TSTAT/CIRC lights ashing

• Usually indicates stray voltage on external thermostat circuit wires or return water temperature entering boiler sections has not reached 130°F within 30 minutes.

POWER and PRESS SWITCH lights ashing

• Usually indicates pressure switch is closed when it should not be, or pressure switch failed to close within 5 minutes of blower starting.

Solder or water splatter between

plugs and circuit board can cause improper operation of IBC. Place a shield over the boiler internal controls and components during installation. Failure to comply could result in severe personal injury, death or substantial property damage.

IBC indicator lights — lockout modes

• See Charts 1 through 7 in this section for detailed trouble-shooting procedures.

• To reset control after a lockout, turn off power at the 120 VAC service switch or turn down all thermostats. Wait 45 seconds. Then restore power and call for heat.

• After an over-temperature lockout (POWER and LIMIT lights ﬂashing), the control will only reset after interruption of 120 VAC for 45 seconds. (And temperature at return water temperature sensor must be below 240°F.)

POWER and FLAME lights ashing

• Usually indicates control has had three unsuccessful ignition attempts or sensed ﬂame when it shouldn’t be there. Boiler may not be properly grounded.

IBC indicator lights — non-lockout modes

TSTAT/CIRC light ashing alone

• Usually indicates return water temperature sensor detects water at boiler return pipe less than 40°F. Both internal circulators will run continuously, even with no call for heat, until temperature rises.

LIMIT light ashing alone

• Usually indicates an open or shorted return or supply water temperature sensor.

Troubleshooting the IBC

• See Figure 90, page 78 for location of harness plug receptacles and plugs on the IBC.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting (continued)

Figure 90 IBC harness plug receptacle and indicator light locations

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting (continued)

Figure 91 Common causes and possible corrections, part 1

Symptom Common Causes Possible Corrections

Rapid cycling — boiler turns on and off frequently

Frequent release of water through relief valve

Thermostat installed where drafts or heat affect reading

Heat anticipator in thermostat adjusted incorrectly

Incorrect limit setting Set limit according to system needs.

Insufﬁcient water ﬂow through boiler

Expansion tank sized too small Call qualiﬁed service technician to check

Flooded expansion tank Call qualiﬁed service technician to check

Locate thermostat on inner wall away from heat sources or cool drafts.

Adjust thermostat per manufacturer’s instructions.

Maximum setting is 200°F. Increase limit setting to decrease cycling.

Check all valves to and from boiler. Return to proper setting.

Conﬁrm circulator size.

expansion tank operation and size.

expansion tank operation.

Need to frequently add makeup water

Black water condition

Large temperature swings in living space

Part number 550-142-786/0712

Inoperative limit control Call qualiﬁed service technician to replace

limit control.

Leaks in boiler or piping Have qualiﬁed service technician repair

leaks at once to avoid constant use of makeup water. Makeup water can cause mineral deposits which, in turn, can cause boiler section failure. Do not use petroleumbase stop-leak compounds.

Oxygen corrosion due to leaks in boiler and piping

Incorrect Economy setting Adjust Economy setting on boiler control.

Have qualiﬁed service technician repair at once. Keep pH of water between 7.0 to 8.5.

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting (continued)

Figure 92 Common causes and possible corrections, part 2

Symptom Common Causes Possible Corrections

Popping or percolating noise heard in boiler

Metal ﬂakes found in vent outlet or recuperator — ﬂueway corrosion

Mineral deposits in sections due to constant use of makeup water

Incorrect pH of boiler water Call qualiﬁed service technician to check

Insufﬁcient water ﬂow through boiler

Contaminated combustion air supply — See manual page 30.

Call qualiﬁed service technician to delime boiler, if necessary. In some cases, deposits will be too heavy to remove with de-liming procedures.

Have qualiﬁed service technician repair leaks to eliminate need for constant makeup water.

pH level and correct. pH should be maintained between 7.0 to 8.5.

Check all valves to and from boiler. Return to proper setting.

Conﬁrm circulator size.

Remove any contaminating products, see manual page 30.

Some radiators or baseboard units do not heat or are noisy

Provide outside air for combustion. Have qualiﬁed service technician pipe-up kit.

