Lochinvar 2,065,000Btu User Manual

INSTALLATION AND SERVICE MANUAL

Save this manual for future reference.



WARNING: If the
information in this manual
is not followed exactly, a
fire or explosion may
result causing property
damage, personal injury or
loss of life.

– Do not store or use
gasoline or other
flammable vapors and
liquids in the vicinity of
this or any other appliance.

WHAT TO DO IF YOU SMELL
GAS

• Do not try to light any
appliance.

• Do not touch any
electric switch; do not
use any phone in your
building.

• Immediately call your
gas supplier from a
neighbors phone.
Follow the gas
supplier’s instructions.

• If you cannot reach your
gas supplier, call the fire
department.

– Installation and service
must be performed by a
qualified installer, service
agency or the gas supplier.



WARNING: Do not use
this appliance if any part
has been under water. The
possible damage to a
flooded appliance can be
extensive and present
numerous safety hazards.
Any appliance that has
been under water must be
replaced.



WARNING: Improper
installation, adjustment,
alteration, service or
maintenance can cause
property damage, personal
injury, exposure to
hazardous materials or
loss of life. Refer to this
manual. Installation and
service must be performed
by a qualified installer,
service agency or the gas
supplier. This unit contains
materials that have been
identified as carcinogenic,
or possibly carcinogenic,
to humans.

HYDRONIC HEATING BOILERS and

DOMESTIC WATER HEATERS

495,000 - 2,065,000 Btu/hr MODELS

CB-CW(E)-i&s-06

Hydronic Heating Boilers and
Domestic Water Heaters

2

Table of Contents

General Product Information . . . . . . . . . . . . . . . . . . . . . . . . .3

Special Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Product Identification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Locating Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Clearances from Combustible Construction . . . . . . . . . .6

Base for Combustible Floors . . . . . . . . . . . . . . . . . . . . .6

Freeze Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Pump Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Hydronic System Antifreeze . . . . . . . . . . . . . . . . . . . . . .7

Outdoor Boiler Installation . . . . . . . . . . . . . . . . . . . . . . .7

Shutdown and Draining . . . . . . . . . . . . . . . . . . . . . . . . .7

Freeze Protection for a Heating Boiler System . . . . . . . . . . .8

Combustion and Ventilation Air . . . . . . . . . . . . . . . . . . .8

Combustion Air Filter . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Combustion Air Options . . . . . . . . . . . . . . . . . . . . . . . . .9

Exhaust Fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Venting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

General Information . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Venting Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Vertical Vent Termination Clearances and Location . .10

Vent System Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Barometric Damper Location . . . . . . . . . . . . . . . . . . . .12

1. Conventional Negative Draft Venting . . . . . . . . . . .13

2. Outdoor Installation Venting . . . . . . . . . . . . . . . . . .14

Connecting to Gas Supply . . . . . . . . . . . . . . . . . . . . . . . . . .16

Gas Pressure Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Gas Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16

Connecting Gas Piping to Unit . . . . . . . . . . . . . . . . . . .17

Gas Train and Controls . . . . . . . . . . . . . . . . . . . . . . . . .17

Combination Gas Valves . . . . . . . . . . . . . . . . . . . . . . .18

Venting of Combination Gas Valves . . . . . . . . . . . . . .18

Checking Gas Supply Pressure . . . . . . . . . . . . . . . . . . .18

Gas Manifold Pressure Adjustment . . . . . . . . . . . . . . .19

Connecting to Water Supply . . . . . . . . . . . . . . . . . . . . . . . . .20

Inlet and Outlet Connections . . . . . . . . . . . . . . . . . . . .20

Relief Valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

Water Flow Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

Low Water Cutoff . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21

Connecting to Electrical Supply . . . . . . . . . . . . . . . . . . . . . .21

Terminal Strip Connection Options . . . . . . . . . . . . . . .22

Boiler System Piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Primary/Secondary Boiler Piping . . . . . . . . . . . . . . . . .24

Low Temperature Return Water Systems . . . . . . . . . . .25

Radiant Floor and Snow Melt Heating Systems . . . . . .25

Table of Contents

Installation with a Chilled Water System . . . . . . . . . . .26

Boiler Flow Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Boiler Bypass Requirements . . . . . . . . . . . . . . . . . . . . .27

Temperature/Pressure Gauge . . . . . . . . . . . . . . . . . . . . .27

Filling the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Water Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

Lighting Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . .28

To Turn Off Gas To Appliance . . . . . . . . . . . . . . . . . . .29

Setting Temperature Control . . . . . . . . . . . . . . . . . . . . .29

Locating Temperature Control . . . . . . . . . . . . . . . . . . .29

Temperature Control Settings . . . . . . . . . . . . . . . . . . . .30

Outdoor Air Reset Option . . . . . . . . . . . . . . . . . . . . . . .31

Boiler Operating Temperature Control . . . . . . . . . . . . .31

Temperature Control Sensors . . . . . . . . . . . . . . . . . . . .32

Placement of Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32

Remote Mounting of Sensor . . . . . . . . . . . . . . . . . . . . .33

Hot Surface Ignition System . . . . . . . . . . . . . . . . . . . . . . . . .33

Operation and Diagnostic Lights . . . . . . . . . . . . . . . . . . . . .35

Domestic Water Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . .36

Water Velocity Control . . . . . . . . . . . . . . . . . . . . . . . . .36

Water Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Pipe Size Requirements . . . . . . . . . . . . . . . . . . . . . . . .37

Circulating Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37

Minimum Pump Performance . . . . . . . . . . . . . . . . . . . .38

Heat Exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

Potable Hot Water Temperature Control Settings . . . . .38

Location of Cold Water Supply Piping Connections . .39

High Water Temperature Limit Control . . . . . . . . . . . .39

Optional Relief Valve . . . . . . . . . . . . . . . . . . . . . . . . . .39

Thermal Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Cathodic Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . .39

Cleaning and Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . .40

Flue Gas Passageways Cleaning Procedures . . . . . . . . . . . .40

Burner Removal and Cleaning . . . . . . . . . . . . . . . . . . .40

Heat Exchanger Cleaning . . . . . . . . . . . . . . . . . . . . . . .41

Electrical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Combustion and Ventilation Air . . . . . . . . . . . . . . . . . .41

Adjusting Differential Air Pressure . . . . . . . . . . . . . . . .41

Servicing Hot Surface Igniter and Ignition Module . . .43

Ignition System Checkout . . . . . . . . . . . . . . . . . . . . . . .44

Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45

Schematic/Wiring Diagrams . . . . . . . . . . . . . . . . . . . . . . . . .47

Revision Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . .Back Cover

GENERAL PRODUCT
INFORMATION

Special Instructions

This manual supplies information for the installation, operation
and servicing of the appliance. Read and understand this manual
completely before installing unit.

Installation and service must be performed by a qualified service
installer, service agency, or the gas supplier.

Unpacking

Upon receiving equipment, check for signs of shipping damage.
Pay particular attention to parts accompanying the boiler which
may show signs of being hit or otherwise being mishandled.
Verify total number of pieces shown on packing slip with those
actually received. In case there is damage or a shortage,
immediately notify the carrier.

Codes

The equipment shall be installed in accordance with those
installation regulations in force in the local area where the
installation is to be made. These shall be carefully followed in all
cases. Authorities having jurisdiction shall be consulted before
installations are made. In the absence of such requirements, the
installation shall conform to the latest edition of the National Fuel
Gas Code, ANSI Z223.1 and/or CAN/CGA-B149 Installation
Code. Where required by the authority having jurisdiction, the
installation must conform to American Society of Mechanical
Engineers Safety Code for Controls and Safety Devices for
Automatically Fired Boilers, ASME CSD 1. All boilers conform
to the latest edition of the ASME Boiler and Pressure Vessel
Code, Section IV.

Warranty

Factory warranty (shipped with unit) does not apply to units
installed or operated improperly.

In most cases, improper installation or system design causes
most operating problems.

1. Excessive water hardness causing a lime build up in the
copper tube is not the fault of the equipment and is not
covered under the appliance manufacturer's warranty (see
Water Treatment, page 28 and Water Chemistry, page 37).

2. Excessive pitting and erosion on the inside of the copper

tube may be caused by too much water velocity through
the tubes and is not covered by the appliance
manufacturer's warranty (see System Temperature Rise
Chart on page 26 for flow requirements).

SAFETY INFORMATION

The information contained in this manual is intended for use
by qualified professional installers, service technicians or gas
suppliers. Consult your local expert for proper installation or
service procedures.

IMPORTANT: Read this owner's manual carefully
and completely before trying to install, operate, or
service this unit. Improper use of this unit can
cause serious injury or death from burns, fire,
explosion, electrical shock, and carbon monoxide
poisoning.

 DANGER: Carbon Monoxide poisoning may

lead to death!

IMPORTANT: Consult and follow local building and
fire regulations and other safety codes that apply
to this installation. Consult your local gas utility
company to authorize and inspect all gas and flue
connections.

 WARNING: Should overheating occur or the

gas supply fail to shut off, do not turn off or
disconnect the electrical supply to the pump.
Instead, shut off the gas supply at a location
external to the unit.

 WARNING: To minimize the possibility of

serious personal injury, fire or damage to your unit,
never violate the following safety rules.

1. This unit is only for use with the type of gas indicated on the
rating plate.

2. If you smell gas

• shut off gas supply

• do not try to light any appliance

• do not touch any electrical switch; do not use any

phone in your building

• immediately call your gas supplier from a neighbor's

phone. Follow the gas supplier's instructions

• if you cannot reach your gas supplier, call the fire

department

Installation and

Service Manual

3

3. Boilers and water heaters are heat producing appliances. To
avoid damage or injury, do not store materials against the
appliance or the vent-air intake system. Use proper care to
avoid unnecessary contact (especially children) with the
appliance and vent-air intake components. Follow all
clearances from combustibles contained in this manual.

4. Never cover your unit, lean anything against it, store trash or
debris near it, stand on it or in any way block the flow of
fresh air to your appliance.

5. UNDER NO CIRCUMSTANCES must flammable materials
such as gasoline or paint thinner be used or stored in the
vicinity of this appliance, vent-air intake system or any
location from which fumes could reach the appliance or vent­air intake system.

6. Appliance surfaces become hot during operation. Be careful
not to touch hot surfaces. Keep all adults, children, and
animals away from an operating hot unit. Severe burns can
occur.

7. You must take adequate care to prevent scald injury when
storing water at elevated temperatures for domestic use.

8. This unit must have an adequate supply of fresh air during
operation for proper gas combustion and venting.

9. Make sure all exhaust venting is properly installed and
maintained. Improper venting of this unit could lead to
increased levels of carbon monoxide.

10. Do not use this boiler if any part has been under water.
Immediately call a qualified service technician to replace the
boiler. The possible damage to a flooded boiler can be
extensive and present numerous safety hazards. Any
appliance that has been under water must be replaced.

11. Do not alter this unit in any way. Any change to this unit or
its controls can be dangerous.

Hydronic Heating Boilers and
Domestic Water Heaters

4

Installation and

Service Manual

5

Figure 1 – Front and Rear View

Rear View

Front View

PRODUCT
IDENTIFICATION

INSTALLATION

This unit meets the safe lighting performance criteria with the
gas manifold and control assembly provided, as specified in
the ANSI standards for gas-fired units, ANSI Z21.13/CSA 4.9
and ANSI Z21.10.3/CSA 4.3.

LOCATING UNIT

1. Maintain all clearances from combustible construction when
locating unit. See Clearances from Combustible
Construction, this page.

2. Locate the unit so that if water connections should leak,
water damage will not occur. When such locations cannot
be avoided, install a suitable drain pan that is well-drained
under the unit. The pan must not restrict combustion air
flow. The appliance manufacturer is not responsible for
water damage in connection with this unit, or any of its
components.

3. Install indoor units so that the ignition system components
are protected from any water while operating or during
service.

4. Appliances located in a residential garage and in adjacent
spaces that open to the garage and are not part of the living
space of a dwelling unit must be installed so that all
burners and burner ignition devices have a minimum
clearance of not less than 18" (46cm) above the floor. The
appliance must be located or protected so that it is not
subject to physical damage by a moving vehicle.

5. DO NOT install this appliance in any location where
gasoline or flammable vapors are likely to be present.

6. You must install unit on a level, non-combustible floor.

7. Do not install unit directly on carpet or other combustible
material. A concrete-over-wood floor is not considered
non-combustible. Maintain required clearances from
combustible surfaces.

If installing unit in an area with a combustible floor, you
must use a special combustible floor base. See Base for
Combustible Floors, this page.

8. For outdoor models, you must install an optional vent kit.
Instructions for mounting the vent kit are included in the
venting section. Do not install outdoor models directly on
the ground. You must install the outdoor unit on a concrete,
brick, block, or other non-combustible pad. Outdoor
models have additional special location and clearance
requirements. See Outdoor Installation Venting, page 14.
A wind proof cabinet protects the unit from weather.

Clearances from Combustible
Construction

Maintain minimum specified clearances for adequate
operation. Allow sufficient space for servicing pipe
connections, pump and other auxiliary equipment, as well as
the unit. See rating plate for specific service clearance
requirements.

Right Side 3" (7.5 cm)

Rear 3" (7.5 cm) (3" min. from any surface)

Left Side 6" (15cm) (24" (0.61m) suggested for

service)

Front Alcove* (30" (0.76m) suggested for

service)

To p 3" (7.5cm)

Flue 1" (25.4mm)

Hot Water Pipes 1" (25.4mm)

*An Alcove is a closet without a door.

Note: No additional clearance is needed on the right side of the
unit for the observation port. An observation port is located on
both the right and left side of the unit.

Figure 2 - Clearances from Combustible Construction

Base for Combustible Floors

There is no manufactured combustible floor base kit available
for 985,000 - 2,065,000 Btu/hr models. You must construct a

Hydronic Heating Boilers and
Domestic Water Heaters

6

base for combustible floor installation. Install unit over a base
of hollow clay tiles or concrete blocks from 8" to 12" thick and
extending at least 24" beyond the unit sides. Place tiles or
blocks so that the holes line up horizontally to provide a clear
passage through the tiles or blocks. Place a 1/2" fireproof
millboard over the top of the tile or block base. Place a 20­gauge sheet metal cover over the fireproof millboard. Center
the unit on the base. Also follow this procedure if electrical
conduit runs through the floor beneath the unit. This base must
meet all local fire and safety codes.

FREEZE PROTECTION

Although these units are CSA International design certified for
outdoor installations, such installations are not recommended
in areas where the danger of freezing exists. You must provide
proper freeze protection for outdoor installations, units
installed in unheated mechanical rooms or where temperatures
may drop to the freezing point or lower. If freeze protection is
not provided for the system, a low ambient temperature alarm
is recommended for the mechanical room. Damage to the unit
by freezing is non-warrantable.

Anytime the temperature measured at any of the sensors
(except the outside air temperature sensor) drops below 40°F,
the control turns on the pump contact and the alarm relay. The
pump will shut off when both sensors are above 50°F.

Pump Operation

This unit is equipped with a pump delay of 30 seconds. If
continuous operation of the pump is desired, the pump must be
electrically connected to another circuit. Connection of the
pump to this unit will provide intermittent pump delay
operation.

Location

Locate indoor boilers and hot water supply boilers in a room
having a temperature safely above freezing [32°F (0°C)].

 CAUTION: A mechanical room operating

under a negative pressure may experience a
down draft in the flue of a boiler which is not
firing. The cold outside air pulled down the flue
may freeze a heat exchanger. This condition
must be corrected to provide adequate freeze
protection.

Hydronic System Antifreeze

Freeze protection for a heating boiler or hot water supply
boiler using an indirect coil can be provided by using hydronic
system antifreeze. Follow the appliance manufacturers
instructions. Do not use undiluted or automotive type
antifreeze.

Outdoor Boiler Installation

Adequate hydronic system antifreeze must be used. A snow
screen should be installed to prevent snow and ice
accumulation around the unit or its venting system.

Shut-Down and Draining

If for any reason, the unit is to be shut off, the following
precautionary measures must be taken:

1. Shut off gas supply.

2. Shut off water supply.

3. Shut off electrical supply

4. Drain the unit completely. Remove one threaded plug or
bulbwell from the inlet side of the front header and one
from the outlet side of the front header on the heat
exchanger. Blow all water out of the heat exchanger (see
Figure 3).

5. Drain pump and piping.

Figure 3 - Draining Unit

Installation and

Service Manual

7

495,000 CFK3302
645,000 CFK3303
745,000 CFK3304

TABLE - A

COMBUSTIBLE FLOOR KITS

Input Btu/hr Kit Number

INSTALLATION

Continued

Freeze Protection for a Heating
Boiler System (if required)

1. Use only properly diluted inhibited glycol antifreeze
designed for hydronic systems. Inhibited propylene glycol
is recommended for systems where incidental contact with
drinking water is possible.

 WARNING: Do not use undiluted or

automotive type antifreeze.

2. A solution of 50% antifreeze will provide maximum
protection of approximately -30°F.

3. Follow the instructions from the antifreeze manufacturer.
Quantity of antifreeze required is based on total system
volume including expansion tank volume.

4. Glycol is denser than water and changes the viscosity of
the system. The addition of glycol will decrease heat
transfer and increase frictional loss in the boiler and related
piping. A larger pump with more capacity (15% to 25%
more) may be required to maintain desired flow rates and
prevent a noise problem in a glycol system.

5. Local codes may require a back flow preventer or actual
disconnect from city water supply when antifreeze is
added to the system.

COMBUSTION AND VENTILATION
AIR

Provisions for combustion and ventilation air must be in
accordance with Section 5.3, Air for Combustion and
Ventilation, of the latest edition of the National Fuel Gas Code,
ANSI Z223.1, in Canada, the latest edition of CAN/CGA­B149 Installation Code for Gas Burning Appliances and
Equipment, or applicable provisions of the local building
codes.

Provide properly-sized openings to the equipment room to
assure adequate combustion air and proper ventilation when
the unit is installed with conventional venting or sidewall
venting.

Combustion Air Filter

The 985,000 - 2,065,00 Btu/hr models have a standard air
filter(s) located behind the combustion air inlet panel(s). This
filter helps ensure clean air is used for the combustion process.

Check this filter every month and replace when it becomes
dirty. The filter size is 12" x 16" x 1" (30.5cm x 40.6cm x

2.5cm) . You can find this commercially available filter at any
home center or HVAC supply store.

Installing Combustion Air Filter

To install the filter(s), remove the combustion air inlet panel(s).
The 985,000 - 1,435,000 Btu/hr models have one combustion air
inlet panel located on the left front of the unit (see Figure 4). The
1,795,000 and 2,065,000 Btu/hr models have two combustion air
inlet panels located on the left and right front of the unit (see
Figure 5).