Condensation of combustion gases in boiler sections

Air in system Bleed air from system through air vents in

Low system pressure Fill to correct pressure.

High limit set too low Adjust high limit to higher setting.

Have qualiﬁed service technician check operation of mixing system. Repair/replace if necessary.

radiators or baseboard units.

Check for leaks in boiler or piping. Have qualiﬁed service technician repair at once.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting (continued)

CHART 1

No Ye s

Flashing

alone?

TSTAT/CIRC

light ﬂashing

PRESS SWITCH

light ﬂashing

FLAME

light ﬂashing

NO LIGHT IS

FLASHING,

but there is

insufﬁcient heat

Troubleshooting POWER light status

Electrical shock hazard — Wherever you see TURN OFF POWER, follow the instructions. Failure to follow instructions could result in severe personal injury, death or substantial property damage.

Is POWER light off?

Is POWER light . . .

Flashing with another light?

CHART 2,

page 82

CHART 3,

page 83

CHART 4,

page 84

On steady

(NOT ﬂashing)?

CHART 5,

page 85

CHART 6,

page 86

CHART 7,

page 87

• Make sure service switch or circuit breaker is on or fuses are good.

• Remove 120 VAC IN plug (Figure 90, page 78, Item 1) on IBC.

• Using voltmeter, check across top and bottom pins of 120 VAC IN receptacle.

Does voltmeter indicate 120 VAC?

No Ye s

Problem is with incoming electricity. Have licensed electrician repair circuit.

• Reconnect 120 VAC IN plug.

• Remove 120 VAC transformer PRIMARY plug

(Figure 90, page 78, Item 2) on IBC.

• Using voltmeter, check across top and bottom pins of PRI- MARY receptacle.

Does voltmeter indicate 120 VAC?

No Ye s

• Usually indicates polarity on incoming 120 VAC power line is wrong.

• TURN OFF POWER at service switch or breaker, then reverse the HOT and NEUTRAL wires entering the boiler in the J-box.

• Restore POWER at service switch or breaker.

Is POWER light ﬂashing now?

No Ye s

Boiler should now operate normally.

Part number 550-142-786/0712

Have system checked by a licensed electrician.

If problem persists, call your local Williamson-Thermoﬂo sales representative.

Replace IBC. Retest

• Reinstall 120 VAC transformer PRIMARY plug.

• Remove 24 VAC transformer plug (Figure 90, page 78,

Item 7) on IBC.

• Using voltmeter, check across pins of receptacle.

Does voltmeter indicate 24 VAC?

No Ye s

Replace transformer. Retest.

Replace IBC.

Retest.

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting (continued)

CHART 2

Electrical shock hazard — Wherever you see TURN OFF POWER, follow the instructions. Failure to follow instructions could result in severe personal injury, death or substantial property damage.

Is return water temperature sensor clamped

securely to the return pipe in the boiler?

Ye s No

• Check for stray voltage on the incoming thermostat wires. Disconnect the two external wires connected to the boiler thermostat wires.

• Connect a voltmeter across the two incoming wires. Close each thermostat, zone valve and relay in the external circuit one at a time and check the voltmeter reading across the wires. There should NEVER be a voltage reading. If a voltage does occur

Did you ﬁnd and correct a voltage across the two external thermostat circuit wires?

Ye s No

• Boiler should now operate per the normal sequence of operation (Figure 71, page 64) if wiring was corrected.

TSTAT/CIRC & POWER lights ﬂashing

• Attach sensor to pipe with clamp provided.

• Follow return temperature sensor checking procedure

on page 76. Replace sensor if necessary.

• Retest.

under any condition, check and correct the external wiring. (This is a common problem when using 3-wire zone valves.)

• Once the external thermostat circuit wiring is checked and corrected if necessary, reconnect the external thermostat circuit wires to the boiler thermostat wires and allow the boiler to cycle.

Is boiler internal Bypass circulator operating?

No Yes

• Remove CIRCULATORS plug (Figure 90, page 78, Item 4)

from plug receptacle of IBC.

• Place voltmeter leads across the right-side 120 VAC N and

120 VAC H pins of the CIRCULATORS receptacle.

Does the voltmeter indicate 120 VAC?