1. Loosen knurled knob at the bottom of the control panel
cover.

2. Pull the bottom of the panel(s) out and down to remove.

3. Place filter(s) in opening(s).

4. Replace combustion air inlet panel(s).

Figure 4 - Installing Combustion Air Filter, 985,000 ­1,435,000 Btu/hr Models

Figure 5 - Installing Combustion Air Filters, 1,795,000 and
2,065,000 Btu/hr Models

Hydronic Heating Boilers and
Domestic Water Heaters

8

Combustion Air Options

 CAUTION: Under no circumstances

should the mechanical room ever be under a
negative pressure. Particular care should be
taken where exhaust fans, attic fans, clothes
dryers, compressors, air handling units, etc.,
take away air from the unit.

1. Outside Combustion Air, No Ducts You can direct
outside combustion air to this unit using either one or two
permanent openings.

One Opening

The opening must have a minimum free area of one square
inch per 3000 Btu input (7cm

2

per kW). You must locate this

opening within 12" (30cm) of the top of the enclosure.

Figure 6 - Outside Combustion Air - Single Opening

Two Openings

The combustion air opening must have a minimum free area of
one square inch per 4000 Btu input (5.5cm

2

per kW). You must
locate this opening within 12" (30cm) of the bottom of the
enclosure.

The ventilation air opening must have a minimum free area of
one square inch per 4000 Btu input (5.5cm

2

per kW). You must
locate this opening within 12" (30cm) of the top of the
enclosure.

Figure 7 - Outside Combustion Air - Two Openings

2. Outside Combustion Air, Using Ducts

You can direct outside combustion air to this unit using two air
ducts to deliver the air to the boiler room.

Each of the two openings must have a minimum free area of
one square inch per 2000 Btu input (11cm

2

per kW).

Figure 8 - Outside Combustion Air Through Ducts

3. Combustion Air from Interior Space

You can direct combustion air to this unit using air from an
adjoining interior space. You must provide two openings from
the boiler room to the adjoining room.

Each of the two openings must have a net free area of one
square inch per 1000 Btu input (22cm

2

per kW), but not less

than 100 square inches (645cm2).

Installation and

Service Manual

9

INSTALLATION

Continued

Figure 9 - Combustion Air from Interior Space

All dimensions are based on net free area in square inches.
Metal louvers or screens reduce the free area of a combustion
air opening a minimum of approximately 25%. Check with
louver manufacturers for exact net free area of louvers. Where
two openings are provided, one must be within 12" (30 cm) of
the ceiling and one must be within 12" (30 cm) of the floor of
the mechanical room. Each opening must have a minimum net
free area as specified in TABLE-C, page 12. Single openings
shall be installed within 12" (30 cm) of the ceiling.

The combustion air supply must be completely free of any
flammable vapors that may ignite or chemical fumes which
may be corrosive to the appliance. Common corrosive
chemical fumes which must be avoided are fluorocarbons and
other halogenated compounds, most commonly present as
refrigerants or solvents, such as Freon, trichlorethylene,
perchlorethylene, chlorine, etc. These chemicals, when
burned, form acids which quickly attack the heat exchanger
finned tubes, headers, flue collectors, and the vent system. The
result is improper combustion and a non-warrantable,
premature appliance failure.

Exhaust Fans

Any fan or equipment which exhausts air from the boiler room
may deplete the combustion air supply and/or cause a down
draft in the venting system. Spillage of flue products from the
venting system into an occupied living space can cause a very
hazardous condition that must be corrected immediately. If a
fan is used to supply combustion air to the boiler room, the
installer must make sure that it does not cause drafts which
could lead to nuisance operational problems with the boiler.

VENTING

General Information

You must supply adequate combustion and ventilation air to
this unit. You must provide minimum clearances for the vent
terminal from adjacent buildings, windows that open, and
building openings. Follow all requirements set forth in the
latest edition of the National Fuel Gas Code, ANSI Z223.1, in
Canada, the latest edition of CAN/CGA Standard B149
Installation Code for Gas Burning Appliances and Equipment
or applicable local building codes. Vent installations for
connection to gas vents or chimneys must be in accordance
with Part 7, "Venting of Equipment" of the above-mentioned
standards.

IMPORTANT: Examine the venting system at
least once each year. Check all joints and vent
pipe connections for tightness. Also check for
corrosion or deterioration. If you find any
problems, correct them at once.

Venting Support

Support horizontal portions of the venting system to prevent
sagging. Provide an upward slope of at least 1/4 inch per foot
(21mm/m) on all horizontal runs from the unit to the vertical
flue run or to the vent terminal on sidewall venting
installations.

Do not use an existing chimney as a raceway if another
appliance or fireplace is vented through the chimney. The
weight of the venting system must not rest on the unit. Provide
adequate support of the venting system. Follow all local and
applicable codes. Secure and seal all vent connections. Follow
the installation instructions from the vent material
manufacturer.

Vertical Vent Termination Clearances
and Location

The vent terminal should be vertical and exhaust outside the
building at least 2 feet (0.61m) above the highest point of the
roof within a 10 foot (3.05m) radius of the termination.

The vertical termination must be a minimum of 3 feet (0.91m)
above the point of exit.

A vertical termination less than 10 feet (3.05m) from a parapet
wall must be a minimum of 2 feet (0.61m) higher than the
parapet wall.

Hydronic Heating Boilers and
Domestic Water Heaters

10

You must locate the air inlet termination elbow at least 12"
(30cm) above the roof or above normal snow levels.

Keep the vent cap clear of snow, ice, leaves, and debris to
avoid blocking the flue.

Figure 10 - Vent Termination from Peaked Roof - 10' or
Less From Ridge

IMPORTANT: Vent terminations are not shown in
Figures 10, 11, 12, and 13. Make sure all vertical
vents are installed with vent terminations
recommended by the vent manufacturer.

Figure 11 - Vent Termination from Peaked Roof More Than
10' From Ridge

Figure 12 - Vent Termination from Flat Roof 10' or Less from
Parapet Wall

Figure 13 - Vent Termination from Flat Roof More Than 10'
from Parapet Wall

 CAUTION: Units which are shut down or

will not operate may experience freezing due to
convective air flow in the flue pipe, through the
air inlet, or from negative pressure in the
mechanical room. In cold climates, operate pump
continuously to help prevent freezing of boiler
water. Provide proper freeze protection. See
Freeze Protection, page 7.

TABLE-A

Flue Pipe Sizes

Installation and

Service Manual

11

INSTALLATION

Continued

Input Flue

Btu/hr Size

495,000 6"

645,000 8"

745,000 8"

985,000 10"

1,255,000 12"

1,435,000 12"

1,795,000 14"

2,065,000 14"

Vent System Options

This unit has two venting options.

1. Conventional Negative Draft Venting

This option uses a vertical rooftop flue termination.
Combustion air is supplied from the mechanical room. See
page 13 for detailed information.

2. Outdoor Installation Venting

This option uses the installation of special air inlet and vent
caps on the unit. See page 13 for venting details.

All units are shipped from the factory equipped for
conventional negative draft venting. All other optional vent
systems require the installation of specific vent kits and
venting materials. The following is a detailed explanation of
the installation requirements for each venting system,
components used and part numbers of vent kits for each model.

Barometric Damper Location

Any venting system option that requires a barometric damper
must adhere to the following directions for optimum
performance.

The preferred location for the barometric damper is in a tee or
collar installed in the vertical pipe rising from the unit’s flue
outlet. The barometric damper MUST NOT be installed in a
bull head tee installed on the unit’s flue outlet. The tee or collar
containing the barometric damper should be approximately
three feet vertically above the connection to the unit’s flue
outlet. This location ensures that any positive velocity pressure
from the unit’s internal combustion fan is dissipated and the
flue products are rising due to buoyancy generated from the
temperature of the flue products. Adjust weights on damper to
ensure that draft is maintained within the specified ranges.

Hydronic Heating Boilers and
Domestic Water Heaters

12

TABLE - B

Flue Pipe Sizes

TABLE–C

Minimum Recommended Combustion Air Supply To Boiler Room

Combustion Air Source

Boiler Input Outside Air*/2 Openings Outside Air*/1 Opening Inside Air/2 Openings

495,000 125 in2(806 cm2) 167 in2(1077 cm2) 500 in2(3226 cm2)

645,000 163 in

2

(1052 cm2) 217 in2(1400 cm2) 650 in2(4194 cm2)

745,000 188 in

2

(1213 cm2) 250 in2(1613 cm2) 750 in2(4839 cm2)

985,000 248 in

2

(1,600cm2) 330 in2(2,129cm2) 990 in2(6,388cm2)

1,255,000 315 in

2

(2,032cm2) 420 in2(2,710cm2) 1260 in2(8,130cm2)

1,435,000 360 in2(2,323cm2) 480 in2(3,097cm2) 1440 in2(9,291cm2)

1,795,000 450 in2(2,903cm2) 600 in2(3,871cm2) 1800 in2(11,614cm2)

2,065,000 518 in2(3,342cm2) 690 in2(4,452cm2) 2070 in2(13,356cm2)

*Outside air openings shall directly communicate with the outdoors. When combustion air is drawn from the outside through a duct, the net free area of each of the two openings
must have twice (2 times) the free area required for Outside Air/2 Openings. The above requirements are for the boiler only, additional gas fired units in the boiler room will require
an increase in the net free area to supply adequate combustion air for all units. Combustion air requirements are based on the latest edition of the National Fuel Gas Code, ANSI
Z223.1, in Canada refer to CAN/CGA-B149 Installation Code. Check all local code requirements for combustion air.

1. Conventional Negative Draft
Venting

IMPORTANT: Before installing a venting system,
follow all venting clearances and requirements
found in the Venting, General Information
section, page 10.

Figure 14 - Conventional Negative Draft Vertical Venting
with Combustion Air Louvers

This option uses Type-B double-wall flue outlet piping. The
blower brings in combustion air. The buoyancy of the heated
flue products cause them to rise up through the flue pipe. The
flue outlet terminates at the rooftop.

Negative Draft

The negative draft in a conventional vent installation must be
within the range of 0.02 to 0.08 inches w.c. to ensure proper
operation. Make all draft readings while the unit is in stable
operation (approximately 2 to 5 minutes).

Connect the flue vent directly to the flue outlet opening on the
top of the unit. No additional draft diverter or barometric
damper is needed on single unit installations with a dedicated
stack and a negative draft within the specified range of 0.02 to

0.08 inches w.c. If the draft in a dedicated stack for a single
unit installation exceeds the maximum specified draft, you
must install a barometric damper to control draft. Multiple unit
installations with combined venting or common venting with
other Category I negative draft appliances require each boiler
to have a barometric damper installed to regulate draft within
the proper range.

Do not connect vent connectors serving appliances vented by
natural draft (negative draft) to any portion of a mechanical
draft system operating under positive pressure. Connecting to
a positive pressure stack may cause flue products to be
discharged into the living space causing serious health injury.

Flue Outlet Piping

With this venting option, you must use Type-B double-wall (or
equivalent) vent materials. Vent materials must be listed by a
nationally-recognized test agency for use as vent materials.
Make the connections from the unit vent to the outside stack as
direct as possible with no reduction in diameter. Use the
National Fuel Gas Code venting tables for double-wall vent to
properly size all vent connectors and stacks. Follow the vent
manufacturer's instructions when installing Type-B vents and
accessories, such as firestop spacers, vent connectors,
thimbles, caps, etc.

Provide adequate clearance to combustibles for the vent
connector and firestop.

When planning the venting system, avoid possible contact with
plumbing or electrical wiring inside walls, ceilings, and floors.
Locate the unit as close as possible to a chimney or gas vent.

Avoid long horizontal runs of the vent pipe, 90° elbows,
reductions and restrictions.

No additional draft diverter or barometric damper is required
on single unit installations with a dedicated stack and a
negative draft maintained between 0.02 to 0.08 inches w.c.

Common Venting Systems

You can combine the flue with the vent from any other
negative draft, Category I appliance. Using common venting
for multiple negative draft appliances requires you to install a
barometric damper with each unit. This will regulate draft
within the proper range. You must size the common vent and
connectors from multiple units per the venting tables for Type­B double-wall vents in the latest edition of the National Fuel
Gas Code, ANSI Z223.1 and/or CAN/CGA-B149 Installation
Code.

Common venting systems may be too large when an existing
unit is removed.

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

1. Seal any unused opening in the common venting system.

2. Visually inspect the venting system for proper size and
horizontal pitch. Make sure there is no blockage or
restriction, leakage, corrosion and other unsafe conditions.

3. If possible, close all building doors and windows. Close all
doors between the space in which the appliances remaining
connected to the common venting system are located and
other building spaces.

Installation and

Service Manual

13

INSTALLATION

Continued

4. Turn on clothes dryers and any other appliances 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.

5. Close fire place dampers.

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

7. Test for spillage at the 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.

8. After making sure that each appliance remaining
connected to the common venting system properly vents
when tested as above, return doors, windows, exhaust fans,
fireplace dampers and other gas burning appliances to their
previous conditions of use.

9. Correct any improper operation of the common venting
system so that the installation conforms to the latest edition
of the National Fuel Gas Code, ANSI Z223.1, in Canada,
the latest edition of CAN/CGA-B149 Installation Code for
Gas Burning Appliances and Equipment. When resizing
any portion of the common venting system, resize to
approach the minimum size as determined using the
appropriate tables of the latest edition of the National Fuel
Gas Code, ANSI Z223.1, in Canada, the latest edition of
CAN/CGA-B149 Installation Code for Gas Burning
Appliances and Equipment.

Masonry Chimney Installations

A masonry chimney must be properly sized for the installation
of a high efficiency gas-fired appliance. Venting of a high
efficiency appliance into a cold or oversized masonry chimney
can result in operational and safety problems. Exterior
masonry chimneys, with one or more sides exposed to cold
outdoor temperatures, are more likely to have venting
problems. The temperature of the flue products from a high
efficiency appliance may not be able to sufficiently heat the
masonry structure of the chimney to generate proper draft. This
will result in condensing of flue products, damage to the
masonry flue/tile, insufficient draft and possible spillage of
flue products into an occupied living space. Carefully inspect
all chimney systems before installation.

Inspection of a Masonry Chimney

A masonry chimney must be carefully inspected to determine
its suitability for the venting of flue products. A clay-tile-lined
chimney must be structurally sound, straight and free of
misaligned tile, gaps between liner sections, missing sections
of liner or any signs of condensate drainage at the breeching or
clean out. If there is any doubt about the condition of a
masonry chimney, it must be relined with a properly-sized and
approved chimney liner system. An unlined masonry chimney
must not be used to vent flue products from this high­efficiency unit. An unlined chimney must be relined with an

approved chimney liner system when a new appliance is
being attached to it. Metallic liner systems (Type-B double-

wall or flexible or rigid metallic liners) are recommended.
Consult with local code officials to determine code
requirements or the advisability of using or relining a masonry
chimney.

Vertical Vent Termination Clearances
and Location

Follow all vertical venting termination information for
clearances and location under Vertical Vent Termination
Clearances and Location, page 10.

2. Outdoor Installation Venting

IMPORTANT: Before installing a venting system,
follow all venting clearances and requirements
found in the Venting, General Information section,
page 10.

Units are self-venting and can be used outdoors when installed
with the optional outdoor caps. These caps mount directly to the
unit and cover the flue outlet and combustion air inlet openings.
No additional vent piping is required.

 WARNING: Only install outdoor models

outdoors and only use the vent caps supplied by
the appliance manufacturer. Personal injury or
product damage may result if any other cap is
used or if an outdoor model is used indoors.
Properly install all covers, doors and jacket panels
to ensure proper operation and prevent a
hazardous condition.

Combustion air supply must be free of contaminants (see
Combustion and Ventilation Air, page 8). To prevent recirculation
of the flue products into the combustion air inlet, follow all
instructions in this section.

Hydronic Heating Boilers and
Domestic Water Heaters

14

Outdoor Vent/Air Inlet Location

Keep venting areas free of obstructions. Keep area clean and free
of combustible and flammable materials. Maintain a minimum
clearance of 3" (76mm) to combustible surfaces and a minimum
of 3" (76mm) clearance to the air inlet. To avoid a blocked air
inlet or blocked flue condition, keep the air inlet, flue outlet and
drain slot clear of snow, ice, leaves, debris, etc.

Do not install outdoor models directly on the ground. You must
install the outdoor unit on a concrete, brick, block, or other
non-combustible pad.

Do not locate unit so that high winds can deflect off of adjacent
walls, buildings or shrubbery causing recirculation.
Recirculation of flue products may cause operational
problems, bad combustion or damage to controls. Locate unit
at least 3 feet (0.91m) from any wall or vertical surface to
prevent wind conditions from affecting performance.

Multiple outdoor unit installations require 48" (1.22m)
clearance between each vent cap. Locate the outdoor cap at
least 48" (1.22m) below and 48" (1.22m) horizontally from
any window, door, walkway or gravity air intake.

Locate the unit at least 10 feet (3.05m) away from any forced
air inlet.

Locate the unit at least 3 feet (0.91m) outside any overhang.

Clearances around outdoor installations can change with time.
Do not allow the growth of trees, shrubs or other plants to
obstruct the proper operation of the outdoor vent system.

Do not install in locations where rain from building runoff
drains will spill onto the unit.

TABLE-C

Input Kit* Kit*

Btu/hr w/ Pump without

Cover Pump Cover

495,000 ODK3023 ODK3014

645,000 ODK3024 ODK3015

745,000 ODK3024 ODK3015

985,000 ODK3046 ODK3043

1,255,000 ODK3047 ODK3044

1,435,000 ODK3047 ODK3044

1,795,000 ODK3048 ODK3045

2,065,000 ODK3048 ODK3045

* These kits include an outdoor vent cap, air inlet hood(s), and gasket.

Flue gas condensate can freeze on exterior walls or on the vent
cap. Frozen condensate on the vent cap can result in a blocked
flue condition. Some discoloration to exterior building or unit
surfaces can be expected. Adjacent brick or masonry surfaces
should be protected with a rust resistant sheet metal plate.

The Outdoor Vent Kit

The optional outdoor vent kit is available from the appliance
manufacturer. The outdoor kit part numbers are listed by unit
size. See TABLE-D for kit numbers.

You can install the outdoor vent cap and combustion air inlet
panel(s) on the unit (see Figures 15 and 16).

Figure 15 - Outdoor Vent Cap Installed on
495,000 - 1,435,000 Btu/hr Models

Figure 16 - Outdoor Vent Cap Installed on 1,795,000 and
2,065,000 Btu/hr Models

Installation and

Service Manual

15

TABLE - D

Outdoor Vent Kits

INSTALLATION

Continued

CONNECTING TO GAS
SUPPLY

Only supply the gas type specified on the unit's rating plate.
This unit is orificed for operation up to 2000 feet altitude. If
installing above 2000 feet elevation, consult the appliance
manufacturer.

INLET PRESSURE: Measure inlet pressure at the inlet
pressure tap located upstream of the combination gas valve(s).