No Ye s

• Replace IBC.

• Retest.

• Replace circulator harness.

• Retest.

• Reconnect circulator harness to IBC.

• Attempt to get the circulator started by giving it a sharp rap

on the end of the circulator motor (to release a possibly locked impeller).

• If the circulator begins to operate, allow it to operate for a few minutes to see if the problem clears.

• If problem persists, replace the Bypass circulator.

• Retest.

• Test wire continuity of

circulator wire harness.

Is harness ok?

No Ye s

• Check the boiler internal return pipe where it enters the

boiler sections. The TSTAT/CIRC and POWER lights will ﬂash after 30 minutes as long as the return water temperature is less than 130 °F.

• Wait up to 20 minutes to give the boiler and system a chance to respond.

Does problem persist?

No Yes

• Boiler may now be operating normally. Verify against normal sequence of operation (Figure 71, page 64).

• If boiler appears not to be heating, troubleshoot boiler per CHART 7, page 87. If problem cannot be resolved, replace water temperature sensor and retest. Then replace IBC (IBC) if sensor does not correct the problem.

• If boiler is heating, but the temperature at the return pipe does not increase above 130 °F, there may be an incorrectly-piped external circulator forcing water through the boiler. Check external piping and correct.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting (continued)

CHART 3

Electrical shock hazard — Wherever you see TURN OFF POWER, follow the instructions. Failure to follow instructions could result in severe personal injury, death or substantial property damage.

• Reset boiler control by turning off power at service switch or turning down thermostat for at least 45 seconds.

No Ye s

• Remove BLOWER plug (Figure 90, page 78, Item 3) from plug receptacle of IBC.

• Place voltmeter leads across the 120 VAC N and 120 VAC H pins of the BLOWER receptacle.

Does the voltmeter indicate 120 VAC?

No Ye s

PRESS SWITCH & POWER lights ﬂashing

Does blower motor operate?

• Thermostat should call for heat and appropriate zone valves open.

Is blower wheel turning at speed of blower motor?

No Ye s

• TURN OFF POWER at

service switch.

• Properly position blower wheel on blower motor shaft and tighten set screw. (Or replace blower housing assembly.)

• Retest.

• Wait 5 minutes.

Is purge light ﬂashing?

No Ye s

• TURN OFF POWER at service switch.

Does blower wheel turn freely by hand?

No Ye s

• Properly position blower wheel on blower motor shaft and tighten set screw. (Or replace blower housing assembly.)

• Retest.

• Remove one of the red wires connected to the pressure

switch.

• Check continuity across the switch terminals.

Does the ohmmeter indicate the switch is closed?

No Ye s

• Replace IBC.

• Retest.

• Check air pressure switch per page 74.

• Replace if necessary.

• Retest.

• Replace blower motor.

(Also check blower housing assembly. Replace if necessary.)

• Retest.

• Boiler should be in normal operating se-

quence (Figure 71, page 64).

• Observe operation until thermostat is satisﬁed and blower has completed its postpurge cycle.

• Check condensate trap.

Is blower wheel turning at speed of blower motor?

Is there condensate present?

No Ye s No Ye s

Are vent or combustion air

passages blocked?

No Ye s

• Clear passages and recycle boiler.

• Recheck boiler operation.

• Drain condensate.

• Retest.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting (continued)

CHART 4

Electrical shock hazard — Wherever you see TURN OFF POWER, follow the instructions. Failure to follow instructions could result in severe personal injury, death or substantial property damage.

Are manual main shutoff valve and gas valve turned on?

No Ye s

• Open manual gas valve.`

• Restart boiler, following Operating instructions on boiler

(see Figure 72, page 65).

• Check for proper operation (per normal sequence of operation).

• Replace IBC.

• Retest.

FLAME & POWER lights ﬂashing

• Check gas valve harness wires and check for tight wiring connections on gas valve and IBC. Repair/replace as necessary.

• Recycle boiler by thermostat or service switch (holding power off for at least 45 seconds).

• Thermostat should call for heat and appropriate zone valves close.

During step 5 of normal sequence of operation (Figure 71, page 64),

is there 24 VAC across gas valve terminals?