See TABLE-E for maximum and minimum inlet pressures. Do
not exceed the maximum. Minimum inlet pressure is for the
purposes of input adjustment.

Input Max. Min.

495,000 - 745,000 Btu/hr

Nat. Gas 10.5" w.c. 4" w.c.

LP Gas 13" w.c. 8" w.c.

985,000 - 2,065,000 Btu/hr

Nat. Gas 10.5" w.c. 4.5" w.c.

LP Gas 13" w.c. 8" w.c.

MANIFOLD PRESSURE: Measure manifold pressure at the
pressure tap on the downstream side of the combination gas
valves. The gas regulator on the unit's combination gas valve
is adjustable to supply proper manifold pressure for normal
operation. See TABLE-I for net manifold pressure settings.

If you must adjust regulator pressure, follow the instructions
under Gas Manifold Pressure Adjustment, page 19. Do not
increase regulator pressure beyond the specified pressure
setting.

Gas Pressure Test

1. Disconnect the unit from the gas supply piping system
during any piping system pressure testing greater than 1/2
PSIG (3.5kPa).

2. Isolate the unit from the gas supply piping system by
closing a manual shutoff valve during any piping system
pressure testing that is equal to or less than 1/2 PSIG
(3.5kPa).

3. Test all gas connections for gas leaks before placing unit in
operation.

Gas Piping

To safely operate this unit, you must properly size the gas
supply piping. See TABLES- F, G, & H for piping and fitting
requirements. Gas pipe size may be larger than heater
connection.

The gas connection for models 495,000 to 745,000 Btu/hr is
1 1/4" NPT and on models 985,000 to 2,065,000 Btu/hr the
gas connection to these units is 2" NPT.

For ease of service, install a union.

Install a manual main gas shutoff valve, outside of the unit gas
connection within six feet of the unit in accordance with the
requirements of the National Fuel Gas Code, ANSI Z223.1.

You must provide a sediment trap (drip leg) in the inlet of the
gas connection to the unit.

Figure 17 - 495,000 - 745,000 Btu/hr Gas Line Connection
Example

Figure 18 - 985,000 - 2,065,000 Btu/hr Gas Line Connection
Example

IMPORTANT: Do not block access to the
electrical cover plate when installing the
sediment trap. The sediment trap must be a
minimum of 12 inches from the appliance.

Hydronic Heating Boilers and
Domestic Water Heaters

16

TABLE - E

Inlet Pressure

The combination gas valves have an integral vent limiting
device and does not require venting to atmosphere outside the
building. The unit will not operate properly if the reference
hose is removed or a vent to atmosphere is installed.

Optional gas controls may require routing of bleeds and vents
to the atmosphere outside the building when required by local
codes.

Connecting Gas Piping to Unit

All gas connections must be made with pipe joint compound
resistant to the action of liquefied petroleum (L.P.) and natural
gases. All piping must comply with local codes and
ordinances. Piping installations must comply with approved
standards and practices.

1. Make sure gas line is a separate line direct from the meter
unless the existing gas line is of sufficient capacity. Verify
pipe size with your gas supplier.

2. Use new, properly threaded black iron pipe free from
chips. If you use tubing, make sure the ends are square,
deburred and clean. Make all tubing bends smooth and
without deformation. Avoid flexible gas connections.
Internal diameter of flexible lines may not provide unit
with proper volume of gas.

3. Install a manual main gas shutoff valve at the unit's gas
inlet, outside of the unit.

4. Run pipe or tubing to the unit's gas inlet. If you use tubing,
obtain a tube to pipe coupling to connect the tubing to the
unit's gas inlet.

5. Install a sediment trap in the supply line to the unit's gas
inlet (see Figure 17).

6. Apply a moderate amount of good quality pipe compound
(do not use Teflon tape) to pipe only, leaving two end
threads bare.

7. Remove seal over gas inlet to unit.

8. Connect gas pipe to inlet of unit. Use wrench to support
gas manifold on the unit.

9. For L.P. gas, consult your L.P. gas supplier for expert
installation.

10. Ensure that all air is properly bled from the gas line before
starting the ignition sequence. Start up without properly
bleeding air from the gas line may require multiple reset
functions of the ignition control module to achieve proper
ignition.

 WARNING: Do not have any open flame in

proximity to the gas line when bleeding air from
the gas line. Gas may be present.

Figure 19 - Gas Train Drawing

For each elbow or tee, add equivalent straight pipe to total length from table below.

Gas Train and Controls

Note: The gas train and controls assembly provided on this
unit have been tested under the applicable American National
Standard to meet minimum safety and performance criteria
such as safe lighting, combustion and safety shutdown
operation.

Figure 19 shows a typical gas train.

TABLE-F

Installation and

Service Manual

17

COMBINATION VALVE

DOWNSTREAM

TEST VALVE

TO BURNERS

ADDITIONAL VALVES BASED

ON UNIT INPUTS

Btu/hr Distance From Meter (in feet)

Input 0-50 51-100 101-200 201-300 301-500

495,000 1 1/4" 1 1/4" 1 1/2" 2" 2"

645,000 1 1/4" 1 1/2" 2" 2" 2 1/2"

745,000 1 1/2" 2" 2" 2 1/2" 2 1/2"

985,000 2" 2" 2 1/2" 2 1/2" 3"

1,255,000 2" 2 1/2" 2 1/2" 3" 3"

1,435,000 2 1/2" 2 1/2" 3" 3" 3 1/2"

1,795,000 2 1/2" 3" 3" 3 1/2" 3 1/2"

2,065,000 2 1/2" 3" 3" 3 1/2" 4"

TABLE-F

Suggested Gas Pipe Size for Single Unit Installations

Diameter Pipe (inches)

3/4 1 1 1/4 1 1/2 2 3 4 5

Equivalent Length of Straight Pipe (feet)

22345101420

TABLE-G

Fittings to Equivalent Straight Pipe

INSTALLATION

Continued

Water heater models do not have downstream test valves, but
the rest of the gas train is represented by Figure 19.

Combination Gas Valves

These units fire in up to 2 stages of burner input. Each stage of
burner operation has a combination gas valve or series of gas
valves to cycle the gas supply on and off and regulate gas to the
burners. Each combination valve consists of a gas regulator and
two valve seats to meet the requirements for redundant gas
valves. The valve has a gas control knob that must remain in the
open position at all times when the unit is in service. The gas
control valve has pressure taps located on the inlet and discharge
sides of the valve. Manifold pressure is adjusted using the
regulator located on the valve. A manifold gas pressure tap for
each burner stage is located on the discharge side of the valve.

The manifold pressure is preset at the factory and adjustment
is not usually required. If you must adjust regulator pressure,
follow the instructions under Gas Manifold Pressure
Adjustment, page 19.

Venting of Combination Gas Valves

The combination gas valve/regulator used on all units is
equipped with an integral vent limiting orifice per ANSI
Z21.78. The vent limiter ensures that the volume of gas
emitted from the valve does not exceed the maximum safe
leakage rate allowed by agency requirements. Combination
gas valve/regulators equipped with integral vent limiters are

not required to have vent or relief lines piped to the outdoors.
The termination of the vent limited opening on the
combination gas valve/regulator complies with the safety code
requirements of CSD-1, CF-190(a) as shipped from the
appliance manufacturer without the installation of additional
vent lines.

Checking Gas Supply Pressure

Use the following procedure to check gas supply pressure.

1. Turn the main power switch to the "OFF" position.

2. Turn gas valve knobs to the "OFF" position.

3. Shut off gas supply at the field-installed manual gas cock
in the gas piping to the unit. If fuel supply is L.P. gas, shut
off gas supply at the tank.

4. Remove the 1/8" hex plug, located on “inlet” side of the
gas valve. You may also use a tapping on the field-installed
main manual gas cock or gas piping. Install a fitting in the
inlet pressure tapping suitable to connect to a manometer
or magnahelic gauge. Range of scale should be 14" w.c. or
greater to check inlet pressure.

5. Turn on gas supply at the manual gas cock, turn on L.P. gas
at tank if required.

6. Turn the power switch to the “ON” position.

7. Turn the gas valve knobs to the “ON” position. Set the
electronic temperature control or thermostat to call for
heat.

8. Observe the gas supply pressure as all burners are firing.
Ensure that inlet pressure is within the specified range. See
Connecting To Gas Supply, page 16 for minimum and
maximum gas supply pressures.

Hydronic Heating Boilers and
Domestic Water Heaters

18

Nominal Iron Length of Pipe In Straight Feet
Pipe Size,
(Inches) 10 20 30 40 50 60 70 80 90 100 125 150 175 200

TABLE - H

Multiple Unit Installations Gas Supply Pipe Sizing

3/4" 369 256 205 174 155 141 128 121 113 106 95 86 79 74

1" 697 477 384 328 292 267 246 226 210 200 179 164 149 138

1 1/4" 1,400 974 789 677 595 543 502 472 441 410 369 333 308 287

1 1/2" 2,150 1,500 1,210 1,020 923 830 769 707 666 636 564 513 472 441

2" 4,100 2,820 2,260 1,950 1,720 1,560 1,440 1,330 1,250 1,180 1,100 974 871 820

2-1/2" 6,460 4,460 3,610 3,100 2,720 2,460 2,310 2,100 2,000 1,900 1,700 1,540 1,400 1,300

3" 11,200 7,900 6,400 5,400 4,870 4,410 4,000 3,800 3,540 3,300 3,000 2,720 2,500 2,340

4" 23,500 16,100 13,100 11,100 10,000 9,000 8,300 7,690 7,380 6,870 6,150 5,640 5,130 4,720

Maximum capacity of pipe in thousands of BTU’s per hour for gas pressures of 14 Inches Water Column (0.5 PSIG) or less and a total system
pressure drop of 0.5 Inch Water Column (Based on NAT GAS, 1025 BTU’s per Cubic Foot of Gas and 0.60 Specific Gravity).

9. If gas pressure is out of range, contact your gas utility, gas
supplier, qualified installer or service agency to determine
the necessary steps to provide proper gas pressure to the
control.

10. If gas supply pressure is within normal range, remove the
gas manometer and replace the pressure tap fittings in the
gas control as indicated in the following steps.

11. Turn the power switch to the “OFF” position.

12. Turn gas valve knob to the “OFF” position.

13. Shut off gas supply at the manual gas cock in the gas
piping to the unit. If fuel supply is L.P. gas, shut off gas
supply at the tank.

14. Remove the manometer and related fittings from the
“inlet” side of the gas valve, replace 1/8" hex plug in the
gas valve and tighten.

15. Turn on the gas supply at the manual valve, turn on L.P.
gas at the tank if required.

16. Turn the power switch to the “ON” position.

17. Turn the gas valve knob to the “ON” position.

18. Set the electronic temperature control or thermostat to call
for heat.

 WARNING: After completing any testing

on the gas system, leak test all gas connections.
Apply a soap/water solution to all gas
connections while main burners are operating.
Bubbles forming indicate a leak. Repair all leaks
at once. Do not operate this unit with a leak in the
gas train, valves or related piping.

Check burner performance by cycling the system while you
observe burner response. Burners should ignite promptly.
Flame pattern should be stable, see Burner Flames, page 40.
Turn the system off and allow burners to cool, then cycle
burners again to ensure proper ignition and flame
characteristics.

Figure 20 - Measuring Gas Supply Pressure at
Combination Gas Valve

Gas Manifold Pressure Adjustment

IMPORTANT: The gas valves are referenced to
the fan pressurized chamber by a hose
connected from the vent of the gas valve
regulator to the chamber pressure tap located on
the front inside portion of the jacket. Reference
the drawings in this section for component and
connection points for pressure measurement.
The referenced chamber pressure must be
subtracted from the manifold pressure to obtain
actual net manifold pressure for normal
operation. A manometer or magnahelic gauge
legible in 0.1" increments up to 10 inches w.c. is
required to check and adjust the manifold
pressure. The regulator cover screw on the gas
valve must be in place and tight for the unit to
operate properly.

1. Remove screws that fasten the control panel access door
and remove the door.

Installation and

Service Manual

19

4

3

2

1

0

1

2

3

4

MANOMETER

GAS

VALVE

CONTROL

KNOB

INLET

OUTLET

1/8" HEX INLET
PRESSURE TAP

20

INSTALLATION

Continued

Figure 21 - Measuring Manifold Gas Pressure

2. Turn the power switch located in the lower left corner
behind the control panel access door to the “O” or “OFF”
position.

3. Remove the top front jacket access panels to access the gas
valve(s).

4. Locate the reference hose on the first gas valve which goes
from the vent fitting on the gas valve to the barbed fitting
on the deck of the unit (see Figure 21).

5. Remove the flexible cap from the barbed fitting on the
"tee" located in this line and hook one side of the
manometer, or (-) side of a magnahelic gauge, to this "tee".
Retain this cap for future use.

6. Remove the 1/8" hex plug from the manifold pressure tap
on the gas valve (see Figure 21). Retain plug for future use.

7. Install a fitting in this tap that is suitable for connection of
a hose to a manometer, or (+) side of a magnahelic gauge
(see Figure 21).

8. Turn the power switch to the “I” or “ON” position.

9. Push the reset button(s) for the ignition control(s), if
necessary.

10. Set the temperature control to call for heat (see Setting
Temperature Control, page 29).

11. Once the unit is firing, the manometer/magnahelic will
reflect the net manifold gas pressure. Compare this reading to
the respective value in TABLE-I for Natural Gas or Propane
Gas.

12. If adjustment is necessary, remove the regulator cover screw
on the gas valve. Note: If the gas valve under adjustment is
located on a manifold assembly monitored by an igniter, the
unit may shut down and recycle when the regulator cover
screw is removed. This is normal.

13. Turn the regulator adjustment screw “clockwise” to raise the
regulator gas pressure. Turn the regulator adjustment screw
“counterclockwise” to lower the regulator gas pressure.

14. Replace the regulator cover screw and make sure it is tight
for proper operation.

15. Read the value on the manometer/magnahelic and compare it
to the values in TABLE-I.

16. Repeat this adjustment procedure for each gas valve as
necessary to adjust to the proper manifold gas pressure.

17. Remove hoses, replace and tighten plugs and caps when
complete.

18. Replace top front upper jacket access panels and control
panel door in reverse order.

19. If proper ignition and burner operation is not achieved after
checking gas supply pressure, see Cleaning and
Maintenance, page 41 for Combustion Air Fan Adjustment.
Follow the procedure to adjust the combustion air fans as
necessary.

TABLE-H

CONNECTING TO WATER
SUPPLY

Inlet and Outlet Connections

For ease of service, install unions on the water inlet and water
outlet of the unit. The connection to the unit marked “Inlet” on
the header should be used for return from the system. The
connection on the header marked “Outlet” is to be connected
to the supply side of the system.

Hydronic Heating Boilers and
Domestic Water Heaters

Nat. Gas (495,000 - 745,000 Btu/hr) 1.8" w.c.

Nat. Gas (985,000 - 2,065,000 Btu/hr) 1.2" w.c.

LP Gas (495,000 - 2,065,000 Btu/hr) 4.6" w.c.

TABLE - I

NET MANIFOLD PRESSURE

Regulator Pressure Less
Front Chamber Pressure

Figure 22 - Water Connections

Relief Valve

This unit is supplied with a relief valve(s) sized in accordance
with ASME Boiler and Pressure Vessel Code, Section IV
("Heating Boilers"). The relief valve(s) is installed in the
vertical position and mounted in the hot water outlet. Place no
other valve between the relief valve and the unit. To prevent
water damage, pipe the discharge from the relief valve to a
suitable floor drain for disposal when relief occurs. Do not
install any reducing couplings or other restrictions in the
discharge line. The discharge line will allow complete drainage
of the valve and line. Manually operate the relief valves at least
once a year.

 CAUTION: Avoid contact with hot

discharge water.

Water Flow Switch

A water flow switch is factory installed. The flow switch is
wired in series with the 24 VAC safety control circuit at the
units terminal strip. This wiring connection installs the flow
switch in the 24 VAC safety circuit to prove water flow before
main burner ignition. The factory supplied flow switch is
installed in the outlet side of the front header. These units
require a minimum flow of 26 GPM to make the flow switch
and start burner operation. Ensure that the pump installed on
the unit will supply adequate flow to make the flow switch
contacts and operate the unit. A water flow switch meets most
code requirements for a low water cut off device on appliances
requiring forced circulation for operation.

Low Water Cutoff

(If Equipped)

If installing this unit above radiation level, you must install a
low water cut-off device at the time of appliance installation.
Electronic or float type low water cutoff controls are available
as a factory supplied option on all units. Inspect the low water
cutoff every six months, including flushing of float types. The
low water cutoff control is located on the control panel directly
behind the control panel cover.

The reset and test buttons (if equipped) are located on the
control panel.

CONNECTING TO
ELECTRICAL SUPPLY

This unit is wired for 120 VAC service. The unit, when
installed, must be electrically grounded in accordance with the
requirements of the authority having jurisdiction or in the
absence of such requirements, with the latest edition of the
National Electrical Code ANSI/NFPA No. 70. When the unit is
installed in Canada, it must conform to the CAE C22.1,
Canadian Electrical Code, Part 1 and/or local Electrical Codes.

1. Use only Type-T wire [63°F (35°C) rise] on all wiring
between the unit and field-installed devices.

2. Enclose line voltage wire exterior to the unit in approved
conduit or approved metal-clad cable.

3. The pump must run continuously when the unit is being
fired (hot water heating boilers must use the optional pump
delay if the pump is to be cycled. See Freeze Protection,
page 7 when cycling the pump). Water heaters use the
pump delay as standard in accordance with ASHRAE 90.1
requirements.

4. To avoid serious damage, do not energize the unit until the
system is filled with water.

5. Provide the unit with proper overload protection.

Installation and

Service Manual

21

INSTALLATION

Continued

Figure 23A - Models 495,000 - 745,000 Btu/hr Control
Panel Component Location Drawing

Figure 23B - Models 985,000 - 2,065,000 Btu/hr Control
Panel Component Location Drawing

External EMS Connection to Terminal
Strip for Stage Firing Control of Burners

This unit is equipped with a factory installed terminal strip for
connection of an energy management system (EMS) to the
burner stages. The EMS terminal strip is located in the unit's
junction box. Ensure that all wiring used for connection to this
terminal strip is properly sized per the recommendations in
TABLE-L. When connecting an EMS to this terminal strip to
sequence on each stage of burner operation, the unit's internal
thermostat or electronic sequencer should be set as an
additional high limit control. This will prevent problems
between the set points of the EMS and the boiler's internal
controller.

Terminal Strip Connection Options

(Models 985,000 - 2,065,000 Btu/hr Only)

Figure 24A shows the position of jumpers as shipped from the
factory for stand-alone operation of boilers or water heaters.

Figure 24B shows connections to the terminal strip for Remote
ON/OFF control of the boiler or water heater. The 1C-1NO
jumper must be removed when making these wiring
connections. This remote ON/OFF control will provide an
Enable/Disable signal to the unit and allow the unit to operate
based on the stage set points, until the remote ON/OFF signal
is cancelled.

Figure 24C shows the connections necessary to operate the
unit as a two-stage (High/Low Fire) boiler or water heater from
an Energy Management System (EMS). The actual set point
temperatures are controlled by the EMS. The High Fire Offset
on the electronic temperature control in the unit must be set to
zero and the set point must be set to a value which will function
as an upper limit for proper operation under this two-stage
control from an EMS.

Figure 24D shows the Continuous and Intermittent terminals.
External safety devices connected to these terminals will
function to protect the unit. Devices connected to the
Intermittent terminals (B1 and B2) are monitored only when
there is an active Call for Heat. Devices connected to the
Continuous terminals (A1 and A2) are monitored continuously
and will activate an alarm (if the unit is equipped with the
alarm option) anytime the safety device senses an abnormal
condition. An additional wire may be field-installed from these
safety devices to terminals A3 or B3 (as appropriate) to
activate an alarm (if the unit is equipped with the alarm
option).

Hydronic Heating Boilers and
Domestic Water Heaters

22

TABLE AMP Draw Data

Btu/Hr Approximate

Input Controls Fan Total Amps

495,000 4.6 3.4 8.0

645,000 4.6 3.4 8.0

745,000 4.6 3.4 8.0

985,000 4.6 3.4 8.0

1,255,000 4.6 3.4 8.0

1,435,000 4.6 3.8 8.4

1,795,000 4.6 3.8 8.4

2,065,000 4.6 3.8 8.4

TABLE - J

Nominal AMP Draw Data

IMPORTANT: Do not block access to the
electrical cover plate when installing electrical
conduit.

Figure 24A - Stand Alone Operation - Models 985,000 ­2,065,000 Btu/hr Only

Figure 24B - Remote On/Off Boiler or Water Heater ­Models 985,000 - 2,065,000 Btu/hr Only

Figure 24C - Two-Stage (High/Low Fire) Boiler or Water
Heater - Models 985,000 - 2,065,000 Btu/hr Only

Figure 24D - Field-Installed Safety Devices - Models
985,000 - 2,065,000 Btu/hr Only

BOILER SYSTEM PIPING

The drawings in this section show typical boiler piping
installations. Before beginning the installation, consult local
codes for specific plumbing requirements. Be sure to provide
unions and valves at the boiler inlet and outlet so it can be
isolated for service. You must install an air separation device in
the installation piping to eliminate trapped air in the system.
Locate a system air vent at the highest point in the system. The
system must also have a properly sized expansion tank
installed. Typically, an air charged diaphragm-type
compression tank is used. You must install the expansion tank
close to the boiler and on the suction side of the system pump
to ensure proper operation.

 CAUTION: This boiler system should not

be operated at less than 12 PSIG.

Provide suitable hangers or floor stands to support hot water
piping. The boiler alone should not support hot water piping.
Copper pipe systems are subject to considerable expansion and
contraction. Rigid pipe hangers could allow the pipe to slide in
the hanger resulting in noise transmitted into the system. Use
padding on rigid hangers installed with a copper system. Pipe
the boiler pressure relief valve to a suitable floor drain. See the
relief valve section in this manual.

 CAUTION: A leak in a boiler "system" will

cause the "system" to intake fresh water
constantly, which will cause the tubes to
accumulate a lime/scale build up. This will cause
a non-warrantable failure.

General Plumbing Rules

1. Check all local codes.

2. For serviceability of boiler, always install unions.

3. Always pipe the pressure relief valve to an open drain.

4. Locate system air vents at the highest point of system.

5. Expansion tank must be installed near the boiler and on the
suction side of the pump.

6. Support all water piping.

Water Connections: Heating
Boilers Only

Inlet and outlet water connections on models 495,000 ­745,000 Btu/hr have 2" NPT and on models 985,000 ­2,065,000 Btu/hr the inlet and outlet connections are
2 1/2" NPT.

Note: Field-installed reducing bushings may decrease flow
resulting in boiler noise or flashing to steam.

Installation and

Service Manual

23

INSTALLATION

Continued

Circulator Pump Requirements

This is a low mass, high efficiency hot water boiler which must
have adequate flow for quiet, efficient operation. Pump
selection is critical to achieve proper operation. A pump should
be selected to achieve proper system design water temperature
rise. Two heat exchanger head-loss charts (Figure 25A & 25B)
are provided to assist in proper pump selection. Also provided
is a System Temperature Rise Chart (TABLE-K). This table
provides GPM and boiler head-loss at various temperature
rises for each boiler based on Btu/hr input. Temperature rise is
the difference in boiler inlet temperature and boiler outlet
temperature while the boiler is firing.

Example: The boiler inlet temperature is 160°F (71°C) and the
boiler outlet temperature is 180°F (82°C), this means that there
is a 20°F (11°C) temperature rise across the boiler.

Heat Exchanger Pressure Drop Chart

Figure 25A - Pressure Drop Chart_Models 495,000 ­745,000 Btu/hr

Figure 25B - Pressure Drop Chart_Models 985,000 ­2,065,000 Btu/hr

Circulator Pump Specifications

1. Maximum operating pressure for pump must exceed
system operating pressure.

2. Maximum water temperature should not exceed nameplate
rating.

3. Cast iron circulators may be used for closed loop systems.

4. A properly sized expansion tank must be installed near the
boiler and on the suction side of the pump.

Circulator Pump Operation

(Heating Boilers Only)

The boiler pump should run continuously unless the boiler is
provided with the optional pump delay control system. This
optional pump control system is available as a factory-installed
option. External wire leads are furnished with this option to
allow the power supply for the pump to be switched across the
normally open contacts of the relay, allowing the control relay
to cycle the pump on each call for heat. The field installed
boiler pump (using the optional factory supplied pump control
system) must not exceed 10 AMPS at 120VAC. As shipped
from the factory, the optional control system is set to cycle the
boiler pump on at each call for heat before the burners fire and
run the pump for a 30 second period after the thermostat is
satisfied. This will remove any residual heat from the
combustion chamber before turning the pump off. See Wiring
Diagrams, page 47.

Pump Installation and Maintenance

For installation and maintenance information on the circulator
pump, refer to pump manufacturers instructions included in the
instruction package.

Primary/Secondary Boiler Piping

Boiler installations with a primary/secondary piping system as
shown in Figure 26 are recommended. This type of system
uses a dedicated pump to supply flow to the boiler only. This
secondary pump is sized based on desired boiler flow rate,
boiler head loss and head loss in the secondary system piping
only. A properly-sized system pump provides adequate flow to
carry the heated boiler water to radiation, air over coils, etc.
The points of connection to the primary system should be a
maximum of 12" (or 4 pipe diameters) apart to ensure
connection at a point of zero pressure drop in the primary
system. Multiple boilers may also be installed with a
primary/secondary manifold system as shown in Figure 27.
The multiple boilers are connected to the manifold in reverse
return to assist in balancing flow to multiple boilers.

 CAUTION: DO NOT allow the flow in the

primary loop to drop lower than the flow in the
secondary loop at any time during boiler
operation. Improper operation of the boiler(s)
and possible tripping of the high limits and relief
valves may occur.

Hydronic Heating Boilers and
Domestic Water Heaters

24

The installer must ensure that the boiler has adequate flow
without excessive temperature rise. Low system flow can
result in overheating of the boiler water which can cause short
burner ON cycles, system noise and in extreme cases, a
knocking flash to steam. These conditions indicate the need to
increase boiler flow by installation of a larger circulator pump
or the installation of a system bypass. System noise may also
indicate an oversized boiler.

 CAUTION: At no time should the system

pressure be less than 12 PSIG.

Figure 26 - Primary/Secondary Piping of a Single Boiler

Figure 27 - Primary/Secondary Piping of Multiple Boilers

Low Temperature Return Water
Systems

Any non-condensing boiler and venting system will develop
operational problems when exposed to inlet water
temperatures below 140°F. Lochinvar offers a low

temperature protection valve (LTV) that is factory preset to
maintain 140°F inlet water to the boiler regardless of the
system return water temperature. See Table K for available
valve kits.

Be sure to install the LTV valve per the piping diagrams
included with the kits. Alternatively, a bypass as shown in
FIG. 28 may be piped into the system. This piping is like a
primary/secondary boiler installation with a bypass in the
secondary boiler piping. Inlet water temperatures below 140°F
(60°C) can excessively cool the products of combustion
resulting in condensation on the heat exchanger and in the flue.
Condensation can cause operational problems, bad
combustion, sooting, flue gas spillage and reduced service life
of the vent system and related components. The bypass allows
part of the boiler discharge water to be mixed with the cooler
boiler return water to increase the boiler inlet temperature
above 140°F (60°C). This should prevent the products of
combustion from condensing in most installations. The bypass
should be fully sized with a balancing valve to allow for proper
adjustment. A valve must also be provided on the boiler
discharge, after the bypass. Closing this discharge valve forces
water through the bypass. Start boiler adjustment with the
bypass valve in the full open position and the boiler discharge
valve half open. A small amount of the higher temperature
boiler discharge water is mixed with the system water to
maintain the desired lower system temperature. A remote low
temperature range operator is recommended to control the
boiler operation based on the lower system temperature. (See
Terminal Strip Connection Options starting on
page 22).

Radiant Floor and Snow Melt
Heating Systems

This type of heating boiler application operates in a low
temperature range which requires a boiler bypass as described
under Low Temperature Bypass Requirements. A non-metallic
rubber or plastic tubing installed in a radiant (in floor) system
must have an oxygen barrier to prevent oxygen from entering
the system through the walls of the installed tubing. Excessive
oxygen absorption into the system will result in an accelerated
rate of corrosion causing a sludge buildup. This excessive
corrosion will also damage the boiler and system components.

Installation and

Service Manual

25

Table - K

LTV Valve Kits

Input

Btu/hr

LTV Valve Kit

495,000 - 745,000 VAL3048

985,000 - 2,065,000 VAL3047

EXPANSION TANK

LWCO
(OPTIONAL)

TO SYSTEM

AIR SEPARATOR

SYSTEM PUMP

FROM SYSTEM

MAKE-UP

WATER

PRV

12" OR 4 PIPE
DIAMETERS

SECONDARY

BOILER PUMP

INSTALLATION

Continued

Sludge formed as the result of excessive oxygen in the system
can restrict water flow resulting in a premature boiler failure.
Any boiler damage due to excessive oxygenation is non­warrantable.

Figure 28 - Boiler with Low Temperature Bypass Piping

Installation with a Chilled Water
System

Pipe refrigeration systems in parallel. Install duct coil
downstream at cooling coil. Where the hot water heating boiler
is connected to a heating coil located in the air handling units
which may be exposed to refrigeration air circulation, the
boiler piping system must be equipped with flow control
valves or other automatic means to prevent gravity circulation
of the boiler water during the cooling cycle. The coil must be
vented at the high point and hot water from the boiler must
enter the coil at this point. Due to the fast heating capacity of
the boiler, it is not necessary to provide a ductstat to delay
circulator operation. Also, omit thermostat flow checks as the
boiler is cold when heating thermostat is satisfied. This
provides greater economy over maintaining standby heat (see
Figure 29).

Figure 29 - Installation with a Chilled Water System

Hydronic Heating Boilers and
Domestic Water Heaters

26

System Temperature Risased on Btu/hr Input

T T T T T T

10ºF 20ºF 30ºF 40ºF 50ºF 60ºF

Input Output GPM FT. HD GPM FT.HD GPM FT.HD GPM FT.HD GPM FT.HD GPM FT.HD

495,000 400,950 80+ * 40 4.0 27 1.6 20 0.7 16 0.6 13 0.6

645,000 522,450 129+ * 52 5.1 35 3.0 26 1.6 21 0.8 17 0.6

745,000 603,450 149+ * 60 * 40 4.0 30 2.3 24 1.2 20 0.7

985,000 831,600 197+ * 80 5.2 53 2.4 40 1.4 32 1.0 27 0.8

1,255,000 1,058,400 251+ * 102+ * 68 4.3 51 2.5 41 1.6 34 1.1

1,435,000 1,209,000 288+ * 116+ * 78 6.0 58 3.7 47 2.2 39 1.7

1,795,000 1,512,000 360+ * 146+ * 97+ * 73 6.2 58 4.2 49 2.4

2,065,000 1,738,800 414+ * 168+ * 112+ * 84 8.7 67 6.0 56 4.5

+ These flow rates exceed recommended flow rates of boiler. If these system temperature rises are used, an external piping by-pass must be installed.
* These foot head calculations exceed the maximum allowable flow rate of the boiler. Requires Cupro-Nickel heat exchanger.

TABLE - L

System Temperature Rise Chart Based on Btu/hr Input

EXPANSION

TANK

LOW WATER

FLOW SWITCH

PUMP

HEATING AND
COOLING COIL

OUT

IN

BOILER

GAS

SUPPLY

WATER

SUPPLY

CHILLER

Boiler Flow Rate

 CAUTION: The maximum flow rate for

models 495,000 - 745,000 Btu/hr is 60 GPM and
90 GPM on 985,000 - 2,065,000 models. Do not
exceed the maximum flow rate of the heating
boiler.

If higher flow rates are required through the boiler,
an optional Cupro-Nickel heat exchanger is
available. When using a Cupro-Nickel heat
exchanger, GPM can be increased by 30 percent.
Consult the factory for specific application
requirements.

The heat exchanger is generally capable of operating within
the design flow rates of the building heating system. Should
the flow rate exceed the maximum allowable flow rate through
the boiler an external bypass must be installed. The bypass
should be fully sized with a balancing valve to allow for proper
adjustment of flow. Flow rate can be determined by measuring
the temperature rise through the boiler.

Boiler Bypass Requirements

The installer must ensure that the boiler is supplied with
adequate flow without excessive temperature rise. It is
recommended that this boiler be installed with a bypass in the
piping if the maximum recommended flow rate is exceeded.
The bypass will help to ensure that the boiler can be supplied
with adequate water flow. Flow rates exceeding the maximum
recommended flow will result in erosion of the boiler tubes. A
typical bypass with a valve is shown in Figure 30 will allow
control of boiler flow.

Temperature/Pressure Gauge

This boiler is equipped with a dial type temperature/pressure
gauge. This gauge is factory installed in the outlet side of the
heat exchanger. The gauge has one scale to read system
pressure and a separate scale to read water temperature in
degrees, Fahrenheit.

Figure 30 - Boiler Bypass Piping for High Flow Systems

Filling the System

All air must be purged from the system for proper operation.
An air scoop and air vent must be located close to the boiler
outlet and there should be a minimum distance between the
cold water feed and the system purge valve.

1. Close all drain cocks and air vents.

2. Open the makeup water valve and slowly fill the system.

3. If a makeup water pump is employed, adjust the pressure
to provide a minimum of 12 psi at the highest point in the
system. If a pressure regulator is also installed in the line,
it should be adjusted to the same pressure.

4. Close all valves. Purge one circuit at a time as follows:

A. Open one circuit drain valve and let the water drain

for at least five minutes. Ensure that there are no air
bubbles visible in the water stream before closing
the drain valve.

B. Repeat this procedure for each circuit.

5. Open all valves after all circuits have been purged. Make
sure there are no system leaks.

 CAUTION: Do not use petroleum based

stop leak products. All system leaks must be
repaired. The constant addition of make-up water
can cause damage to the boiler heat exchanger
due to scale accumulation. Scale reduces flow
and heat transfer, causing overheating of the
heat exchanger.

6. Run the system circulating pump for a minimum of 30
minutes with the boiler turned off.

7. Open all strainers in the system and check for debris.

Installation and

Service Manual

27

INSTALLATION

Continued

8. Recheck all air vents as described in step 4.

9. Inspect the liquid level in the expansion tank. The system must
be full and under normal operating pressure to ensure proper
water level in the expansion tank. Ensure that diaphragm type
expansion tanks are properly charged and not water logged.

10. Start the boiler according to the operating instructions in this
manual. Operate the system, including the pump, boiler and
radiation units, for one hour.

11. Recheck the water level in the expansion tank. If it exceeds
half the tank volume, open the tank to reduce the water level.
Recheck pressure charge on diaphragm type tanks.

12. Shut down the entire system and vent all radiation units and
high points in the system.

13. Close the water makeup valve and check the strainer and
pressure reducing valve for sediment or debris. Reopen the
water makeup valve.

14. Verify system pressure with the boiler pressure gauge before
beginning regular operation.

15. Within three days of startup, recheck and bleed all air vents
and the expansion tank using these instructions.

WATER TREATMENT

In hard water areas, water treatment should be used to reduce
the introduction of minerals to the system. Minerals in the
water can collect in the heat exchanger tubes and cause noise
on operation. Excessive build up of minerals in the heat
exchanger can cause a non-warrantable failure.

OPERATION

FOR YOUR SAFETY READ
BEFORE OPERATING

 WARNING: If you do not follow these

instructions exactly, a fire or explosion may
result causing property damage, personal injury
or loss of life.

A. This appliance does not have a pilot. It is equipped with an

ignition device which automatically lights the burner. Do not
try to light the burner by hand.

B. BEFORE OPERATING, smell around the appliance area

for gas. Be sure to smell next to the floor because some gas
is heavier than air and will settle to the floor.

WHAT TO DO IF YOU SMELL GAS

• Do not try to light any appliance.

• Do not touch any electric switch; do not use
any phone in your building.

• Immediately call your gas supplier from a
neighbors phone.

• Follow the gas supplier's instructions.

• If you cannot reach your gas supplier, call the
fire department.

C. Use only your hand to turn the gas control lever. Never use

tools. If the lever will not turn by hand, don't try to repair it,
call a qualified service technician. Force or attempted repair
may result in a fire or explosion.

D. Do not use this boiler if any part has been under water.

Immediately call a qualified service technician to replace the
boiler. The possible damage to a flooded boiler can be
extensive and present numerous safety hazards. Any
appliance that has been under water must be replaced.

Lighting Instructions

1. STOP! Read the safety information.

2. Set the temperature control to the desired settings (see
Setting Temperature Control, page 29).

3. Loosen the knurled knob at the bottom of the control panel
cover (see Figure 31).

4. Grasp the bottom of the control panel cover and pull out
and down.

5. Locate the ON/OFF switch inside the control area. The
switch is located to the left of the control panel (see
Figure 32).

6. Turn the power switch to the “OFF” position.

7. This unit is equipped with an ignition device which
automatically lights the burners. Do not try to light the
burners by hand.

Hydronic Heating Boilers and
Domestic Water Heaters

28

Figure 31 - Control Panel Cover

Figure 32 - ON/OFF Switch

8. Turn the manual gas cock clockwise to the “OFF” position.

9. Wait five (5) minutes to clear out any gas. If you smell gas,
STOP! Follow “B” in the safety information. If you do not
smell gas, go on to the next step.