No Ye s

• Remove inducer/gas valve assembly. Clean burner cone insuring no debris is in between inner and outer cone. Remove gas manifold from gas valve and inducer. Run a small wire through manifold to remove spider webs. Check gas entry hole in bottom of inducer for possible debris or bugs and clean thoroughly.

• Check and/or replace igniter, if cold resistance is not between 40-75 ohms. Recycle boiler by thermostat or service switch. Thermostat should call for heat and appropriate zone valves close.

• Wait 5 minutes.

Are FLAME & POWER lights ﬂashing?

No Ye s

• Boiler should now operate normally.

• Original ﬂashing FLAME light caused by igniter not

operating properly.

• See normal sequence of operation (Figure 71, page 64).

• Boiler should now operate normally.

• Original ﬂashing FLAME light caused by gas valve not

operating properly.

• See normal sequence of operation (Figure 71, page 64).

• Check and/or replace gas valve. Gas valve energizes with 19-23 VDC. Recycle boiler by thermostat or service switch. Thermostat should call for heat and appropriate zone valves close.

• Wait 5 minutes.

Are FLAME & POWER lights ﬂashing?

No Ye s

• Call your local WilliamsonThermoﬂo sales representative.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting (continued)

CHART 5

Electrical shock hazard — Wherever you see TURN OFF POWER, follow the instructions. Failure to follow instructions could result in severe personal injury, death or substantial property damage.

• This is NOT a lockout mode.

• The IBC is signaling that the return water temperature sen-

sor is detecting a temperature less than 40 °F.

• While the temperature at the boiler return water temperature

• Attach sensor to pipe with clamp

provided.

• If problem persists, replace return water temperature sensor.

• Retest.

• Remove CIRCULATORS plug (Figure 90, page 78, Item 4)

from plug receptacle of IBC.

• Place voltmeter leads across the 120 VAC N

and 120 VAC H pins of the CIRCULATORS receptacle on the side corresponding to the circulator not operating.

Does the voltmeter indicate 120 VAC?

No Ye s

TSTAT/CIRC light ﬂashing and POWER light on steady

Is return water temperature sensor clamped securely to the return pipe in the boiler?

sensor is less than 40 °F, both of the internal boiler circulators will run continuously, even if there is no call for heat (though the boiler will not ﬁre until the thermostat calls for heat). This operation is intended to reduce chances of freezing during system down times by keeping water ﬂowing.

No Ye s

Are both boiler internal circulators operating?

No Ye s

Is there a call for heat?

• Verify by removing thermostat wirings at boiler and checking continuity across external wires.

• Replace the IBC (IBC).

• Retest.

• Replace circulator harness.

• Retest.

• Reconnect circulator harness to the IBC.

• Attempt to get the circulator started by giving it a sharp rap on the

end of the circulator motor (to release a possibly locked impeller).

• If the circulator begins to operate, allow it to operate for a few minutes to see if the problem clears.

• If problem persists, replace the bypass circulator.

• Retest.

• Test wire continuity of

circulator wire harness.

Is harness ok?

No Ye s

• This is normal operation for water less than 40 °F at boiler internal return pipe.

• Condition should change after a call for heat, when the boiler will heat up the water.

• Boiler is not heating.

• Troubleshoot boiler using

CHART 7, page 87.

• Boiler should now operate normally.

• Verify correct sequence of operation (Figure 71, page 64).

• Wait 10 minutes to allow

heat from the boiler to raise the water temperature.

Does LIMIT light quit ﬂashing (and pipes begin to heat up)?

No Ye s

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting (continued)

CHART 6

Electrical shock hazard — Wherever you see TURN OFF POWER, follow the instructions. Failure to follow instructions could result in severe personal injury, death or substantial property damage.

• This is NOT a lockout mode. The IBC should only be signaling that the water temperature sensor is either shorted or there is an open circuit across the sensor terminals.

• Remove SENSOR plug from receptacle on IBC (Figure 90, page 78, Item 6).

• Then re-insert.

LIMIT light ﬂashing and POWER light on steady

Does LIMIT light still ﬂash?

No Ye s

• This situation is usually corrected by replacing the sensor, as described below.

• Replace return or supply sensor and harness.

Does LIMIT light still ﬂash?