10. Turn the manual gas cock counterclockwise to the “ON”
position.

11. Turn the power switch to the “ON” position.

12. Reinstall the control panel cover. Tighten the knurled knob
at the bottom of the control panel cover.

13. If the unit will not operate, follow the instructions “To
Turn Off Gas To Appliance” and call your service
technician or gas supplier.

To Turn Off Gas To Appliance

1. Remove the control panel cover to access control panel.

2. Turn power switch to "OFF" position.

3. Turn the manual gas cock clockwise to the "OFF" position.

 WARNING: Should overheating occur or

the gas fail to shut off, turn off the manual gas
control valve to the unit.

Figure 33 - Combination Gas Valve

SETTING TEMPERATURE
CONTROL

Note: The temperature controller is preset at the factory with
test settings. You may need to adjust the settings to meet your
specific needs.

 WARNING: Return water temperatures

must not be less than 140°F. If lower return water
temperatures are required, follow the instructions
for Low Temperature Return Water Systems on
page 25.

Locating Temperature Control

The temperature control is located behind the combustion air
inlet panel on the left front of the unit (see Figure 34). Follow
the steps below to access the temperature control.

1. Loosen the knurled knob at the bottom of the control panel
cover.

2. Pull the bottom of the panel out and down to remove.

Installation and

Service Manual

29

OPERATION

Continued

Figure 34 - Locating Temperature Control

Temperature Control Settings

There are three setting knobs on the temperature control unless
your unit is specified as a boiler only with an outdoor air reset
option. If your unit is a boiler only with an outdoor air reset
option, there are additional controls for this option. They are
explained under Outdoor Air Reset Option, page 31.

The three setting knobs on the temperature control are for Set
Point, Differential, and High-Fire Offset (see Figure 35).

Maximum Set Point Determination

The maximum set point for the control is factory set. Boilers
are set to 230°F max., water heaters are set to 190°F max., and
specialty state and local codes to 200°F.

These maximum set points are established by not
cutting/cutting the OJ1 and OJ2 jumpers located on the right
side of the temperature controller (see Figure 35). The
maximum set point is determined as shown in TABLE-M.

Figure 35 - Temperature Control Setting Knobs

TABLE-L

Maximum

Setpoint

n

Note: Anytime that OJ1 is the only jumper cut, a new
overlay is required under the Set Point knob on the
temperature controller because the scale has changed to a
maximum of 190°F.

Anytime the OJ2 jumper is cut (with or without OJ1), a
new overlay is required under the Set Point knob on the
temperature controller because the scale has changed to a
maximum of 200°F.

Set Point

The Set Point knob specifies the target water temperature in
degrees, Fahrenheit. After the water temperature reaches the
set point, the temperature control shuts off the burners.

Differential

The Differential specifies the number of degrees below the set
point that the control will allow the water temperature to drop
before it brings the unit back on again.

Hydronic Heating Boilers and
Domestic Water Heaters

30

Max.

OJ1 OJ2 Set Point

Connected Connected 230°F

Cut Connected 190°F

Connected Cut 200°F

Cut Cut 160°F

TABLE - M

Maximum Set Point Determination

High-Fire Offset

The temperature control operates a two-stage firing system.
The two stages are High-Fire and Low-Fire. High-Fire
operates all burners while Low-Fire operates approximately
one-half of the burners.

The High-Fire knob specifies the number of degrees below set
point that the High-Fire stage shuts down. At that point, the
unit will continue to operate at the Low-Fire stage until the set
point is reached.

The High-Fire offset knob has settings between 0°F and 20°F.
If set at 0°F, the High-Fire offset is disabled and the unit will
operate at the High-Fire stage until the set point is reached and
the temperature control shuts the unit off.

When the High-Fire offset knob is set to 0 or 1, the unit will
light at Low Fire and operate for approximately 10 seconds
before the High-Fire stage actuates. When set to 2 or above,
the unit will operate at Low Fire for 2 minutes before the High
Fire stage actuates.

Outdoor Air Reset Option

For boilers ordered with the Outdoor Air Reset option, there is
an additional control (see Figure 36). There are three setting
knobs for Shutdown, Outdoor Air Max., and Ratio. There is
also a switch to turn the outdoor air sensor On or Off. An O.A.
Sensor is also included.

Shutdown

The Shutdown knob specifies the outdoor air lockout
temperature at which the control would prevent the unit from
operating. This feature can be enabled/disabled with the O.A.
Shutdown switch.

Outdoor Air Max (O.A. Max)

The O. A. Max knob allows a reset up to the maximum outdoor
air temperature specified by this knob setting. When the
outdoor air temperature is above the specified setting, the unit
will not function in the O.A. Reset Mode, but will continue to
run at the selected set point temperature.

Note that the set point knob will now indicate the “minimum”
boiler temperature. Target temperature is determined by the
ratio and outdoor air temperature below the O.A. Max setting.

Ratio

The Ratio knob allows the control over the reset ratio to be
used during Outdoor Air Reset. The allowable ratios are as low
as 0.5:1 or as high as 1.5:1.

Selecting the 0.5:1 ratio will increase the set point 0.5°F for
every 1.0°F drop in outdoor air temperature up to the
maximum set point temperature.

Selecting the 1.5:1 ratio will increase the set point 1.5°F for
every 1.0°F drop in outdoor air temperature up to the
maximum set point temperature.

See Figure 37 for an outdoor air reset chart example.

Figure 36 - Optional Outdoor Air Reset Control

Installation and

Service Manual

31

R6

R8

R16

R15

C7

C9

C10

VR2

VR3

OJ1

OJ2

D4

J4

CN1

CN2

CN9

CN7

CN8

CN3

CN4

CN5

CN6

W1

TST2314

20

15

10

5

(F-)0

15

14

13

12

11

10

9

8
7
6

5

OFF

120

240

220

200

160

140

SETPOINT

DIFFERENTIAL

HIGH-FIRE

OFFSET

(c)2002 L.C.

O.A. SENSOR

ON

O.A. SHUTDOWN

0.9

0.8

0.7

0.6

0.5

9

8

7

6

VR2

5

TST2314

CN1

ENABLE

SW1

DISABLE

1.0

VR2

RATIO

11

15

12

1.1

13
14

1.2

1.4

1.5

1.3

W1 W2

5

R16

R15

(F-)0

HIGH-FIRE

CN2

R4R4R6

C7

W3

10

VR3

OFFSET

CN3

CN4

CN5

CN6

(c)2002 L.C.

CN7

CN8

CN1

140

120

D4

45

W1

SHUTDOWN

50

45

40
O.A. MAX.

160

OFF

SETPOINT

55

50

60

65

VR3

7040

55

60

65

VR1

70

200

220

240

DIFFERENTIAL

OJ1

C10

OJ2

C9

J4

R8

CN9

15

20

OPERATION

Continued

Temperature Control Sensors

This is a two-stage temperature control that controls the burner
ignition, pump, and alarm functions. This temperature
controller can measure up to three different sensor inputs,
depending upon how the unit is set up. They are as follows:

1. Inlet Water Temperature Sensor

2. Multi-Purpose Temperature Sensor

3. Outside Air Temperature Sensor

Inlet Water Temperature Sensor

This sensor measures the inlet water temperature coming into
the unit.

Multi-Purpose Temperature Sensor

Depending upon how your unit is set up, this sensor can be
used as a system sensor or a tank sensor.

Outdoor Air Temperature Sensor

This sensor is only available on boiler units with an outdoor air
reset option. This allows you to tie boiler operation to the
outdoor air temperature. As outside temperatures drop, the
control will increase the temperature setting of the boiler. As
outdoor temperatures rise, the control will decrease the
temperature to the selected set point of the boiler. You can set
the control to shut the boiler off when a desired outdoor air
temperature level is reached.

Figure 37 - Outdoor Air Reset Chart Example

Boiler Application

Standard boiler units are shipped with two sensors; the inlet
water temperature sensor and the multi-purpose temperature
sensor. The multi-purpose sensor should be used as a system
sensor. Boilers with the outdoor air reset option also have an
outside air temperature sensor.

Water Heater Application

Water heater units are shipped with two sensors; the inlet water
temperature sensor and the multi-purpose temperature sensor
to be used as a tank sensor.

Placement of Sensors

Inlet Temperature Sensor

The inlet water temperature sensor is placed into the inlet
bulbwell on the boiler. This sensor is installed by the factory in
new units. Make sure to insert the sensor all the way into the
bulbwell, leaving no air pocket between the front surface of the
sensor and the back of the bulbwell. Air pockets are thermally
non-conductive and will cause sensors to not read accurately.

System Sensor

This is used for boiler applications. This sensor will control the
boiler operation based upon the water temperature within the
building loop.

Tank Sensor

This is used in water heating applications. Place the sensor in
the water storage tank to measure water temperature. For more
information on mounting the sensor, see Remote Mounting of
Sensors, page 33.

Outside Air Temperature Sensor

The outside air temperature sensor will only be used for boiler
systems. The outside air sensor is optional. You must purchase
the sensor from the appliance manufacturer. The sensor comes
with a housing that helps protect the sensor from the elements.
Mount the air sensor housing under the eve of the roof. Make
sure the housing is out of direct sunlight. This will ensure that
the sensor will accurately read the true outdoor temperature.
For more information on mounting the sensor, see Remote
Mounting of Sensors, page 33.

Hydronic Heating Boilers and
Domestic Water Heaters

32

Remote Mounting of Sensor

You must mount the outside air temperature sensor outside the
building. To mount remote sensors, follow the guidelines
below. Take care to correctly wire sensors to the unit. Erratic
temperature readings can be caused by poor wiring practices.
Twist the wires between the unit and the remote sensor. Turn
wires at least three or four turns per linear foot of wiring. This
provides common mode rejection of some types of electrical
interferences.

1. Do not route temperature sensor wiring with building
power wiring.

2. Do not locate temperature sensor wiring next to control
contactors.

3. Do not locate temperature sensor wiring near electric
motors.

4. Do not locate temperature sensor wiring near welding
equipment.

5. Make sure good mechanical connections are made to the
sensor, any interconnecting wiring and the controller.

6. Do not mount sensor with leadwire end pointing up in an
area where condensation can occur.

7. Use shielded wiring to connect the sensor to the control
when the possibility of an electrically noisy environment
exists. Shielded cable is recommended on all cable runs of
more than 25 feet in length.

Note: Ground the cable shield at the connection to the boiler
temperature control only. Do not ground the shielded cable at
the sensor end.

To maintain temperature accuracy, sensor wires should be at
least 18 AWG, see Table N below.

HOT SURFACE IGNITION SYSTEM

Hot Surface Igniter and Ignition
Control Module

This unit has one ignition module and one hot surface igniter.

Figure 38 - Hot Surface Igniter

Figure 39 - Hot Surface Ignition Control Module

Installation and

Service Manual

33

Wire Maximum

Gauge Allowable Length

12 GA 100 ft

14 GA 75 ft

16 GA 50 ft

18 GA 30 ft

TABLE - N

Remote Wire Connection

 Caution: The igniter is extremely fragile, be very
careful when removing. A faulty or damaged hot surface
igniter MUST BE replaced with a Lochinvar PLT3400
igniter. Do not use general purpose field replacement
igniters.

FC+FC-

P3

DS2

+

F2

F1

OPERATION

Continued

Hot Surface Ignition Control Module

Ignition Module Lockout Functions

The ignition module may lockout in either a hard-lockout
condition, requiring pushing of the reset button to recycle the
control, or a soft-lockout condition which may recycle after an
approximate five-minute waiting period. This soft-lockout
condition is intended to allow self-correcting faults to correct
themselves and permit normal operation. A typical hard­lockout fault is a flame failure condition. An ignition module
that is in a hard-lockout condition may only be reset by
pushing the reset button next to the ignition control or the
"RESET" button on the diagnostic panel on the left end of the
unit. Upon a flame failure, the reset button is only active after
the control module has completed its post-purge cycle. Turning
main power "OFF" and then "ON" or cycling the thermostat
will not reset a hard-lockout condition. Wait five seconds after
turning on main power before pushing the reset button when
the ignition module is in a hard lockout. The ignition module
will go into a soft lockout if conditions of low air, low voltage
or low hot surface igniter current are present. A soft-lockout
condition will operate the combustion air fans for the post
purge cycle and then the ignition module will pause for
approximately five minutes. At the end of this timed pause, the
ignition module will attempt a new trial for ignition sequence.
If the soft-lockout fault condition has subsided or has been
corrected at the end of the timed pause, main burner ignition
should be achieved with the resumption of the normal trial for
ignition sequence. If the control sensed fault is not corrected,
the ignition module will continue in the soft-lockout condition.
If the electronic thermostat opens during the soft-lockout
period, the ignition module will exit soft lockout and wait for
a new call for heat from the thermostat. A soft-lockout
condition may also be reset by manually cycling the thermostat
or turning the main power switch "OFF" and then "ON" after
the control sensed fault has been corrected.

Diagnostic Status Indication

The ignition module has an LED which indicates the status of
the safety circuits. A remote Ignition Module Status indicating
light is wired from the ignition module Status LED and
mounted on the side diagnostic panel. The flashing operation
of this light indicates the diagnostic status of the ignition
control module. The status LED, mounted on the ignition
module flashes a code sequence from the Ignition Module to
indicate the status of the ignition process. See TABLE-N for
the flashing diagnostic status codes as signaled by the ignition
module.

Ignition and Control Timings

Proven Pilot Hot Surface Ignition System F9 is standard on
models 495,000 through 2,065,000 Btu/hr and M9 is optional
on models 495,000 through 2,065,000 Btu/hr with One Hot
Surface Ignition Module.

Hot Surface Ignition Module Timings (Nominal)

Prepurge:

15 Seconds

Hot Surface Igniter Heat-up Time:

25- 35 seconds

Main Burner Flame Establishing Period:

4 Seconds

Failure Response Time:

0.8 Seconds at less than 0.5 µA flame current

Flame Current:

5 - 15 µA

Time Delay Between Stages 1&2:

10 Seconds

Post-purge:

30 Seconds

Pump Delay Timing:

30 Seconds after burner shutdown.

Hydronic Heating Boilers and
Domestic Water Heaters

34

OPERATION AND DIAGNOSTIC
LIGHTS

The diagnostic control panel has up to 6 indicating and
diagnostic lights to show all major steps of operation and
control sensed malfunctions. This panel is located on the left
end of the unit.

Figure 40 - Operation/Diagnostic Lights

Installation and

Service Manual

35

Code Sequence Condition

Constant ON System OK, no faults present.
Constant OFF Possible control fault, check power;

LED may be effective, do not replace
control if all operational sequences
function properly, see Trouble Shooting
Guide.

One Flash Low Air, check air pressure switch and

hoses to pressure sensing points, fan,
venting and sealing of pressurized
chamber. Note:Brief flashing normal on
fan start-up/proving.

Two Flashes Flame without call for heat, check for a

gas valve stuck in the open position, air,
venting, burners and the combustion
process. Fan will remain on.

Three Flashes Lockout due to flame failure, push reset

button on inner control panel after
correcting ignition problem. Initial heater
start up without properly bleeding air
from the gas line may require multiple
reset functions to achieve proper ignition.

Four Flashes Igniter failure, igniter will not maintain

minimum 2.75 amp current draw, caused
by, low voltage, bad wiring/continuity,
high resistance or igniter failure.

Five Flashes Power supply problem, check for low

supply voltage or transformer output less
than 18VAC.

Six Flashes Replace ignition module, internal

fault.

TA

TABLE - O

Status LED Diagnostic Codes

Code
Sequence Condition Lights

Prepurge Operation of combustion

air fan before ignition on

stages 1 and 2.

Trial for Ignition Hot surface igniter

preparing to light burners.

Stage 1 On Burners for stage 1 operating.

Stage 2 On Burners for stage 2 operating.

(985,000 - 2,065,000 Btu/hr)

Status Remote status light for

ignition module.

Alarm Indicates flame failure on

the ignition module and
will indicate additional
alarms if the alarm of any
failure option is purchased.

TABLE - P

Status LED Diagnostic Codes

Models 495,000 - 745,000 Btu/hr

Models 985,000 - 2,065,000 Btu/hr

DOMESTIC WATER
HEATERS

This section applies only to those units used to supply potable
hot water for domestic use. The hot water supply boiler must
be installed with a storage tank.

This section contains specific instructions for those units used
to supply domestic hot water. All warnings, cautions, notes and
instructions in the general installation and service sections
apply to these instructions. Hot water supply heaters are
designed for installation with a properly sized storage tank.
The use of a properly sized pump and the control of water
velocity, as explained below, are important for correct
operation of your water heater.

Water Velocity Control

IMPORTANT: To ensure proper velocity through
the heat exchanger, you must regulate the
temperature rise across the heat exchanger from
inlet to outlet. Do this upon initial installation and
periodically recheck. The correct temperature
rise across the heat exchanger ensures proper
velocity in the tubes. This will yield long life and
economical operation from your hot water
heater. Excessive lime build up in the tube is
caused by too low of velocity through the tubes.
Excessive pitting or erosion in the tube is caused
by too high of velocity through the tubes. Take
care to measure temperature rise and maintain a
velocity as follows:

1. With the pump running and the water heater off, the inlet
and outlet thermometers should read the same
temperatures. If they do not, an adjustment must be made
to your final calculation.

2. Turn the water heater “On” and allow time for the
temperature to stabilize. Record the difference between the
inlet and outlet temperatures. This difference will be the
“temperature rise”.

3. Compare the temperature rise on the heater with the
required temperature rise in TABLE-Q. Should adjustment
be needed, proceed as follows:

If the temperature rise is too high, the water velocity
is too low. Check the following:

1. Check for restrictions in the outlet of the water heater.

2. Be sure all valves are open between the water heater and
the tank.

3. Check the pump to be sure it is running properly and that
the pump motor is running in the proper direction (see
arrow on volute housing).

4. Be sure the installed circulation pipes between the water
heater and storage tank are not less than 2 1/2" in diameter
on models 985,000 - 2,065,000 Btu/hr.

5. Common manifold piping for multiple unit installations
will require larger minimum pipe sizes and tank circulating
tappings to ensure proper flow. See TABLE-R.

If the temperature rise is too low, the water velocity
is too high. Adjust as follows:

1. Slowly throttle the valve on the outlet side of the water
heater until the temperature rise is steady at the required
temperature rise as noted in TABLE-Q.

2. Sustained high water velocity and low temperature rise
may result in pitting or erosion of the copper tubes in the
heat exchanger. This is a non-warrantable failure.
Temperature rise must be properly adjusted to achieve the
specified flow rate.

Required Temperature Rise

Based on heating potable water with a hardness of 5 to 25
grains per gallon and/or total dissolved solids not exceeding
350 ppm, see Water Chemistry, page 37.

Hydronic Heating Boilers and
Domestic Water Heaters

36

Btu/hr Temperature

Input Rise °F

495,000 15

645,000 19

745,000 22

985,000 18

1,255,000 23

1,435,000 26

1,795,000 32

2,065,000 37

TABLE - Q

Temperature Rise Chart

Installation and

Service Manual

Water Chemistry

The required temperature rise and the standard pump sizing are
based on the heating of potable water with a hardness of 5 to
25 grains per gallon and a total dissolved solids not exceeding
350 ppm. Consult the appliance manufacturer when heating
potable water exceeding these specifications. Heating of high
hardness and/or high total dissolved solids water will require a
larger circulating pump, an optional cupro-nickel heat
exchanger and a revised temperature rise specification based
on the water chemistry of the water to be heated. Water with a
hardness of less than 5 grains per gallon will usually have a
low pH which can be aggressive and corrosive causing non­warrantable damage to the heater, pump and associated piping.
Corrosion due to water chemistry generally shows up first in
the hot water system because heated water increases the rate of
corrosive chemical reactions.

Figure 41 - Typical Water Heater Piping with Storage Tank

Pipe Size Requirements

Table-R, pipe sizing chart provides the minimum pipe size for
common manifold piping to ensure adequate flow.

ABLE-P

Pipe Sizing Chart

Circulating Pump

1. The water heater must be connected to a properly sized
pump that circulates water between the heater and storage
tank.

2. The pump is sized to heater input and water hardness. Care
should be taken to size the pump correctly. See Water
Chemistry on this page.

3. The water heater is equipped with a factory-supplied pump
delay system in accordance with the requirements of the
latest edition of ASHRAE 90.1.

4. Lubricate the pump to the manufacturer’s
recommendations. Pump damage due to inadequate
lubrication is non-warrantable.

5. Standard water heaters are furnished with the following
circulating pump. Mount the pump on the unit's inlet water
connection.

This pump is sized based on installation of a single storage
tank and heater in close proximity. If the number of fittings
and straight pipe exceeds the quantities shown in this section,
a larger pump will be required.

The standard pump selection is based on the following pipe
and fittings from the unit to the storage tank:

37

495,000 - 745,000 985,000 - 2,065,000

Number Common Number Common

of Pipe of Pipe

Units Size (Min) Units Size (Min)

1 2" 1 2 1/2"

23"2 4"

33"3 4"

44"4 5"

55"5 6"

65"6 6"

TABLE - R

Pipe Sizing Chart

495,000 -745,000 Btu/hr Models

1/4 HP, 120 VAC, 5.8 Amps

985,000 -2,065,000 Btu/hr Models

1/2 HP, 120 VAC, 7.4 Amps

COLD WATER

SUPPLY

EXPANSION TANK

MIXING VALVE

HOT WATER

SUPPLY

RELIEF

VALV E

RELIEF

LOCK-TEMP

STORAGE

TAN K

DRAIN

VALV E

(IF REQUIRED)

BUILDING

RETURN

CIRCULATING

PUMP

DOMESTIC WATER
HEATERS Continued

6 90° elbows 2 ball valves

2 unions 1 cold water tee

Not more than 45 feet of straight pipe.

IMPORTANT: For every elbow and tee in excess
of those shown above, deduct 5 feet from
maximum allowable straight pipe in heater to
tank circulating loop.

Minimum Pump Performance

This is based on heating potable water with a hardness of 5 to
25 grains per gallon and/or total dissolved solids not exceeding
350 ppm. See Water Chemistry, page 37.

LE-Q

Minimum Pump Performance

Heat Exchanger

This is a highly sophisticated heat exchanger, designed to carry
water in such a way that it generates a scouring action which
keeps all interior surfaces free from build up of impurities. The
straight line, two pass design of the tubes sends water into the
headers at a properly rated velocity. The configuration of the
headers, in turn, creates a high degree of turbulence which is
sufficient to keep all contaminants in suspension. This
“scouring action” provides greater cost savings for owners.
Tubes are always able to transfer heat at peak efficiency. Every
surface within this water containing section is of a non ferrous
material, providing clear, clean, rust free hot water. Straight
copper tubes finned on the outside for maximum heat transfer
and coated cast iron one piece cored headers make up an
entirely rust proof unit. On all models, header inspection plugs
can be removed for field inspection and cleaning of copper
tubes. The entire heat exchanger may be easily removed from
the unit.

Potable Hot Water Temperature
Control Settings

Domestic Water Temperatures

 WARNING: You must take adequate care

to prevent scald injury when storing water at
elevated temperatures for domestic use.

This unit has an adjustable temperature control to maintain the
desired water temperature set point. See Setting Temperature
Control, page 29, for instructions to program the temperature
control. The temperature control is factory preset at
approximately 125°F (52°C) or less. Households with small
children or invalids may require 120°F (49°C) or lower
temperature hot water to reduce risk of scald injury.

Operate this high efficiency hot water heater at a temperature
setting high enough to prevent condensing of the products of
combustion on the unit's heat exchanger or in the attached
venting system. A water temperature setting that is above the
dew point of the gas combustion products should prevent
condensate formation.

 WARNING: To guard against scald injury,

you must use a properly-sized thermostatic
mixing valve to supply domestic hot water at
temperatures less than 125°F (52°C).

Storing the water at a higher temperature and thermostatically
mixing the water increases the available quantity of mixed hot
water, greatly reducing the possibility of condensate forming
on the heat exchanger or in the venting system and helps
prevent water born bacteria growth.

Some states may require a lower water temperature setting for
specific applications. Check local codes or your gas supplier
for domestic hot water temperature requirements.

Hydronic Heating Boilers and
Domestic Water Heaters

38

BTU/hr Input GPM Ft.Hd.

495,000 - 745,000 60 10

985,000 - 2,065,000 90 15

TABLE - S

Minimum Pump Performance

• Water temperature over 125°F (52°C)
can cause severe burns instantly or
death from scalds.

• Children, disabled and elderly are
at highest risk of being scalded.

• See instruction manual before
setting temperature at heating
appliance.

• Feel water before bathing or showering.

• If this appliance is used to produce
water that could scald if too hot,
such as domestic hot water use,
adjust the outlet control (limit) or use
temperature limiting valves to obtain
a maximum water temperature of
125°F (52°C).

Installation and

Service Manual

39

Remember, no water heating system provides exact
temperatures at all times. Let the system operate a few days at
your desired settings to determine correct settings for your
needs.

1. These units are equipped with an operating temperature
control.

2. The control set points are preset to a low test setting when
shipped from the factory.

3. Reset the temperature set points to the lowest settings
which will satisfy hot water demands, eliminate a possible
condensate problem and prevent a risk of scald injury.

 WARNING: Return water temperatures

must not be less than 140°F (60°C). If lower
return wate temperatures are required, folllow
the instructions for Low Temperature Return
Water Systems, page 25.

4. The High-Fire Offset should normally be adjusted to “0”
when supplying potable hot water for domestic use.

5. Stage firing can be achieved by adjusting the High-Fire
Offset to any value other than zero. Typically, a setting of
3°F is 5°F is suitable for stage firing in a water heater
application. Stage firing of a potable water heater is
normally only used to replace system standby heat loss.

6. All stages of burner operation should fire when there is a
major draw from the potable hot water storage system.
This prevents possible condensate problems and ensures a
rapid recovery of the hot water used.

Note: The High-Fire stage will be delayed by approximately
10 seconds to allow a soft start of the water heater.

IMPORTANT: When water is stored at
temperatures above 125°F (52°C), a thermostatic
mixing valve must be installed on the hot water
outlet from the storage tank to supply lower
temperature water and prevent the risk of a scald
injury.

Note: This water heater, when set at a lower temperature
setting, is not capable of producing hot water of sufficient
temperature for sanitizing purposes.

Location of Cold Water Supply Piping
Connections

Incorrect piping of the cold water supply to the system may
result in excessive low temperature operation causing
condensate formation on the heat exchanger and operational
problems. You must install the cold water supply piping in the
discharge piping from the heater to the storage tank. This
allows the cold water to be tempered in the storage tank before
entering the heater. See Figure 41 and typical installation
drawings provided with the unit for correct piping. Higher
water temperatures reduce condensate formation.

 WARNING: Should overheating occur or

the gas supply fail to shut off, do not turn off or
disconnect the electrical supply to the pump.
Instead, shut off the gas supply at a location
external to the unit.

High Water Temperature Limit Control

The unit is equipped with an adjustable setting, auto-reset high
water temperature limit control. The hot water heater
temperature limit control has a maximum limit setting of
200°F (93°C). If water temperature exceeds the set point, the
limit will break the control circuit and shut down the unit. The
limit control will only be reset after the water temperature has
cooled below the set point of the limit. The high water
temperature limit control is mounted in the outlet side of the
front header. A manual reset high water temperature limit
control is available as an optional control.

Optional Relief Valve

This water heater is normally supplied with a temperature and
pressure relief valve(s) sized in accordance with applicable
codes. Units may be supplied with an optional pressure only
relief valve(s). When a water heater equipped with this
optional relief valve is piped to a separate storage vessel, the
storage vessel MUST have a properly installed temperature
and pressure relief valve which complies with local codes.

Thermal Expansion

A relief valve which discharges periodically may be due to
thermal expansion in a closed system. A hot water supply
boiler installed in a closed system, such as one with a backflow
preventer or check valve installed in the cold water supply,
shall be provided with means to control expansion. Contact the
water supplier or local plumbing inspector on how to correct
this situation. Do not plug or cap the relief valve discharge!

Cathodic Protection

Hydrogen gas, which is extremely flammable, can be produced
in a hot water system that has been unused for a long period of
time (generally two weeks or more). To prevent the possibility
of injury under these conditions, open the kitchen sink hot
water faucet for several minutes before using any electrical
appliance connected to the hot water system. If hydrogen is
present, there will be an unusual sound such as air escaping
through the pipe as the hot water begins to flow. Do not smoke
or have open flames near the faucet at this time.

CLEANING AND
MAINTENANCE

Listed below are items that must be checked to ensure safe
reliable operations. Verify proper operation after servicing.

 CAUTION: Label all wires prior to

disconnection when servicing controls. Wiring
errors can cause improper and dangerous
operation.

Appliance Area

Keep appliance area clear and free from combustible materials,
gasoline and other flammable vapors and liquids.

Water Circulating Pump

Inspect pump every six months and oil as necessary. Use SAE
30 non-detergent oil or lubricant specified by pump
manufacturer.

Burner Flames

Visually check main burner flames at each start up after long
shutdown periods or at least every six months. Burner
viewports are located on the right and left sides of the unit.

Figure 43 - Flame Pattern Illustration

 WARNING: The areas around the burner

viewports are hot. Direct contact with unit could
result in burns.

Normal Flame: A normal flame is blue with slight yellow tips,
has a well-defined inner cone, and displays no lifting flames.

Yellow Tips: The usual causes for yellow tips on the burner
flame are burner air flow blockage or partial obstruction.

Yellow Flames: The usual causes for yellow flames are
primary air flow blockage to the burner(s) or excessive gas
input. Correct this condition immediately.

Lifting Flames: The usual causes for lifting flames are over
firing the burner(s), excessive primary air, or high draft.

If you observe improper flame patterns, examine the venting
system, ensure proper gas supply, and ensure adequate supply
of combustion and ventilation air.

Flue Gas Passageways Cleaning
Procedures

Any sign of soot around the outer jacket, at the burners or in
the areas between the fins on the copper heat exchanger
indicates a need for cleaning. The following cleaning
procedures must only be performed by a qualified serviceman
or installer. Proper service is required to maintain safe
operation. Properly installed and adjusted units seldom need
flue cleaning.

IMPORTANT: All gaskets on disassembled
components must be replaced with new gaskets
on reassembly. Gasket kits are available from
your distributor.

Burner Removal and Cleaning

1. Turn off main power to unit.

2. Turn off main manual gas shutoff to unit.

3. Remove the front outer jacket panels.

4. Disconnect manifold from gas train using union(s) just
below each gas valve(s).

5. Remove mounting screws from manifold mounting
brackets. Pull the manifold/orifice assembly away from
burners. Repeat for each manifold assembly.

6. Remove two mounting screws from burner and slide
burner out toward front of unit. Use caution to prevent
damage to burners, refractory, hot surface igniter or wiring.

7. Remove soot from burners with a stiff bristle brush. Dirt
may be removed from burner ports by rinsing the burner
thoroughly with water. Drain and dry burners before re­installing. Damaged burners must be replaced.

When installed in a dusty and dirty location, the burners may
require cleaning on a 3 to 6 month schedule or as needed,
based on severity of contamination. Contaminants can be
drawn in with the combustion air. Non combustible particulate
matter such as dust, dirt, concrete dust or dry wall dust can
block burner ports and cause non-warrantable failure. The
standard inlet air filter will help eliminate dust and dirt from
entering the unit. Use extreme care when operating a unit for
temporary heat during new construction. The burners could
require a thorough cleaning before the unit is placed in service.

Hydronic Heating Boilers and
Domestic Water Heaters

40

Installation and

Service Manual

41

Heat Exchanger Cleaning

1. While burners are removed, check the heat exchanger
surface for sooting. If present, heat exchanger must be
cleaned and problem corrected. Proceed as follows.

2. Remove gas manifold(s)/orifice assemblies as described in
steps 1 through 5 in Burner Removal and Cleaning, page

40.

3. Disconnect wiring from the hot surface igniter and hose
from the burner pressure tap.

4. Remove inner jacket panel mounting screws and slide door
assembly out toward front of the unit. Use caution to
prevent damage to the refractory and hot surface igniter.

5. Check "V" baffles and frame runners along front and back
edges of heat exchanger. Remove and clean if necessary.

6. Remove soot from heat exchanger with a stiff bristle brush.
Use a vacuum to remove loose soot from surfaces and
inner chamber.

7. The heat exchanger can be removed by sliding towards the
front of the unit. Once the heat exchanger is removed from
the unit, a garden hose can be used to wash the tubes to
ensure that all soot is removed from the heat exchanger
surfaces. Note: Do not wet the unit's refractory.

8. Ensure that all burner ports are cleaned to remove any soot.
See Burner Removal and Cleaning, page 40.

9. Carefully reinstall the heat exchanger, "V" baffles, and
frame runners if removed from the unit. Note: Make sure
frame runners seal securely where they contact the front
and rear compartment refractory.

10. Carefully reinstall inner jacket panels, burners, manifolds,
wires and hoses. Use new gasket material to ensure a
proper air seal.

11. Reassemble all gas and water piping. Test for gas leaks.

12. Reassemble outer jacket panels.

13. Cycle unit and check for proper operation.

Electrical

This unit uses a transformer to supply a low voltage control
circuit. The voltage on the secondary side should be 24 to
28VAC when measured with a volt meter. Larger models have
a 7AMP circuit breaker provided on the secondary side of the
transformer. A tripped circuit breaker indicates a short in the
24VAC controls that must be corrected.

Combustion and Ventilation Air

Combustion Air Filter (Models 985,000 ­2,065,000 Btu/hr Only)

This unit has a standard air filter(s) located behind the
combustion air inlet panel(s). This filter helps ensure clean air
is used for the combustion process. Check this filter every
month and replace when it becomes dirty. The filter size is
12" x 16" x 1" (30.5cm x 40.6cm x 2.5cm). You can find this
commercially available filter at any home center or HVAC
supply store.

To install filter, see Combustion Air Filter, page 8.

Air Flow

Check frequently to be sure the flow of combustion and
ventilation air to the unit is not obstructed.

Combustion Air Fan

These units use a fan-assisted combustion process. These units
have one fan to supply combustion air to the burners.

Fan Cleaning

Check each combustion air fan every six months. Clean fan as
required when installed in a dusty or dirty location. Oiling is
not required.

Combustion Air Fan Adjustment

The combustion air fan is factory preset and should not need
adjustment in most cases. Follow the steps below to adjust the
fan if a continuous Low Air Status Code occurs.

Check for proper installation and draft in the venting system.
Correct as required.

Adjusting Differential Air Pressure

The following is a recommended method for setting the
differential air pressure (P) for the fan.

CLEANING AND
MAINTENANCE

CONTINUED

Figure 43 - Air Pressure Switch

Figure 44 - Adjusting Air Shutter

Set Up Procedure

To the left of the fan is an air pressure switch with a large and
a small tube delivering pressure from points inside the unit (see
Figure 43). The pressure in the large tube is the chamber
pressure. The pressure in the small tube is the burner pressure.
They act together to make the pressure switch. By
disconnecting the caps from the tees in the pressure switch
hoses and connecting them to either side of a manometer, you
can read the differential pressure to the switch.

The " (+)" connection on the manometer connects to the tee in
the tubing from the units front chamber and the " (-) "
connection on the manometer connects to the tee in the small
tubing from the burner.

Upon a call for heat, the fan will run for about 90 seconds
before going into soft lockout. If necessary, turn the power to
the unit OFF and then back ON again to recycle the fan.

Note: If the unit has been firing recently, allow the unit to cool
for five minutes with the fan running before beginning the
adjustment procedure.

Note: Retain the plastic caps removed from the tees for
reinstallation when complete.

Figure 45 - Combustion Air Adjustment with a Manometer
to set Differential Pressures

Adjustment Procedure: 495,000 - 1,255,000 Btu/hr
Models

1. Remove the upper front jacket panels from the unit to
access the upper chamber.

2. Locate the air shutter on the side of the fan housing (see
Figure 44). Turn the adjustment screw on the air shutter to
open or close the shutter. Increase air shutter opening to
increase air pressure. Decrease air shutter opening to
decrease air pressure.

3. Adjust the air shutter until the differential pressure is
nominally 1.2 - 1.35 inches water column for models
495,000 - 745,000 Btu/hr and 1.1 - 1.3 inches water
column for models 985,000 - 1,255,000 Btu/hr. Note: The

air chamber pressure is 1.2 inches water column for
liquefied petroleum (L.P.) and 1.4 inches water column
for natural. See Figure 45 on installations up to 2000 feet

altitude. Contact the factory for high altitude pressure
settings.

4. Once the adjustment procedure is complete, reconnect the
caps to the tees in the hoses to the pressure switches and
check all tubing and wire connections for a snug fit. Test
fire the unit. Reinstall upper panels.

Hydronic Heating Boilers and
Domestic Water Heaters

42

4

3

2

1

0

1

2

3

4

Turn the adjustment screw on
the air shutter to open or close
shutter.

Installation and

Service Manual

43

Adjustment Procedure: 1,435,000, 1,795,000 and
2,065,000 Btu/hr Models

1. Remove the upper front jacket panels from the unit to
access the upper chamber.

2. Slightly loosen the screws that attach the fan transition box
to the metal base (see Figure 46).

3. Locate the air shutter at the rear of the fan duct (see
Figure 47). Move the air shutter towards the rear of the unit
to increase air pressure. Move the air shutter towards the
front of the unit to decrease air pressure.

4. Adjust the air shutter until the differential pressure is
nominally 1.1 - 1.3 inches water column. Note: The air

chamber pressure is 1.2 inches water column for
liquefied petroleum (L.P.) and 1.4 inches water column
for natural. See Figure 45 for installations up to 2000 feet

altitude. Contact the factory for high altitude settings.