No Ye s

• Boiler may now be operating correctly. Verify per normal sequence of operation (Figure 71, page 64).

• Replace IBC.

• Retest.

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Troubleshooting (continued)

CHART 7

• Has it been at least 5 minutes since setting thermostat to call for heat? If not, wait 5 minutes. Is system heating?

• Is thermostat set to call for heat? Remove thermostat wires at boiler and check continuity across the two wires. If circuit isn't closed, check external thermostat (zone valve, relay, etc.) wiring. Correct problems and retry.

• Reconnect external thermostat wiring at boiler.

Is thermostat circuit closed (continuity across wires)?

No Ye s

Are all red lights off?

No Yes

• Wait 30 seconds.

Are all red lights

off?

No Ye s

• Replace IBC.

• Retest.

• Wait for cast iron

block to cool to room temperature.

Are block switch

contacts closed?

No Yes

• Replace switch.

• Retest.

• Replace

• Retest.

Insufﬁcient heat or no heat to system (POWER light on steady)

Electrical shock hazard — Wherever you see TURN OFF POWER, follow the instructions. Failure to follow instructions could result in severe personal injury, death or substantial property damage.

• Boiler is in standby.

• Set thermostat to call for heat

and recheck operation.

• Verify sequence of operation, Figure 71, page 64.

• Check block switch on top of boiler with continuity checker.

Are contacts closed?

No Yes

• Check across limit switch contacts with continuity checker.

Are contacts closed?

Ye s No

• Check across thermal fuse leads with continuity checker.

Is circuit closed?

No Yes

thermal fuse.

• Replace IBC.

• Retest.

Is boiler System circulator operating?

No Ye s

• Remove system circulator harness plug from CIR- CULATORS plug receptacle (long harness) (see

Figure 90, page 78, Item 4). Check with voltmeter across left-side 120 VAC N and 120 VAC H pins of receptacle.

Does voltmeter show 120 VAC across pins?

No Ye s

• Replace IBC.

• Retest.

• Wait 5 minutes.

Is FLAME light on?

No Ye s

• If you have sufﬁcient heat — boiler should follow normal operating sequence (Figure 71, page 64).

• If you have less than sufﬁcient heat —

Is vent or combustion air piping free of blockage?

No Ye s

• Correct conditions and recheck operation. See sequence of operation, Figure 71, page 64.

• Wait for boiler water to cool to temperature 20 to 30 °F lower than temperature set on the limit.

• Are limit switch contacts closed?

No Ye s

• Replace limit switch.

• Retest.

• Repair/replace circula-

tor. Retest.

• Repair/replace wiring. Retest.

• Contact your Williamson-Thermoﬂo sales representative.

• Excessive block temperature has been reduced to safe operating level. Check for low water level or mineral deposits in sections. Correct before proceeding.

• Restart boiler and check sequence of operation (Figure 71, page 64).

Part number 550-142-786/0712

• Boiler water temperature exceeded setting on limit switch with thermostat calling for heat. Boiler is OK. (See sequence of operation, Figure 71, page 64)

• Also check operation of setting limit (should be above 140°F.).

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Replacement parts

Figure 93 Miscellaneous parts

Description Model Williamson-

Thermoo

part number

Vent termination plate for 3" AL29-4C or 3" PVC pipes (plate includes knockouts to provide larger holes needed for PVC)

Vent Termination Bird Screen 3" PVC (1 pc) All 383-500-105WT

Termination bag assembly (includes two 2-hole sidewall termination plates and two bird screens, mounting screws and plastic anchors)

3" PVC Concentric Vent Kit All 383-500-350WT

Adapter 3-inch AL29-4C Vent Starter, FasNSeal All 560-907-717WT

Adapter 3-inch AL29-4C Vent Starter, Z-Vent All 560-907-723WT

Adapter 3-inch AL29-4C Vent Starter, Saf-T-Vent All 560-907-724WT

Adapter 3-inch AL29-4C Vent Starter, CORR/GUARD All

Chemicals:

Antifreeze, aluminum-safe, Sentinel X500 . . . . . . . . . . . . . . . . . . . . . . .

Corrosion inhibitor, Sentinel X100 . . . . . . . . . . . . . . . . . . . . . . . . . . .

(one tube is shipped with boiler)

Sentinel X100 Inhibitor Test Kit. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(one kit is shipped with boiler)

Cleaner, Sentinel X400. . . . . . . . . . . . . . . . . . . . . . . . . . . .

All 452-100-163WT

All 542-200-314WT

Contact Williamson-

Thermoﬂo

592-900-004WT 592-900-002WT

All

592-900-005WT

592-900-003WT

Condensate neutralizer kit All 383-500-631WT

Oil Lubricant 3 Oz Andersol 465 All 592-900-015WT

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Replacement parts (continued)

Figure 94 Section assembly

Item number

1 Block assembly, includes:

2 Front section replacement kit, includes front section, square

3 Intermediate section (also required Section replacement kit) All 312-200-110WT

4 Back section (also required Section replacement kit) All 312-200-130WT

Not

shown

Description Model Williamson-Thermoo

part number

070 Front section, intermediate section, back section, square cut seals — 2”, silicone sealant, tie rods, tie rod nuts, tie rod washers, blower ﬂange gasket, igniter, igniter gasket, screws, lock washers, studs, nuts

cut seals (4), silicone sealant, blower ﬂange gasket, igniter gasket, studs (13), nuts (13)

Section replacement kit All 382-200-305WT

105

140

175

All 382-200-713WT

322-200-304 322-200-305WT 322-200-306WT 322-200-307WT

5 Tie rods 070

105

140

175

6 Base rail legs — (2) per boiler 070 and 105

140 and 175

7 Base rail brace — (2) per boiler All 452-100-080WT

8 Blower housing support All 452-100-111WT

9 Block temperature limit switch All 382-200-375WT

10 Inspection port cover All In Insp. port kit

11 Inspection port gasket All 590-317-628

— Inspection port kit (includes cover and gasket) All 542-200-181WT

12 Recuperator connection gasket All 590-317-653WT

Stud, B\zn” – 18 x 1¼”

All 560-340-581WT

560-234-499WT 560-234-525WT 560-234-503WT 560-234-504WT

452-100-173WT 452-100-174WT

Part number 550-142-786/0712

Hex nuts (4 each), B\zn” / lock washers (4 each), B\zn”

All Obtain locally

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Replacement parts (continued)

Figure 95 Section assembly

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Replacement parts (continued)

Figure 96 Jacket assembly

Item number

1 Jacket panel, top 070 and 105

2 Jacket panel, front All 382-200-702WT

3 Jacket panel, left side, front 070

4 Jacket panel, left side, rear 070 and 105

5 Jacket panel, right side 070 and 105

6 Jacket panel, rear All 382-200-726WT

7 Jacket brace All 422-200-179WT

8 Jacket panel, interior All 382-200-727WT

Description Model Williamson-Thermoo

part number

382-200-735

140 and 175

105 140 175

140 and 175

382-200-736WT

382-200-730WT 382-200-731WT 382-200-732WT 382-200-733WT

382-200-705WT 382-200-706WT

382-200-724WT 382-200-725WT

9 Base rail assembly All see Figure 94, page 89

items 6 and 7

10 Screw, sheet metal type AB, serrated hex washer head

Phillips #10 x C\,” steel black phosphate

All —

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Replacement parts (continued)

Figure 97 Jacket assembly

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Replacement parts (continued)