5. Once the adjustment procedure is complete, reattach the
caps to the tees in the hoses to the pressure switch and
check all tubing and wire connections for a snug fit. Test
fire the unit. Reinstall upper panels.

Figure 46 - Loosening the Transition Box Screws,
1,435,000, 1,795,000 and 2,065,000 Btu/hr Models Only

Figure 47 - Adjusting Air Shutter

Servicing Hot Surface Igniter and
Ignition Module

This unit uses a proven hot surface ignition module and a hot
surface igniter. The hot surface ignition module is not
repairable. Any modification or repairs will invalidate the
warranty.

 WARNING: Do not attempt to repair a faulty

hot surface igniter or ignition module. Any
modification or repairs may create hazardous
conditions that result in property damage,
personal injury, fire, explosion and/or toxic gases.

CLEANING AND
MAINTENANCE

CONTINUED

A faulty hot surface igniter or ignition module must be
replaced with an identical part. A specification igniter and
ignition module for this specific unit is available from your
local distributor. Do not use general purpose field

replacement ignition modules or igniters.

Ignition System Checkout

1. Turn off gas supply to unit.

2. Turn electric power on.

3. Adjust the set point on the temperature control to a setting
above water temperature or to the highest safe setting.

4. The igniter will cycle on trial for ignition.

5. The ignition module will lock out and turn the alarm light on.

6. Adjust the Set Point Differential and High-Fire Offset to the
desired settings.

7. Turn on gas supply.

8. Press the module reset button to reset the ignition module.
This is a red button beside the ignition module or on the
diagnostic panel on the header-end of the unit.

9. If ignition system fails to operate properly, repair work must
be performed by a qualified service person or installer.

SEQUENCE OF OPERATION

OVERVIEW

This sequence of operation can be considered the order of
events in sequential order that occur after the appliance has
received a call for heat. The process begins with 120VAC
power entering the appliance and ends with the appliance
going into an idle state after completion of a successful call for
heat.

Note: The following descriptions do not include remotely
connected devices that may be connected to the appliance.
Refer to the wiring diagram for actual point to point wiring
connections that show power delivery.

1. The POWER switch is placed in the “ON” position.

2. 120VAC power is supplied to the control transformer

along with L1 and F1 on the ignition module.

3. 24VAC is supplied to the electronic temperature control,

the ignition module and the adjustable high limit control.

4. 24VAC is then supplied to the auxiliary limit control (if

equipped).

5. If equipped, 24VAC is supplied to a low water cut-off and

then to the high and low gas pressure switches.

6. 24VAC is supplied to the continuous alarm terminals A1

and A2 and then to the remote stage one terminal strip, 1C
and 1NO.

7. 24VAC is supplied to the electronic temperature control.

8. The electronic temperature control then calls for heat.

9. 24VAC is supplied to the intermittent alarm field safety
contacts, B1 and B2.

10. 24VAC is supplied to the water flow switch (if equipped).

11. 24VAC is supplied to the TH terminals on the ignition
module.

12. As power is applied to the TH terminals on the ignition
module, 120VAC is switched from the F2 terminal to start
the combustion air fan at full speed on the 495,000 ­745,000 Btu/hr models and at low speed on the 985,000 ­2,065,000 Btu/hr models.

13. 24VAC is supplied to the C terminal of the air pressure
switch. As the low air switch makes, power is supplied to
the ignition module.

14. 24VAC is then supplied to the PS terminals on the ignition
module as the air pressure switch makes to prove fan
operation..

15. The combustion air fan operates for the pre-purge period.

16. At the end of the pre-purge, 120VAC is applied to the hot
surface igniter and the trial for ignition light.

17. The hot surface igniter proves 1800 F (982 C) ignition
temperature by current draw through the ignition module.

18. The ignition module supplies voltage to the MV terminals
on to the gas valve(s).

F9 SINGLE STAGE FIRING

19. All gas valves on the 495,000 - 745,000 Btu/hr models and
approximately half of the valves on the 985,000 ­2,065,000 Btu/hr models open, supplying gas to the orifice
and burner inlet to pre-mix.

20. The gas/air mixture is forced into the burner and out of the
burner ports under pressure.

21. The hot surface igniter lights the gas/air mixture and then
serves as a flame sensor to prove main burner flame by
rectification.

22. After a time delay of 10 seconds, the remaining gas valves
on the 985,000 - 2,065,000 Btu/hr models open, supplying
gas to the remaining burners.

23. The gas/air mixture is forced out of the burners and out of
the burner ports under pressure.

24. The burners light by carryover from the burners currently
firing.

25. The heater is now firing at full rated input.

M9 MODULE FIRING

26. The first stage gas valve(s) opens and supplies gas to the

orifice and burner inlet to pre-mix.

27. The gas/air mixture is forced into the burner and out of the

burner ports under pressure.

28. The hot surface igniter lights the gas/air mixture and then

serves as a flame sensor to prove main burner flame by
rectification.

Hydronic Heating Boilers and
Domestic Water Heaters

44

29. Burners are now firing for approximately 50% of the
heater’s input.

30. 24VAC is supplied from the second stage of the electronic
temperature control across the 2C and 2NO terminals on
the terminal strip on to a control to a relay.

31. The control relay switches the fan on the 985,000 ­2,065,000 Btu/hr models to high speed and energizes the
gas valves for the remaining 50% of burner input.

32. The remaining gas valves open and supply gas to the
orifice inlet to pre-mix.

33. The gas/air mixture is forced out of the burner ports and
light by carryover from the burners currently firing.

34. The heater is now firing at full rated input.

HEAT TRANSFER PROCESS

35. Heated products of combustion pass over the heat
exchanger transferring heat to the water.

36. The rate of flue product movement is controlled by “V”
baffles on the heat exchanger to maximize heat transfer.

37. Flue products pass into the flue collector and are
exhausted from the unit.

END OF SEQUENCE

38. Set point for the high fire on the electronic temperature

control is satisfied.

39. Power to all valves is turned OFF on F9 systems and

power to the high fire gas valves is turned OFF on M9
systems.

40. The water temperature continues to rise and the set point

for low fire is satisfied (M9).

41. Power to the low fire gas valves is turned OFF (M9).

42. The combustion air fan runs for a 30 second post purge

timing and turns OFF.

43. The appliance is now in a Standby Mode waiting for the

next “call for heat”.

GLOSSARY

Power Supply

(AC120VAC/60Hz)

120VAC/60Hz/1PH power connects to black (line) and white
(neutral) wires located within an electrical wiring box located
on the left side of the unit. A green chassis grounding wire is
also provided for connection to earth ground.

ON/OFF Rocker Switch

The black line voltage wire runs directly to a single pole, single
throw On/Off rocker switch located behind the front cover
accessible by a thumb screw. Turning ON the rocker switch
delivers line voltage to the low voltage transformer and
ignition module.

Note: The On/Off switch does not provide for disconnection of
power being supplied to any remotely connected devices that
may be connected to the unit (i.e. pumps, louvers, power

venters, etc.,). As such, it may be necessary to locate and turn
off power to these items before attempting to service the unit.

Low Voltage Supply Transformer

A 120VAC to 24VAC transformer located within the control
panel provides 24VAC/60Hz to many of the components
located on the unit. One of its 24VAC outputs (blue) is
connected to a circuit breaker and the other (yellow) is
connected to chassis ground.

24VAC Circuit Breaker

A circuit breaker is provided on the 985,000 - 2,065,000 Btu/hr
models for protection of the low voltage supply transformer
from overloads and short circuits. The breaker is located inside
the unit on the lower right corner of the control panel. Power
from this breaker goes to the electronic temperature controller,
ignition module and various other components and/or options
on the unit. When tripped, all factory-installed 24VAC
components will lose their 24VAC power.

Manual Reset High-Limit Thermostat

A manual reset high limit thermostat is provided as backup for
the temperature controller. This will either be an adjustable dial
or fixed temperature bulb-capillary style thermostat that will
trip and require resetting should water temperature exceed its
settings. When tripped, all controls remain powered, but
24VAC is prevented from being delivered to the ignition
module's thermostat input.

EMS/Sequencer/Remote Aquastat
Terminals

The EMS/sequencer/remote aquastat terminals are provided
for connection of the unit to an external energy management
system or sequencer and are located along the top edge of the
terminal strip located within the electrical wiring box. In
addition to providing a means to externally stage fire the unit,
these terminals also provide for remote shutdown and override
by routing through dry contacts from external devices.
Connection of the external dry contacts to these terminals
requires the removal of one or more factory installed jumpers
located on the terminal strip.

Safety Device Terminals

The safety device terminals ensure that no power can be
delivered to the ignition module unless factory/field-installed
safety devices such as flow switches and gas pressure switches
are closed. These safety device terminals are located below the
EMS/Sequencer/Remote Aquastat terminals located within the
electrical wiring box. Two types of connections are offered:
Continuous terminals provide for connection of safety devices
that are desired to be constantly monitored. Intermittent
terminals are provided for devices that are only monitored
during a "call for heat" cycle. Connection to either of these
terminals requires the removal of a factory-installed jumper
located on the terminal strip.

Installation and

Service Manual

45

Electronic Temperature Controller

(Operator)

A 2-stage electronic temperature controller is provided on the
unit and it serves to maintain a user selectable temperature set
point. Ultimately, the temperature controller delivers 24VAC to
the ignition module and pressure switch when it senses heat
mode is desired. It also activates the pump relay. If more heat is
needed, it activates the high fire stage.

Ignition Module

(Controlled by Electronic Temperature Controller)

One ignition module is provided on the unit. Upon sensing the
24VAC delivered to it by the electronic temperature controller,
the ignition module checks for a shorted pressure switch and
then, provided the air switch isn't shorted, supplies 120VAC to
its blower output relay and waits for a pressure switch signal.

Two Speed Blower (Controlled by Ignition

Module and Relay Board)

A single 2-speed blower on the 985,000 - 2,065,000 Btu/hr
models (single 1-speed blower on the 495,000 - 745,000 Btu/hr
models) provide combustion air to the unit. The blower is
provided with a high and low speed tap. The blower operates
in tandem with the ignition module when a call for heat signal
is received. Depending upon the number of stages in operation,
the blower's speed may increase or decrease accordingly.

Pressure Switch (Activated by Blower Turning

On)

One pressure switch is provided to monitor the blower On/Off
operation. Upon a call for heat, 24VAC is delivered to the
pressure switch. If the blower generates adequate air pressure,
the pressure switch closes to deliver 24VAC to the ignition
module pressure switch monitoring input terminal.

Prepurge (Ignition Module Function)

Once the ignition module sees a 24VAC input from the
pressure switch, it runs the blower for approximately 15
seconds in order to purge the combustion chamber of any
unburned fuel/air mixture.

Trial for Ignition (Ignition Module Function)

Once the ignition module has completed its prepurge period, it
turns on the hot surface igniter. Once the hot surface igniter's
current draw reaches a proper level, the ignition module begins
a trial for ignition period of approximately 25 seconds to allow
time for the igniter to reach the ignition temperature necessary
to ignite the fuel/air mixture.

Igniter (Controlled by Ignition Module)

One igniter is provided in order to ignite the fuel/air mixture
and its on/off operation is controlled by the ignition module.

Relay Board (Controlled by Electronic

Temperature Controller and Ignition Module)

A small relay board is provided on the 985,000 - 2,065,000
Btu/hr models to switch the blower from low to high speed and
to deliver power from the low fire stage (Stage 1) to the high
fire stage (Stage 2) depending upon the electronic thermostat's
settings.

Ignition (Ignition Module Function)

Once the trial for ignition period has been completed, the
ignition module sends 24VAC to the gas valves on the low fire
stage (Stage 1). Gas valves should open and allow gas to flow
to the burners in Stage 1 being energized. The fuel/air mixture
should ignite from the hot surface igniter. Once this voltage has
been sent to the valves, the hot surface igniter is turned off. The
ignition module then monitors the status of the flame and will
either allow ignition to continue or shut down the gas valves
should flame not be proven and proceed to a Flame Failure
condition. If flame was proven briefly during the ignition
period, the module may not proceed to Flame Failure, but
rather post-purge and then go into another trial for ignition.

Heat Transfer Process (Gas Valves, Burner,

and Heat Exchanger)

Once flame has been proven, the ignition module will hold the
gas valves open as long as there is proof of flame and a call for
heat is present. If the low fire stage cannot provide enough heat
to raise the system temperature, the electronic temperature
controller turns on the high fire stage. The high fire stage will
operate until the system water temperature shows a gain that
can be handled by low fire operation. The high fire stage shuts
off at this point. When the low-fire stage alone produces more
heat than is required, the electronic temperature controller
turns off the call for heat.

Post-Purge (Ignition Module Function)

When 24VAC is removed from the ignition module's
thermostat input, the module turns off the gas valves and
maintains the blower for approximately 25 seconds in order to
allow the combustion chamber to be purged of all combustion
by-products.

Pump Delay (Electronic Thermostat Function)

When the electronic thermostat removes 24VAC from the
ignition module, it continues to hold the pump relay on for 30
seconds in order to get the remaining heat out of the
combustion chamber. The pump then turns off to prevent the
heat in the water from going back into the combustion chamber
and up the flue.

Idle (Electronic Thermostat Function)

After completion of the post-purge cycle, the unit will go into
an idle state whereby the electronic thermostat continuously
monitors the water temperature until the water temperature
drops to levels that require additional heat.

Hydronic Heating Boilers and
Domestic Water Heaters

46

47

SCHEMATIC DIAGRAM

MODELS 495,000 - 745,000 BTU/HR

W

W

BR

ACC.

PLUG

W

YR

G

PV/MV

Y

Y

PV/MV

Y

W

W

BR

BR

VENT VALVE

NORMALLY OPEN

SHUTOFF/

SOLENOID

F1

BK

+

-

FLAME

CURRENT

TEST PIN S

OPEN

C

LOUVER

NC

HiGas

C

NO

LoGas

C

NO

BR

F2

LINE

S1

412

5

GY

GY

G

BUR NER GROU ND

XB

C

BLOWER

LOW FIRE VALVE

FLASH

CODE LED

NOT

USED

NEU

S2/FS

GY

TRIAL

GY/W

IGNITER

Y

IND.

LOW AIR

PU

LOW AIR

O

G

24COM

TH

RESET

24VAC

9

8

7

6

10

O

BL/W

Y

BL

FLAME FAILUR E RESET

BL

T

O.A.

O/W

O/W

Y

O

R

COM

FIELD

OPTIONS

FLOW SWITC H

INTERMI TTENT

DISCONNECT POWER BEFORE SERVICING THE UNIT

Neutral

FIELD PROVIDED

REMOTE OPER ATOR

NO

BK

W

COM

CONTINUOUS

W

W

BL

W

3

BK/W

BK

G

1

2

POWER SWITCH

BK

GROUN D

CHASSIS

120VAC/60HZ

Line

Groun d

NC

OPTION AL

AUX. LIMIT

COM

R

NC

HI-LIMIT

COM

O

BL

Y

24VCOM

Y

24 GND

R/O

BL

DC 24V COIL

PUMP RELAY

FLOW

24VAC

120

O

R1 W1

BL

SWITCH

VAC

PV

RMV

IGNITION

5PS4FF1

T

SENSOR

BK

CN3

INLET

2

CN1

CN8

CN7

O

O

PU

PUMP

OPTION AL

HEATING

MV

R

MODULE

PV

MV

HIGH FIRE VALVE

R

R/O

R

HI-LOW FIRE

FULL-FIRE STANDARD

PU/W

R2 W2

FLAME FAILURE

FIELD PROVIDED

O

REMOTE OPERATOR

INLE T

R

SENSOR

R/O

BK

PROBE

1

ENABLE

SENSOR

ON

NO

ON BOI LER

PR

CN5

CN4

CN2

DISABLE

SHUTDOWN

O.A.

O.A. MAX. RATIO

SHUTDOWN

241

3

Y

BL

C

BK

W

SYS/

TAN K

I/O RESET

OPTIONAL

T=TAN

W = WHITE

ITEM INDICATES

PR

CN1

Y=YELL OW

BK = BLACK

JUNCTION POINT

R/O R/O

SENSOR

SYSTEM/TANK

CN9

CN6

OFFSET

HIGH-FIRE

DIFFERENTIAL

OPERATOR

SETPOINT

OFF

R=RED

BR=BROWN

G=GREEN

GY=GR AY

O=ORAN GE

PR=PURPLE

BL=BLUE

P=PINK

EQUIPM ENT

DOTTED LINE

CLOSED END SPLIC E

INDI CATES OPTION AL

(ELECTRICALLY SAME)

W

120VAC

POWER

BK

BK

W

NO

L

C

BR

BK

120V NEUTRAL

IGNITION

MODULE

"F2"

24VAC ALARM

OPTION AL

W

SILENCE

OPTIONAL ALARM ON ANY FAILURE

G

Y

24V COM

O

OPERATOR CN1 (4)

PROBE

T

T

TEST SWITCH

O.C.

J1

J2

321

RESET

P

GND

PR

G

RESET

PR

PR

OPTION AL

WITH ALA RM

BL

LWCO OR LW CO

BK

"B"

BELL

BR

BR

CNOC

T

IGN MODULE PIN 5 (MV)

24V C OM

BL

J3

6

1

2

54

3

J4

O

MF

O

DAMPER

TO LOUVER OR

LBL20034 REV A

CLOSED

OPEN

C

"X"

OPTION BOX "A", "B" OR "C"

"FIELD PROVIDED LOUVER PROVING SWITCH"

VENTE R CONTA CTS

SCHEMATIC/LADDER DIAGRAM

OPTIONAL LOUVER-

ALARM

CONTACTS

R

R

OPTION BOX "C" ONLY

BR

BR

O/W

NO

TD

Y

Y

NC

R

C

R

O

LWCO

ALARM

24V C OM

CONTACTS

R

R

Y

24V COM

BR

BR

Y

NO

R

C

BR/W

PR

P

LWC O IND.