Figure 98 Blower assembly

Item number

1 Burner replacement kit, includes burner, blower ﬂange gasket, igniter,

2 Blower ﬂange gasket All 590-317-610

3 Air pressure switch (0 to 5,500 feet elevation) All 382-200-723

— Air pressure switch (5,500 to 10,000 feet elevation) All 382-200-728WT

5 Blower housing assembly replacement kit, includes: blower housing,

6 Conversion kit, natural to propane, includes . . . . . . . . . . . . . . . . . . . . . .

12 Igniter replacement kit, includes igniter and gasket All 511-330-148

13 Igniter gasket All 590-317-599

14 Inlet air tube w/grill All 382-200-310

15 Hose clamp, 3” All 591-850-068

16 Inlet air hose, 3" by 19" long All 562-302-573

17 & 18 Inspection port cover and Inspection port gasket All

19 Recuperator connection gasket All 590-317-653WT

20 Condensate drain hose clamp All —

21 Condensate trap All 560-907-716

22 ½” PVC condensate tee All —

23 Condensate tee U-clamp All — 24 Recuperator kit, includes recuperator, recuperator connection gasket,

25 Diamond ﬂange, 1” npt All see item 24

26 Diamond ﬂange gasket All 590-317-535

27 Flue gas thermal fuse All 511-724-295

29 Flue drain hose kit, 6 inches All 382-200-717

30 Recuperator vent pipe seal All 593-000-006

Description Model Williamson-Thermoo

part number

igniter screws, igniter washers, igniter gasket

Blower motor replacement kit, includes blower motor, motor mounting grommets, screws, lock nuts and 9" Allen wrench

obsv. port, blower housing cover plate, blower motor mounting brackets, washer hold down bracket, lock nuts, motor mount grommets, blower motor, blower wheel, magnetic washer, silicone sealant, screws, blower ﬂange gasket, igniter, igniter washers, igniter screws, igniter gasket

Propane oriﬁce plate, label

Oriﬁce plate, natural gas . . . . . . . . . . . . . . . . . . . . . . 070

Gas/air manifold assembly, includes gas/air manifold, gas tubing, washers, screws, gas valve o-ring

Sense line condensate trap, includes sense line condensate trap and hoses

Gas valve kit, complete, includes

o-ring, screws

diamond ﬂange gasket (2), connection hardware (4-nuts), ﬂue gas thermal fuse

In-line ﬂue adapter with drain kit, includes in-line ﬂue adapter with drain and drain hose (6 inches)

gas valve, gas cock, 1/2" nipple, bracket,

070 105 140 175

All

All 381-356-587

070 105 140 175

105 140 175

All

070 and 105 140 and 175

All

382-200-320 382-200-325 382-200-330 382-200-335

381-356-584

510-811-926 510-811-927 510-811-928 510-811-929 510-811-934 510-811-935 510-811-936 510-811-937 382-200-362

382-200-409

382-200-411

see Figure 94, page 89

items 10 and 11

382-200-714 382-200-715

382-200-716

WT WT WT WT

WT WT WT WT WT WT WT WT WT

WT WT

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Replacement parts (continued)

Figure 99 Blower assembly

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Replacement parts (continued)

Figure 100 Trim assembly

Item number

1 System circulator, Taco 007 511-405-113WT

2 Bypass circulator, Taco 007 511-405-113WT

3 Circulator gasket, Taco 110-339 590-317-543WT

6 Square cut seal gaskets, casting, 2.31" 572-800-011WT

7 Diamond ﬂange gasket 590-317-535WT

Description Williamson-

Thermoo

part number

Manifold, casting/circulator kit, includes water manifold, circulator gasket (Taco 110-339) (2), square cut seal (manifold to casting)

Return manifold, recuperator/circulator kit, includes water manifold, circulator gasket (Taco 110-339) (1), diamond gasket

Supply manifold kit, includes water manifold, circulator gasket (Taco 110-339) (1), square cut seal (manifold to casting)

382-200-720WT

382-200-721WT

382-200-722WT

9 Coin-operated air vent, 1/8” NPT 570-148-565WT

10 Wiring harness, circulators to IBC 591-391-824WT

11 Return water temperature sensor and clip 511-330-089WT

12 Tee, 1” x 1” x ¾” Obtain locally

13 Bushing ¾” x ¼” Obtain locally

14 Temperature and Pressure Gauge, 1/4" NPT 510-218-099WT

15 30 PSIG Relief Valve 511-546-920WT

16 Nipple, NPT — ¾” x 3” Obtain locally

17 Block temperature limit switch 382-200-375WT

18 Boiler temperature sensor 381-356-577WT

19 Drain valve, ¾” NPT 511-546-392WT

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Replacement parts (continued)

Figure 101 Trim assembly

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Replacement parts (continued)