"C"

"R1"

OPTION BOX "B" OR "C"

48

WIRING DIAGRAMS - MAIN UNIT CONNECTIONS
MODELS 495,000 - 745,000 BTU/HR

POWER

SWITCH

120 VAC

TRIAL

24 VAC

HEATING

24VAC FLAME

FAILURE

BK

W

GY

GY

O

Y

BL

PR

HI-L IMIT

C

N

O

N

C

C

2

1

AUX

HI-LIMIT

OPTIONA L

CN

O

N

C

C21

14

5

9

10

12 15

36

8

7

13

BK/W

11

BK

O

R

R

BK

INLET

SENSOR

H

HI-LIMITS - PWR SW

JUMPERED IF

NOT PROVIDED

DISCONNECT POWER BEFORE SERVICING THE UNIT

T

=

TAN

Y

=

Y

E

LLOW

B

R

=B

R

O

WN

G

=

G

R

EEN

GY=GR

A

Y

R

=

R

E

D

W

=

W

H

ITE

B

K

=

B

L

ACK

PR=PU

R

P

LE

B

L

=BLUE

P

=

P

I

NK

O=OR

A

N

G

E

x

MATING
BLOCKS

SPLICE

SPLICE

LOW GAS

HIGH GAS

N

O

C

O

MNC

O

P

TIO

N

AL HIG

H

-LO

W

G

A

S PRESSURE

N

O

C

O

MNC

BL

BL

PR

24VAC COM

OPT. REM OTE

THERMOSTA TS

O

N

/OFF (HIGH

F

IRE)

(LOW F IRE)

OPTIONAL

FLOW

SWITCH

X & B =
INTERMITTENT PU MP

CONNE CT TO:

R1 - W1 =
CONTINUOUS PUMP

COM

NC
NO

WHEN REPLACING DAMAGED WIRING, USE EQUIVALENT TYPE AND GAUGE.

D

O

TTED LIN

E

S IND

I

C

A

T

E

OPTI ON

A

L

EQU

I

PMENT

U

N

L

ESS OTH

E

R

W

ISE

IN

D

I

C

A

T

ED

W

BR

W

BR

1

2

SHUTOFF
VALVE

NORMALLY
OPEN VE NT
VALVE

OPTIONAL

SHUTOFF/ NORMALLY OPEN

VENT VA LVE

120VAC

120VAC

GAS TRAIN

R1 W1 R2 W2 A X B C

STAGE 1

STAG E 2

LIMITS

14

5

36

1

2

4

5

9

10

11

12

14

15

36

8

713

45

9

1012

15

3

6

87

13

1

O

R/O

R/O

O/W

PR

11

SPLICE

1

2

W

BR

O/W

PR

Y

OPTIONA L

SYSTEM/

TANK

SENSOR

Y

R/O

BK

BK

BK/W

GY

GY

Y

W

H

D

ACCS.
PLUG

G

TERMINAL STRIP - SENSOR

O

P

STA

N

D

A

RD

BL

O

O

P

T. BOX.

O

P

T. BOX.

NOT USED

PR

O

14

5

36

24V

DC

1

2

9

10

11

123

8

7

1

2

12

4

3

6

87

SPLICE 10

14

5

10

11

12

14

36

7

13

SPLICE 1

PUMP DELAY RELAY

"24VDC"COIL

D

E

F

A

B

BK/W

BK

O

O

SPLICE 9

G

24C OM

GND

CONTROL PANE

SPLICE

3

C

OPTION B OX CONN ECTOR

PIN

S

1 &

2
JUMPERED
P

R

OVIDE

D

IF N

O

O

P

TIO

N

S
A

R

E

OR

D

E

R

E

D

SPLICE 4

SPLICE 2

SPLICE 7

S2/FS

F1

F2

LINE

S1

NEU

5

4

1

2

3

GY/W

TH

10

PI

9
8

24COM

NOT

USED

O

P

BK

W

G

1

2

4

5

7

10

11

12

14

13

3

6

BR

GY

PR/W

IGNITION

MODULE

RESET

7

24VAC

6
5

PS

4
3

M/S

2

FF

1

T

BL/W

PR/W

MV

BL/W

BL

R

B

BL

FLAME FAIL RESET

IGNITION MODULE

SPLICE

BK

BL

P

R

9

LOUVER

NOCOM NC

T

BL

5

R

E

SET

N

O

R

M

ALLY

C

L

OSED

P

R

8

24 VAC

CON

T

R

O

L

J

3

5

4

6

1

2

3

O.C.

J1

J2
3

2

1

J4

P

GND

GND

P

R

BL

BL

Y

Y

Y

Y

P

R

G

G

O

P

P

PR

TIME

DELAY

1

2

3

4

BR

6

Y

SPLICE

7

O

W

R

T

Y

G

T

OPTION BOX "C"

O/W

T

T

BR

BR

O

B

R

N

O

C

C

T

NO

NO C

Y

C

BR/W

O

P

O

49

WIRING DIAGRAMS - MAIN UNIT CONNECTIONS
MODELS 495,000 - 745,000 BTU/HR (CONTINUED)

SPLICE

4

10

13

111214

15

124

5

36

713

10

8

111214

9

15

CHASSIS GROUND

1

E

BK

W

2

SPLICE

G

BK

W

W

BK

120VAC
SUPPLY

W

BK

120VA
C
PUMP

SPLICE

G

2

1

F

9

111214

8

713

10

GY

Y

153

Y

R/O

R

GY

SPLICE

O

T

MVPVMV/PV

G

SPLICE 5

Y

BL

SPLICE 8

SPLICE 9

SPLICE 6

24 VAC

MAIN UNIT - GAS VALVES - BLOWER PRESSURE SWITCH

CN7
CN8

124

5

36

7

10

8

11

9

12

BK

LOW VOLTAGE

XFMR.

4

3

2

1

CN1

OFF

NEL

TEST

NORMALLY

CLOSED

O/W

NO

CNOC C

PR

PR

Y

`

LOU VER /D AM PER

120 VAC RELAY

6

2

4

NC

BR

O

W

SPLICE

BK
BK

T

BR/W

1

BR

G

BR

O

3

6

5

4

978

PR

P

1

2

BR

BR

3

5

6

PR

LWCO INDICATOR

1

2

ALARM BELLSILEN CE

1

4

798

BURNER

GROUND

O BK

O

BL

R/O

OA SENSOR

O

OPERATOR

SHUTDOWN

O.A. MAX. RATIO

OPTIONAL

SETPOINT

OPERATOR

LWCO

PROBE

T

W

CONTACTS

R
R

O

P

Y

HOT SURFACE IGNITER

36

Y

124

CN1

SENSOR

ON

ENABLE

DISABLE

SHUTDOWN

O.A.

I/O RE S ET

O BL

120VAC
POWER

DAMPER

W

HIGH-FIRE

OFF SET

RESET

DIFFERENTIAL

~~~~

~~~~

FOR

ALARM

"R1"

"C"

BK

BK

TO LOUVER OR

VALVE #1

12

9

11

5

8

10

7

A

RO

CN3

2

INLET

PROBE

1

CN4

CN2

CN5

CN9

TO

CN9

PR

PR

O.C.

J1

24 VA C

CONTROL

J2

21

3

J4

P GND

LWCO
ALARM
CONTACTS
24 VAC
RELAY

G

BR/W

6

G

2

G

4

BR

OPTION B OX " B"

SYS/

TANK

CN6

O

LOU VER /D AM PER

WIRING CONNECTIONS DIAGRAM

Y

HI-LOW FIRE

FULL FIRE

PR

IND ICA TOR

COM

AIR PRESSURE

SWITCH

BK

PR

PR

BL

TEST

T

J3

Y

3

5

2

461

BR/W

P

O

P

BR/W

120 VAC RELAY

6

BK

2

BK

4

BR

Y

LOW AIR

MVPVMV/PV

VALVE #2

3

4

W

2

BR

1

6

2

4

LOUVER/DAMPER

120 VAC RELAY

OPTION BOX "A"

3

W

4

2

5

1

6

9

G

BL

BR

Y

SPLICE

BR/W

BR/W

T

1

BR

G

BR

O

P

1

2

5

4

78

1

BK

2

BK

3

6

TO LOUVER OR

LBL20007 REV A

BLOWER

BR

BK
BK

SILENCE

BR

3

6

120VAC
POWER

DAMPER

GROU ND

1

2

TO LOUVER OR

C

ALARM BELL

~~~~
~~~~

LWCO

PROBE

T

1

5784

W

"R1 "

W

1

2

C

DAMPER

W

O

P

120VAC
POWER

BK

BK

CONTACTS

LWCO ALARM

R

O

BL

GR

W

FOR

R

50

SCHEMATIC AND WIRING DIAGRAM
MODELS 985,000 - 2,065,000 BTU/HR

Y

YR

YR

.

, REFER TO ACTU AL COMPONENTS FOR EXA CT TERMINAL LOCATION S.

STRIP REQU IRE THE REMOVA L OF SOME OF THE SHORTING B ARS FROM THE TER MINAL STRIP

(3) SCHEMATIC IS WIRING DIAGRAM

(4) WHEN REPLACING DAMAGED WIRING, USE EQUIVALENT TYPE AND GAUGE.

W

POWER

LOUVER/

NC

GY

FLAME C URREN T TEST PIN S

BLOWER

VENTER

LOW

OPTIONAL

CONTACTS

HIGH

R

BK

W

NC

NO

GY

C

NO

W

LR

BK/

STATUS

C

BK/W

-

+

F2

F1

BK

S1

LINE

+

3

5

412

-

GY

GY

TRIAL

BK

G

BURNER

GROUND

Y

TD

R

R

BL

PR

ALARM

CONTACTS

PR

ALARMS

FIELD SUPPLIED

SAFETY DEVICES

INTERMITTENT

(1) WHERE POSSIBLE, ALL SWITCHES AND CIRCUITRY ARE SHOWN IN THEIR AT REST STATES.

(2) ADDITION OF ENERGY MANAGEMENT SYSTEMS OR OPTIONAL LIMIT SWITCHES TO THE TERMINAL

NOTES:

PR PR

FIELD SU PPLIED

CONTINUOUS

SAFETY DEVICES

PR

-ENERGIZED BEFORE

PR PR

PR

THIS HEATER MAY BE CONNECTED TO ONE OR

BRANCH CIRCUITS ARE DE

WARNING:

ENSURE ALL

ATTEMPTING TO SERVICE THIS EQUIPMENT.

MORE BRANCH CIRCUITS. TO PREVENT ELECTRICAL SHOCK,

W

W

Neutral

60Hz

120 VAC

15AMPS

BK

Line

G

CHASSIS

Groun d

PR

BL

W

120

VAC

BK

BK BK

2

1

ON/OF F

POWER

SWITCH

BK

GROUND

Y

RUN-TIME

CONTACTS

OPTIONA L

P

P

LOW FIRE VA LVE(S)

RUN-TIME RELA Y

NO

RT

C

R

Y

Y

W

S2/ FS

NEU

GY

GY

IGNITER

R

MODULE

IGNITION

PI

24COM

24VAC

MV

TH

11

10

M/S2FF

RESET

9

7

5PS4

8

6

3

T/

W

P

BL

O

BL/W

LOUVER

PROVING

T

RESETS

BL

LOW AIR

PURGE

O

BL

Y

CONTACTS

SILENCE

OPTIONA L

ALARM BELL

B3

B1 B2

BR

STAGE #1

A3

A1 A2

ALARMS

O/

HiGas

LoGas

NO

LIMIT

AUX. HI-

2

NO

HI-LIMIT

+

BL

24

VAC

Y

-

INLET

O/BK

SENSOR

OPTIONAL

BR

ANY FAILURE

CN3

INLET

PROBE

CN2

O/BK

1

NC

NO

~

~

C

~

~
~

~

O

FACTOR Y FLOW SWIT CH

OPERATOR

2-STAGE THERMOSTAT

O

CN8

CN7

BR

BR

1C 1NO

LOW FIRE

P

PU

NO

DC 24V COIL

PUMP RELAY

BK

C

BL & Y = 24VAC

C

PR

Y

BL

O

2

3

J3

T

546

BL/

BK

BK

BL/

O

NC

O.C.

LWCO

24 VAC

C

J1

T

BR

1

NC

C

BL

PR

TEST

SWITCH

T

RESET

PROBE

~

~

~

~

~

~

~

~

~

~

~

~

BL

BL

BREAKER

CIRCUIT

Y

SAFETY DEVI CES

FIELD INS TALLED

A1 B1A2 A3 B2 B3

CONTINUOUS INTERMITTENT

Y

YR/BK

STAGE #1 LED

NC

R

R

R

1

PR/BK

R

BR

CN4

2

C

NC

W

BK

SOURCE

TO POWER

PR

1

J4

O

J2

321

RESET

P

PR

BL

Y

FAIL

FAIL

OK OK

COM COM

STAGE #2 LED

HIGH FIRE V ALVE(S)

NO

C

R/BK Y

HL

ITEM INDICATES

R/BK

SPEED CONTROL RELAY

HIGH/LOW FIRE & BLOWER

R/BK

2C 2NO

HIGH FIRE

STAGE #2

R/BK

ALARM

SYSTEM/TA NK

R/BK

PR

CN5

PROVIDED IF

BLANK COVER

3

4

PUMP

OPTIONA L ON

GND

GROUN D
CHASSIS

OPTIONA L

BK

PR/

FFR

BK

PR/

BK

PR/

BL

SENSOR

PR

SYS/

TANK

CN6

CN9

OPTION IS

PROVIDED

NO I/O RESET

2

1

CN1

Y

BL

BK

BOILER

BOARD

I/O RESET

OPTIONA L

PR/BK

PR/BK

O.A.

SENSOR

Y

Y

Y

MONITORED

INTERMITTENTLY

SHOWN WI TH SHORT ING

DEVICES IN NON-ALARM STATE.

BARS REMOVED AND ATTACHED

MONITORED

EXAMPLE DEVICES:

NOTE:

HIGH/LOW G AS, AUX. HI-LIMIT

CONTINUOUSLY

AUX. LIMITS, EXT. FLOW SWITCH

JUNCTI ON POINT

(ELECTRICALLY SAME)

P

Y

NONCNO

C

BOILER ONLY

ENABLE

SENSOR

ON

CN7

= RELAYS LOCATED ON CONTROL

Y=YELLOW

R=RE D

T=TA N

BR=BROWN

G=GREEN

GY=GRAY

EQUIPMENT

DOTTED LINE

CLOSED END SPL ICE

INDICATES OPTIONAL

LBL20014 REV- A

Y/G = YELLOW WIT H GREEN STRIPE

W = WHITE

PR=PURPLE

BL=BLUE

P=PINK

BK = BLACK

O=ORAN GE

Y

Y

PR

NO

CONTACTS

ANY FAILURE

AL

C

C

P

BL

PR Y

PR

OFFS ET

HIGH-FIRE

DIFFERENTIAL

CONNECTS HERE

SETPOINT

OFF

TO

CN9

W3

W2

W1

DISABLE

SHUTDOWN

O.A.

O.A. MA X. RAT IO

SHUTDOWN

= OPTIONAL DIN RAIL CONNECTORS

LOCATED IN ELECTRICAL WIRING BOX.

PANEL

= RELAYS LOCATED IN WIRING BOX

= LEDS LOCATED ON DISPLAY BOARD

R

R

51

WIRING DIAGRAM - CONTROL BOX CONNECTIONS
MODELS 985,000 - 2,065,000 BTU/HR

FLAME FAIL

ENABLE RELAY

24V

OPTIONA L

ALARM

ENABLE RELAY

24V

BK

W

S2/FS

F2

F1

S1

NEU

423

-

+

-

+

IGNITION

MODUL E

TH

10

PI

9

8

24COM

RESET

7

24VAC

6

MV

5

PS4M/S

FF

1

LINE

STG #1

Y

PR

Y

P

BL

PR/

BK

YP

1

23

PR/

BK

OPTION AL

PR Y BL

54321

54321

RUNTIME

MONITORING RELAY

24V

1

2

3 4

TO

LWCO

1

2

4

5

7

8

9

10

11

12

13

15

1

2

3

4

5

6

7

9

LBL20015 REV A

5

1

CONTROL BOX CONNECTIONS

Y

GGY

O

P

Y

BL

R

T/W

PR/BK

GY

BK

W

RYR/BK BKR

BK G W

BK/

W

1 2 3 4

R

R

1

2

3

A

B

E

D

CHASSIS

GROUND

24V

COMMON

AC POWER

CONNECTOR

WIRING BOX

CONNECTOR

MAIN U NIT

CONNECTOR

IGNITE R

CONNECTOR

24V

NEUTRAL

GROUND

GY

P

P

GY

R

3 1

6 549

7

BK

14

CONNECTIO N DIAGRAM A

3

6

8

O

OPERATOR

INLET

PROBE

SYS/

TANK

CN1

CN2

CN3

CN4

CN5

CN6

CN7

CN8

CN9

BR

BR

1

2

3

4

1

2

PR

PR

2-STAGE THERMOSTAT

SHUTDOWN

O.A. MAX. RATIO

O.A.

DISABLE

SHUTDOWN

ON

SENSOR

ENABLE

CN7

OPTIONA L

I/O RESET

T

O

BR

BR

BR

R

R/BK

SENSOR

CONNECTOR

PR/BK

PR/BK

BK/W

GY

GY

P

R/B K

BK

PR/BK

Y

W

BL/W

BL

IGN1

IGN1

P1S2S2+

S2-

+24

COM

ALR

RST1

S1

BK

W

GY

GY

PUMP

BK

CIRCUIT

BREAKER

FLAME

FAIL

RESET #2

FULL-FIRE/

BLOWER RELAY

SOCKET TOP VIEW

W

BL

24VAC XF MR.

120V

24V

G

BL

Y

Y

C

BL

Y

3

2

14

6

BR

BR

PR

PR

PR/BK

PR/BK

O/B

T

Y

BR

T/W

4

5

BL/

BK

W

O

BL/

BK

6 9 12 10 7

3 11 1

T

14

13

15

2

BR

BL

O

R/

BK

R/

BK

ELECTRONIC

CONTROLLER

3 1 98
2

4 76

DISPLAY

BOARD

LINE

CONNECTED UNLESS

ALARM ADDED

PR/BK

PR/BK

F

-24V C OM

PR

Y

BR

P

P

Y

R

BK/W

R

OPTIONAL

RUNTIME

CONTACTS

5

4

123

6

TH

OPTION AL

I/O RESET BOARD

BOILER ONLY

5

BK/W BK

R

R/BK

R/BK

BL/W

BL

BL

BL

R/BK

Y

R

C NO

C NO

NC

BL/W

BL/W

321

8

PR

PR

8

Y

P

P

NOT USED

NOT

USED

PR

SHRINK

TUBING

SHRIN

K

TUBIN

G

123456789

10

11

12

W2

W1

W3

TO

LWCO

3

1

6 5 4

9 7

F

BL

BL/

BK

Y

7

4

6

5

O

CHASSI S GROUND

PR

J3

54

6

1

2 3

O.C.

J

1

J2

3

2

1

J4

P

GND

RESET

O

PR

PR

Y

Y

9

BL

BL/

BK

BL

RESET

PR

PR

T

T

TO TEST SWITC H

T

24 VAC

LWCO

Revision 4 (CB-CW(E)-i&s-04) reflects changes made
to the O.A. section.

Revision 5 (CB-CW(E)-i&s-05) reflects changes made
to text on Page 21 and the LBLs on pages 47-51.

Revision 6 (ECO #C02870) reflects the addition of a
mixing valve to FIG. 41 (page 37) and edits made to the
scald warnings.

CB-CW(E)-i&s-06

CP-5M-1/09