Figure 102 Interior panel

Item number

1 Interior panel see Figure 96, page 91,

2 Integrated boiler control assembly, includes IBC and screws 381-330-017WT

3 Transformer 381-356-578WT

4 Air pressure switch see Figure 98, page 93

Description Williamson-Thermoo

part number

item 8

item 3

not shown Wiring harness, IBC to hot surface ignitor 591-391-819WT

not shown Wiring harness, IBC to system and bypass circulators 591-391-824WT

not shown Wiring harness, IBC to junction box 591-391-984WT

not shown Wiring harness, IBC to controls 591-391-985WT

not shown Wiring harness, Thermostat 591-391-986WT

not shown Wiring harness, Sensor 591-391-995WT

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Replacement parts (continued)

Figure 103 Interior panel

Part number 550-142-786/0712

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Dimensions and ratings

Figure 104 Dimension drawing (see Figure 105, page 100 for dimensional table)

Item number

1 1” NPT Supply

2 1” NPT Return

3 Combination pressure-temperature gauge, 2 ½” short shank

4 ¾” NPT Relief valve outlet

5 Plug dome, 2” black

6 Junction box

7 Inlet air ﬁtting, 3" PVC

8 Flue outlet, 3" PVC

9 ½” Condensate drain

10 ½” NPT Gas supply connection (provided by others)

11 Drip leg (provided by others)

12 Union (provided by others)

13 Manual main shutoff gas valve (provided by others)

14 ON/OFF switch

Part number 550-142-786/0712

Description

GWC SerieS 2 gaS-fired water boiler — Boiler Manual

Dimensions and ratings (continued)

Figure 105 Boiler dimensional and physical data (see Figure 104, page 99)

Boiler

model

Supply

Return

Length

Gas connection size

(Note 1)

Electrical

service

required

(includes the internal circulators)

Boiler

water

content

Approx.

shipping

weight

(inches NPT

male)

GWC-070

GWC-105

GWC-140

GWC-175

Note 1: Gas piping from meter to boiler to be sized per local utility requirements.

1 1 30¾ ½ 15 3.8 313

1 1 30¾ ½ 15 4.7 353

1 1 37¾ ½ 15 6.0 423

1 1 37¾ ½ 15 6.9 464

(inches NPT

female)

(inches) (inches NPT

female)

Figure 106 Boiler ratings

Boiler model

CSA

Input

MBH MBH MBH % Inches Gallons Natural gas Propane Natural gas Propane

DOE

Heating

capacity

(Note 1)

Net AHRI

water rating

(Note 2)

AFUE

(Note 1)

Vent/

combustion

air diameter

Boiler water

content

(amperes) (gallons) (pounds)

DOE

% Input derate vs vent length

(Values shown are at maximum vent/air pipe length)

(Note 3)

Direct Exhaust Venting Direct Vent Venting

GWC-070

GWC-105

GWC-140

GWC-175

Notes:

70 65 56 91.9

105 97 84 91.2

140 130 113 91.4

175 161 140 91.0

1. Based on standard test procedures prescribed by the United States Department of Energy. Ratings also referred to as CSA Output. NOTE that only DOE Heating Capacity and AFUE are certiﬁed by AHRI. AFUE is also know as Annual Fuel Utilization Efﬁciency or Seasonal Efﬁciency.

2. Net AHRI ratings are based on net installed radiation of sufﬁcient quantity for the requirements of the building and nothing need be added for normal piping and pickup. Ratings are based on a piping and pickup allowance of 1.15 and are determined under the provisions governing forced draft boiler-burner units. An additional allowance should be made for unusual piping and pickup loads.

3. All of the boilers will automatically de-rate as vent length increases, due to the pressure loss through the vent. For vent/air pipe lengths less than the maximum, the derate equals the value above times vent length ÷ 100.

4. Boilers are tested for 50 PSIG working pressure.

5. GWC boilers are not available for millivolt systems.

100

3" PVC 3.8

3" PVC 4.7

3" PVC 6.0

3" PVC 6.9

up to 0.7% up to 1.4% up to 1.5% up to 2.8%

up to 1.0% up to 2.2% up to 4.0% up to 5.4%

up to 4.0% up to 4.0% up to 7.0% up to 8.0%

up to 4.0% up to 4.5% up to 7.0% up to 10.0%

Part number 550-142-786/0712

Williamson-Thermoflo GWC-070, GWC-105, GWC-140, GWC-175 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual