A.O. Smith VB/VW-500 User Manual

GAS-FIRED COPPER BOILERS FOR

HYDRONIC HEATING AND HOT W ATER SUPPLY

INSTRUCTION MANUAL

• Installation

• Operation

• Maintenance

• Limited W arranty

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.

— WHA T TO DO IF YOU SMELL GAS:

• 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.

MODELS:

VB/VW-500, 750 AND 1000

SERIES 100/101

— Installation and service must be

performed by a qualified installer, service agency or the gas supplier.

MC BEE, SC., RENTON, WA.,

STRATFORD-ONTARIO, VELDHOVEN-THE NETHERLANDS,

NANJING, CHINA

www.hotwater.com / email: parts@hotwater.com

PRINTED 0207 212800-000

SAFE INSTALLATION, USE AND SERVICE

Your safety and the safety of others is extremely important in the installation, use, and servicing of this boiler.

Many safety-related messages and instructions have been provided in this manual and on your own boiler to warn you and others of a potential injury hazard. Read and obey all safety messages and instructions throughout this manual. It is very important that the meaning of each safety message is understood by you and others who install, use, or service this boiler.

All safety messages will generally tell you about the type of hazard, what can happen if you do not follow the safety message and how to avoid the risk of injury.

IMPORT ANT DEFINITIONS

• Qualified Installer: A qualified installer must have ability equivalent to a licensed tradesman in the fields of plumbing, air supply , venting and gas supply, including a thorough understanding of the requirement s of the National Fuel Gas Code as it relates to the installation of gas fired boilers. The qualified installer must have a thorough understanding of this instruction manual.

• Service Agency: A service agency also must have ability equivalent to a licensed tradesman in the fields of plumbing, air supply , venting and gas supply, including a thorough understanding of the requirement s of the National Fuel Gas Code as it relates to the installation of gas fired boilers. The service agency must also have a thorough understanding of this instruction manual, and be able to perform repairs strictly in accordance with the service guidelines provided by the manufacturer .

• Gas Supplier: The Natural Gas or Propane Utility or service who supplies gas for utilization by the gas burning

appliances within this application. The gas supplier typically has responsibility for the inspection and code approval of gas piping up to and including the Natural Gas meter or Propane storage tank of a building. Many gas suppliers also offer service and inspection of appliances within the building.

GENERAL SAFETY

DIMENSION AND CAP ACITY DA T A

Minimum clearances to combustibles:

• 4” (102mm) rear

• 0” (0mm) top & sides

• 6” (152mm) vent

FIGURE 1.

TABLE 1, GAS AND ELECTRICAL CHARACTERISTICS

Manifold Pressure Maximum Supply Pressure Minimum Supply Pressure

Model Type of Gas Inches W.C. kPa Inches W.C. kPa Inches W.C. kPa

VB/VW-500, 750, 1000 NATURAL -2 to 3.5 -.5 to .9 11.0 3.44 4.0 2.0 VB/VW-500, 750, 1000 PROPANE -2 to -3.5 -.5 to .9 13.8 3.44 8.0 2.0

Minimum Pressures must be maintained during all operating conditions. Electrical Power: 120v, 60hz, and 30 amps.

TABLE 2. ROUGH-IN DIMENSIONS

Models VB/VW-500 VB/VW-750 VB/VW-1000

Dimensions inches mm inches mm inches mm

Flue Outlet Diameter 6 152 6 152 6 152 Air Intake Diameter 4 102 4 102 4 102 Water Inlet 2” NPT Water Outlet 2” NPT Gas Inlet 1” NPT

A 56 1422 62 1575 71 1803 B 30 762 30 762 30 762 C 30 762 30 762 30 762 D 45 1143 51 1295 59 1499 E 36 914 42 1067 48 1219 F 16.5 419 16.5 419 16.5 419 G 8 203 8 203 8 203 H 15 381 15 381 15 381 J 9 229 9 229 9 229 K 11.5 292 11.5 292 11.5 292

L 11 279 11 279 11 279 M 10.5 267 10.5 267 10.5 267 N 33 838 33 838 33 838

P 31 787 31 787 31 787

TABLE 3. RECOVERY CAPACITIES.

Model

No.

Input

Rating

Btu/hr

Output Rating

Btu/hr

VW-500 500,000 421,500 VW-700 750,000 633,750

1000

1,000,000 845,000

CAPACITY AND FLOW DATA

Water

Flow

40 60 80 90 100 120 140

(22) (33) (44) (90) (56) (67) (78)

GPH 1,268 845 634 563 507 423 362

LPH 4,797 3,198 2,399 2,132 1,919 1,599 1,371

GPH 1,901 1,268 951 845 761 634 543

LPH 7,196 4,797 3,598 3,198 2,878 2,399 2,056

GPH 2,535 1,690 1,268 1,127 1,014 845 724 VW-

LPH 9,595 6,397 4,797 4,264 3,838 3,198 2,741

Temperature Rise - °F (°C)

TABLE 4. PUMPING PERFORMANCE GUIDE.

VB MODELS - FLOW, HEAD LOSS AND TEMPERATURE RISE

20F° (11°C)

MODEL GPM L PH

VB-500 42 159 1.8 0.5 28 106 1.3 0.4 21 79 1.0 0.3 100 379 3.8 1.2 8 4 21 79 1.0 0.3 40 22

VB-750 63 238 2.9 0.9 42 159 2.1 0.6 32 121 1.8 0.5 110 416 4.3 1.3 12 7 32 121 1.8 0.5 40 22

VB-1 000 85 322 3.9 1.2 56 212 2.8 0.9 42 159 2.3 0.7 120 454 4.9 1.5 14 8 42 159 2.3 0.7 40 22

Ct 30F° (17°C)

P FT

P m GPM LPH

Ct 40F° (22°C)

P FT

P m GPM LPH

Ct Maximum Flow Rate Minimum Flow Rate

P FT

P m GPM LPH

P FT

P m

T °F

T °C GPM LPH

P FT

P m

T °F

T °C

CONTENTS

SAFE INSTALLATION, USE, AND SERVICE................................. 2

GENERAL SAFETY .......................................................................... 3

DIMENSION AND CAPACITY DATA ............................................ 4-5

TABLE OF CONTENTS ................................................................... 6

INTRODUCTION ............................................................................ 6-7

Grounding Instructions ................................................................. 7

Inlet Water Considerations.......................................................... 7

Correct Gas ................................................................................. 7

Precautions................................................................................... 7

Liquefied Petroleum Gas Models .................................................

High Altitude Installations ............................................................ 7

Field Installed Components......................................................... 7

Panels and Covers...................................................................... 7

FEATURES........................................................................................ 7

The Control System .................................................................... 8

Hot Surface Igniter ...................................................................... 8

Blocked Exhaust Pressure Switch.............................................. 8

Blower Prover Switch .................................................................. 8

Optional Low/High Gas Switch ................................................... 8

Water Flow Switch ...................................................................... 8

Flame Sensor .............................................................................. 8

Water Temperature Limit Controls .............................................. 9

On/Off Switch............................................................................... 9

Circulating Pump ......................................................................... 9

Remote Probe.............................................................................. 9

Low Water Cutoff (Optional)....................................................... 9

Safety Relief Valve................................................................. 9-10

GENERAL

Required Ability .......................................................................... 10

Location ...................................................................................... 10

Panels and Covers............................................................... 10-11

Chemical Vapor Corrosion ........................................................ 11

Installation Clearances ............................................................... 11

Leveling ...................................................................................... 11

Air Requirements .................................................................. 11-12

VENTING.................................................................................... 12

Special Installation Considerations .......................................... 12

Venting System Using AL 29-4C®........................................... 12

General Exhaust Vent Installation Procedure .......................... 12

Connecting Vent to Boiler......................................................... 12

Venting Supports........................................................................ 13

Vertical Installation Requirements ............................................. 13

Horizontal Installation Requirements.................................... 13-14

Direct Vent Installation Requirements....................................... 15

Installation Requirements for the Commonwealth of Mass ...... 15

SYSTEM INSTALLATION .............................................................. 18

General...................................................................................... 18

Hot Water Heating (Hydronic) Equipment ..................................18

Internal Contaminants ................................................................19

Hot Water Supply System General Water Line Connections ......19

Hard Water Conditions...............................................................19

Thermal Expansion (Closed System). ........................................19

Remote Probe Installation Procedure....................................19-20

Gas Connections ..................................................................20-22

Gas Supply Line Sizing ..............................................................22

Wiring ........................................................................................22

SUGGESTED PIPE SIZING TABLES ............................................. 23

CONNECTION DIAGRAM .........................................................24-25

SCHEMATIC DIAGRAM .................................................................26

OPERATION...................................................................................27

Important ...................................................................................27

General...................................................................................... 27

Filling and Purging for Heating Boiler Installation........................27

Filling for Hot Water Supply Boiler Installation............................27

Purging Gas Line .......................................................................27

Inlet Gas Pressure .....................................................................27

Water Temperature Regulation ..................................................28

Manifold Pressure Connections .................................................28

Dipswitches................................................................................29

LIGHTING AND OPERATING INSTRUCTIONS .............................30

Adjustment................................................................................. 31

Setting of the Test Mode ............................................................31

Control System ..........................................................................31

Operating Sequence ..................................................................32

UIM Operating Procedures ........................................................33

Operating Setpoint Adjustment Procedure ............................35-36

TROUBLESHOOTING IGNITION SYSTEM ...................................37

Troubleshooting Gas V alve ........................................................38

PREVENTATIVE MAINTENANCE ..................................................38

Main Burners ........................................................................38-39

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

Combustion Air Filter ..................................................................39

Blower Compartment ................................................................. 39

Burner Maintenance...................................................................39

Condensate Removal System ....................................................39

Venting Maintenance ................................................................. 40

Heat Exchanger Preventive Maintenance...................................40

Tube Cleaning Procedure .......................................................... 40

REPLACEMENT PARTS ................................................................40

LIMITED WARRANTY ....................................................................43

INTRODUCTION

This design complies with the current edition of the ANSI Z21.13 low-pressure boiler standard.

Compliance under this standard implies that when the boiler underwent test, the gas manifold and control assembly provided on the boiler met safe lighting and other performance criteria.

Detailed installation diagrams are found in this manual. These diagrams will serve to provide the installer a reference for the materials and methods of piping necessary. It is essential that all water, gas piping and wiring be installed as shown on the diagrams. You should thoroughly read and understand this manual before installation and/or operation of this boiler.

The factory warranty will be improperly installed or operated.

void if the boiler(s) have been

AL 29-4C® is a registered trademark of Allegheny Ludlum Corporation.

In addition to these instructions, the boiler(s) 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 should be consulted before installations are made.

In the absence of local codes, the installation must comply with the current editions, as follows:

In the United States: The National Fuel Gas Code, ANSI Z223.1/NFPA 54 and the National Electric Code, NFPA 70.

GROUNDING INSTRUCTIONS

This boiler must be grounded in accordance with the National Electrical Code and/or local codes. Boiler is polarity sensitive; correct wiring is imperative for proper operation.

LP gas is present or even suspected, do not attempt to find the cause yourself. Leave the building, leaving doors open to ventilate, then call your gas supplier or service agent. Keep area clear until a service call has been made.

This boiler must be connected to a grounded metal, permanent wiring system, or an equipment grounding conductor must be run with the circuit conductors and connected to the equipment grounding terminal or lead on the boiler.

INLET W A TER CONSIDERA TIONS

To minimize the amount of condensate, a minimum inlet water temperature to the heat exchanger of 120°F (49°C) shall be maintained. This temperature can be acquired by

returning 120°F (49°C) water from the remote storage tank to the boiler or by installing a by-pass loop between the boiler’s inlet and outlet connections. When installing a bypass loop, a remote probe MUST be used, see SYSTEM INSTALLATION.

Circulating water through the boiler and to the remote storage tank (if applicable) is accomplished by a pump on VW models only. For hot water heating systems using the VB model, the circulating pump is NOT provided on standard models (optional) and must be field installed.

CORRECT GAS

MAKE SURE THE GAS ON WHICH THE BOILER WILL OPERATE IS THE SAME AS THAT SPECIFIED ON THE BOILER RATING PLATE. DO NOT INSTALL THE BOILER IF EQUIPPED FOR A DIFFERENT TYPE OF GAS — CONSULT YOUR SUPPLIER.

At times you may not be able to smell an LP gas leak. One cause is odor fade, which is a loss of the chemical odorant that gives LP gas its distinctive smell. Another cause can be your physical condition, such as having a cold or diminishing sense of smell with age. For these reasons, the use of a propane gas detector is recommended.

IF YOU EXPERIENCE AN OUT OF GAS SITUATION, DO NOT TRY TO RELIGHT APPLIANCES YOURSELF. Call your local service agent. Only trained LP professionals should conduct the required safety checks in accordance with industry standards.

HIGH ALTITUDE INSTALLATIONS

PRECAUTIONS

IF THE UNIT IS EXPOSED TO THE FOLLOWING, DO NOT OPERATE UNTIL ALL CORRECTIVE STEPS HAVE BEEN MADE BY A QUALIFIED SERVICEMAN:

1. EXPOSURE TO FIRE.

2. IF DAMAGED.

3. FIRING WITHOUT WATER.

4. SOOTING.

IF THE BOILER HAS BEEN EXPOSED TO FLOODING, IT MUST BE REPLACED.

LIQUEFIED PETROLEUM GAS MODELS

Boilers for propane or liquefied petroleum gas (LPG) are different from natural gas models. A natural gas boiler will not function safely on LP gas and no attempt should be made to convert a boiler from natural gas to LP gas.

LP gas must be used with great caution. It is highly explosive and heavier than air. It collects first in the low areas making its odor difficult to detect at nose level. If

Rated inputs are suitable up to 6000 feet (1829m) elevation. Consult the factory for installation at altitudes over 6000 feet (1829m).

FIELD INSTALLED COMPONENTS

When installing the boiler, the following components MUST be installed:

1) Circulating Pump (Hydronic)

2) Tank Temperature Control Probe (Hot Water Supply)

3) Remote Temperature Control Probe (Hydronic)

4) Storage Tank T&P Relief Valve

5) Manual Gas Shutoff Valve (Supply)

Check the FEATURES AND CONTROLS section for further information.

FEATURES

THE CONTROL SYSTEM

The control system consists of four basic components:

1) Modulation Control Board (MCB); 2) Power Distribution Board (PDB); 3) Variable Frequency Drive (VFD), see Figure 2; 4) User Interface Module, see Figure 19. The Modulation Control Board and the Power Distribution Board are located in the control box and can be accessed by opening the front door of the unit. The User Interface Module is attached to the front door panel. Every system will have one Modulation Control Board (MCB), one Power Distribution Board (PDB), and one User Interface Module (UIM).

The MCB contains dipswitches which are used to configure the boiler for several different control options, see the Control

System Section.

FIGURE 2.

HOT SURF ACE IGNITER

The Hot Surface Igniter is a device that ignites the main burner by high temperature (>1800°F) [982°C], see Figure 3. The igniter is made of recrystallized silicon carbide, and when 120 V AC is applied to the igniter, sufficient heat is generated to ignite the main burner. Although improvements have been made to strengthen the igniter , it is still fragile and care must be taken in handling the igniter to prevent breakage.

The high BPS closes only when the blower is in pre and post purge. If the high BPS closes at any time during the heating cycle, the boiler will shut off.

OPTIONAL LOW/HIGH GAS SWITCH

This VF boiler is available with optional low and high gas pressure switches which meet the CSD-1 code requirements, see Figure 5. The low gas switch is normally closed and remains closed unless pressure falls below the preset pressure. The high gas switch is normally closed and remains closed unless pressure exceeds the preset pressure.

FIGURE 5. LOW/HIGH GAS PRESSURE SWITCH.

W ATER FLOW SWITCH

The water flow switch is installed at the boiler outlet to prevent burner operation in the event of inadequate water flow through the boiler. It is a normally open switch that will close its contacts when increasing water flow rate is detected. The water flow switch is factory-set. The contacts will open when the flow rate drops below the factory setting causing the gas valve to close which will turn off the gas to the burner, see Figure 6. Under no circumstances shall the flow switch be tampered with or bypassed. Doing so may cause damage to the heat exchanger not covered under the warranty.

FIGURE 3.

FIGURE 4.

BLOCKED EXHAUST SWITCH

The Blocked Exhaust Switch, see Figure 4, ensures that the vent system is clear. This exhaust switch is normally closed and only opens on fault conditions.

BLOWER PROVER SWITCH

This VF boiler has two blower prover switches (BPS). The low blower prover switch is a single-pole, normally open pressure switch that closes on increased negative pressure. The low BPS closes when the blower starts and remains closed during the operation of the heating cycle.

The second BPS is the high BPS. It is also a single-pole, normally open pressure switch that closes on increased negative pressure.

FIGURE 6. WATER FLOW SWITCH.

FLAME SENSOR

Each Boiler is equipped with two flame senors coupled together to detect the presence of the burner flames at high and low fire conditions. These flame rods work together as one to sense the flame. If no flame is sensed, the gas valve(s) will close

automatically . If no flame is sensed on three ignition trials, the boiler will lock out. In the event of a lockout, depress the SELECT button on the display board to restart the boiler.

WATER TEMPERATURE LIMIT CONTROLS

FOR HOT WATER HEATING BOILERS-VB models, a remote

probe is supplied due to the various types of systems and operating conditions. A remote probe can be used as an option to control loop temperature and unit staging. Additionally, the inlet temperature probe can be used as the loop thermostat in some heating applications. The remote probe connects to designated wires in the junction box at the rear of the boiler, refer to the PROBE INSTALLATION section. Do not operate this boiler using the

internal high limits only; use a remote probe or operating thermostat to control system temperatures.

The “V(B/W)” models incorporate an outlet water probe consisting of two limit controls:

1. An adjustable automatic high limit control that can be set as high as either 210°F (99°C) or 235°F (113°C), depending on the application.

2. A fixed manual high limit (ECO), factory set at 244°F (118°C). If the manual reset should open due to high temperature, the gas valves will close and the unit will go into lockout. If lockout occurs, push the SELECTION button on the UIM to restart the boiler.

ON/OFF SWITCH

The ON/OFF Switch is a single-pole, single-throw rocker switch. This switch provides 120V from the line source to the boiler.

CIRCULA TING PUMP

HOT WATER SUPPLY BOILER-VW, the circulating pump is

integral to the VW models. This pump has been lubricated at the factory, and future lubrication should be in accordance with the motor manufacturer’s instructions provided as a supplement to this manual.

FOR HOT WATER HEATING BOILERS-VB MODELS, the circulating pump is NOT provided on standard models (optional) and must be obtained and installed in the field.

LOW WATER CUTOFF (Optional)

If low water detection is required by the authorities having jurisdiction, a low water cutoff switch should be installed next to the boiler in the outlet water line as shown in Figure 13. The switch should receive periodic (every six months) inspection to assure proper operation. A Low Water Cutoff device of the float type should be flushed every six months.

SAFETY RELIEF V AL VE

NOTE: If a system pump is to be installed on a VB

model, the maximum rating of the pump motor must not exceed 1 hp.

REMOTE PROBE

FOR HOT WATER SUPPLY BOILERS-VW models, a remote

probe is supplied with each hot water supply boiler. The inlet water temperature and the tank temperature are displayed separately on the default menu screen.

Note: The remote probe must be designated as the controlling probe using dipswitch “4” on MCB before it can be used for VW hot water supply applications, see page 29 (MCB -T en Position Dip Switch). “Pigtails” of field-supplied yellow wires located in the rear of the unit in the junction box should be spliced to “pigtails” of remote probe and connected in the junction box. See Figure 7 for probe installation.

Encase field-supplied wires between remote probe and junction box with 1/2" field supplied conduit. "Pigtails" of field-supplied wires should be spliced to "pigtails" of remote probe. This conduit and wiring should be separate from any other conduit/wiring to guard against EMI (electromagnetic interference).

The purpose of a safety relief valve is to avoid excessive pressure or temperature into the steam range which may cause scalding at fixtures, tank explosion, system damage, or boiler damage.

To avoid scalding or water damage, a drain line must be connected to a safety relief valve to direct discharge to a safe

FIGURE 7. REMOTE PROBE INSTALLATION.

location. A drain line must not contain any valves between the boiler and the relief valve, or the relief valve and the drain exit. In addition, there should not be any restrictions in a drain line nor should it be routed through areas where freezing conditions might occur. Do not thread or cap the drain line exit. Restricting or blocking a drain line will defeat the purpose of the safety relief valve and may create an unsafe condition. Install a drain line with a downward slope such that it will naturally drain itself.

Your local code authority may have other specific safety relief valve requirements not covered below. If any pressure relief valve is replaced, the replacement valve must comply with the current version of the ASME Boiler and Pressure Vessel Code, Section IV (“HEATING BOILERS”).

Select a relief valve with a discharge rating NOT LESS than the boiler input, and a set pressure NOT EXCEEDING the working pressure of any component in the system.

FOR VW HOT WATER SUPPLY BOILERS, the units are shipped with a 125 psi (860kPa) pressure relief valve that must be installed in the water outlet as near to the boiler as possible.

In addition, a CSA design-certified and ASME-rated temperature and pressure (T&P) relief valve must be installed on each and every water storage tank in the hot water supply system. The T& P relief valve must comply with the applicable construction provisions of the Devices for Hot Water Supply Systems, ANSI Z21.22 or CAN/ CSA-B149.1-00, or current edition. The T&P relief valve must be of the automatic reset type and not embody a single-use type fusible plug, cartridge or linkage.

The T&P relief valve should have a temperature rating of 210°F (99°C), a pressure rating NOT exceeding the lowest rated working pressure of any system component, and a discharge capacity exceeding the total input of the water boilers supplying water to the storage tank.

Locate the T&P relief valve (a) in the top of the tank, or (b) in the side of the tank on a centerline within the upper 6 inches (152mm) of the top of the tank, see Figures 13 and 14. The tapping shall be threaded in accordance with the current edition of the Standard for Pipe Threads, General Purpose (inch), ANSI/ASME B1.20.1. The location of, or intended location for, the T&P relief valve shall be readily accessible for servicing or replacement.

Standard for Relief Valves and Automatic Gas Shutoff

This ASME-rated valve has a discharge capacity that exceeds the maximum boiler input rating and a pressure rating that does not exceed the maximum working pressure shown on the boiler rating plate.

GENERAL

REQUIRED ABILITY

INSTALLATION OR SERVICE OF THIS BOILER REQUIRES ABILITY EQUIV ALENT TO THAT OF A LICENSED TRADESMAN IN THE FIELD INVOLVED. PLUMBING , AIR SUPPLY, VENTING, GAS SUPPLY, AND ELECTRICAL WORK ARE REQUIRED.

LOCATION

When installing the boiler, consideration must be given to proper location. The location selected should provide adequate air supply and be as centralized with the piping system as possible.

FOR VB HOT WATER HEATING BOILERS, the units are shipped with a 50 psi (345kPa) pressure relief valve. This relief valve must be installed in the water outlet as near to the boiler as possible.

If the boiler is installed above radiation level, a Low Water Cutoff

Device must be installed in the boiler outlet at the time of installation.

PANELS AND COVERS

All panels and covers (e.g. control and junction box covers; front, side and rear panels of boiler, see Figure 8) MUST be in place after service and/or before operation of the boiler. This will ensure that all gas ignition components will be protected from water.

The VF is a low-pressure boiler (Category IV) to be used as either hot water supply (domestic/commercial water heating) or hot water heating (hydronic) application. Category IV boilers operate with a positive vent pressure and with a vent gas temperature less than 120°F (49°C) above its dew point. Category IV appliances are often termed “High Efficiency” appliances.

FIGURE 8.

CHEMICAL VAPOR CORROSION

Boiler corrosion and component failure can be caused by the heating and breakdown of airborne chemical vapors. Spray can propellants, cleaning solvents, refrigerator and air conditioning refrigerants, swimming pool chemicals, calcium and sodium chloride (water softener salt), waxes, and process chemicals are typical compounds which are potentially corrosive. These materials are corrosive at very low concentration levels with little or no odor to reveal their presence.

Products of this sort should not be stored near the boiler . Also, air which is brought in contact with the boiler should not contain any of these chemicals. If necessary, uncontaminated air should be obtained from remote or outside sources. Failure to observe this requirement will void the warranty.

shall be wide enough to allow the boiler to enter or to permit the replacement of another appliance such as a boiler.

LEVELING

Each unit should be checked after installat ion to be cer tain that it is level.

If the unit is not level, obtain and insert shims under the feet at the frame base to correct this condition.

AIR REQUIREMENTS

INST ALLA TION CLEARANCES

This boiler MUST NOT be installed on carpeted floors. This boiler is approved for installation on combustible flooring in an alcove with minimum clearances to combustibles of:

4" (1 02mm) Rear; 0" (0mm) T op and Sides; 6" (152mm) Vent. 2” (51mm) clearance is allowable from combustible construction for hot water pipes.

Sufficient area should be provided at the front and rear of the unit for proper servicing. Service clearances of 24" (610mm) in front, rear, top and sides are recommended. In a utility room installation, the door opening

UNCONFINED SPACE

In buildings of conventional frame, brick or stone construction, unconfined spaces may provide adequate air for combustion.

If the unconfined space is within a building of tight construction (buildings using the following construction: weather stripping, heavy insulation, caulking, vapor barrier, etc.), air for combustion, ventilation, and draft hood dilution must be obtained from outdoors or spaces freely

FIGURE 9. SIDEWALL EXHAUST VENTING

communicating with the outdoors. The installation instructions for confined spaces in tightly constructed buildings must be followed to ensure adequate air supply .

CONFINED SPACE

When drawing combustion and dilution air from inside a conventionally constructed building to a confined space, such a space shall be provided with two permanent openings, ONE IN OR WITHIN 12 INCHES (305mm) OF THE ENCLOSURE TOP AND ONE IN OR WITHIN 12 INCHES (305mm) OF THE ENCLOSURE BOTTOM. Each opening shall have a free area of at least one square inch per 1000 Btu/hr (2,225mm

per kw) of the total input of all appliances in the enclosure,

but not less than 100 square inches (645cm2). If the confined space is within a building of tight construction, air for

combustion, ventilation and draft hood dilution must be obtained from outdoors. When directly communicating with the outdoors or communicating with the outdoors through vertical ducts, two

VENTING

permanent openings, located in the aforementioned manner, shall be provided. Each opening shall have a free area of not less than one square inch per 4000 Btu/hr (551mm

per kw) of the total input of all appliances in the enclosure. If horizontal ducts are used, each opening shall have a free area of not less than one square inch per 2000 Btu/hr (1,101mm

per kw) of the total input of all appliances in

the enclosure. Where power vented equipment is used in the same room as the

boiler, sufficient air openings must be supplied. UNDERSIZED OPENINGS MAY RESULT IN INSUFFICIENT AIR FOR

COMBUSTION. Where an exhaust fan is installed in the same room with the

boiler, sufficient openings for air must be provided in the walls.

UNDERSIZED OPENINGS WILL CAUSE AIR TO BE DRAWN INTO THE ROOM THROUGH THE CHIMNEY OR OTHER OPENINGS, CAUSING POOR COMBUSTION. SOOTING MAY RESULT WITH AN INCREASED RISK OF ASPHYXIATION.

Special consideration is recommended, before locating the vent termination near walkways, windows and building entrances.

Direct venting into dead spaces such as alleys, atriums, and inside corners can cause recirculation of flue gases. Recirculation of flue gases will cause sooting, premature failure of the heat exchanger, and icing of the combustion air intake during severe cold weather. To prevent the recirculation of flue gases, maintain as much distance as possible between the combustion air intake and the exhaust vent terminal. Due to large volumes of flue gases, multiple boiler applications also require additional distance between the intake and exhaust terminals.

Additional care must be exercised to assure proper draft. For proper operation, a minimum draft of -0.02” W .C. and a maximum draft of

-0.04” W.C. is recommended when vertically vented. Draft should be measured 2 feet (0.6m) above the boiler vent collar.

VENT SIZING, INSTALLATION AND TERMINATION SHALL BE IN ACCORDANCE WITH THIS INSTALLATION MANUAL.

ALL ELECTRICAL POWER AND GAS MUST BE TURNED OFF PRIOR TO ANY INSTALLATION OF THE VENTING SYSTEM.

SPECIAL INST ALLA TION CONSIDERA TIONS

This boiler is a category IV appliance that can be vented using room air for intake combustion air, or direct vented so that all intake air for combustion comes from the outside through a sealed pipe. When installing this appliance as direct vent, special vent kits are required.

In cold climates any water vapor remaining in the flue gases will condense into a cloud of vapor at the point where the vent system exits the building.

VENTING SYSTEM USING AL 29-4C

This boiler may be installed in four separate orientations depending on the requirements of the building and the appliance. The inst aller must decide which method is most appropriate for each installation. These orientations are:

1. Vertical Termination - vertical vent termination through un-

enclosed or enclosed areas with roof penetration, see Figure 11.

2. Through-the-Wall Termination (TWT) - horizontal vent

termination directly through an outside wall, see Figure 11A.

3. Horizontal Direct Vent - using TWT to exhaust flue products

and PVC piping to bring combustion air to the boiler from the outside, see Figures 12 and 12C.

4. Vertical Direct V ent - using a vertical vent termination to exhaust

flue products and PVC piping to bring combustion air to the boiler from outside, see Figures 12A and 12B.

GENERAL EXHAUST VENT INSTALLATION PROCEDURE

Prior to beginning the installation of the vent system, determine and obtain all part s required for the installation. IF THIS INSTALLA TION IS A DIRECT VENT INSTALLA TION A DIRECT VENT KIT IS REQUIRED. REFER TO THE P ARTS LIST FOR KIT NUMBER.

Proper operation of the boiler and venting system is dependent upon use of all specified parts and installation techniques; both safety and proper performance of the system may suffer if instructions are not followed.

CONNECTING VENT TO BOILER

At the outlet of the boiler vent, see Figure 10, the AL 29-4C® Vent Boot-T ee and Boot-T ee Drain Cover must be used as the transition

from the horizontal to vertical run. This is where the bottom most support bracket should be located.

The Boot-Tee Drain Cover is required in order to dispose of the condensate from the venting system. The plastic tube (3/8 [9mm] ID, 10 feet [3m] long) needed to route the condensate to a suitable drain is provided with the boiler.

1. Attach the Boot Tee Drain Cover to the appropriate leg of the Boot-Tee, see Figure 10.

2. A trap loop must be formed into the drain tube simply by looping the tube to a minimum 3 inch (76mm) diameter and secure the loop with a cable tie, see Figure 10.

3. Prior to final assembly the trap loop must be “primed” by pouring a small quantity of water into the drain hose.

4. Connect the Boot-Tee and Drain Tee assembly to the boiler vent connector, see Figure 10.

5. Attach the hose to the drain fitting and run the hose to a sanitary sewer drain maintaining the proper trap loop and following all local, state and federal codes and regulations for draining of acidic effluent (condensate).

Figure 10.

VENTING SUPPORTS

Care must be taken in the installation of the venting system that adequate support is maintained throughout the installation process. When extending more than 10 feet (3.0m) vertically, vertical support kits are required once every 10 feet (3.0m) of vertical run. Vertical support is also required immediately after any transition (elbow, tee, etc.) to vertical of over 10 feet (3.0m) of run and after any offset in the vertical run.

The support brackets (supplied in the Vertical Support Kit) are to be securely fastened to a solid vertical member of the building using the appropriate fasteners; i.e., wood screws for wood framing, machine or tapping screws for structural steel or masonry anchors for solid masonry . The bracket should be located so that it will not interfere with any joints of the venting system. The bottom most support bracket should be located directly above the first transition from horizontal to vertical, see Figure 10. Refer to Figures 12, 12A, 12B and 12C.

If a means of support for the brackets are not available and horizontal vent sections are present, install hanger straps (made from non-combustible material) as close to the points of transition as possible. If the horizontal portions of the vent and/or vent connector are longer than 6 feet (2.0m), then install hanger straps every 6 feet (2.0m) to support the connector.

DO NOT rivet or screw the straps to the conduit or otherwise puncture the conduit wall. Instead, wrap an extra loop of strap around the conduit to hold it in position, or attach the strap to the center screw of the double wall AL 29-4C

vent coupling, if applicable.

VERTICAL INST ALLA TION REQUIREMENTS

1. The vent system must terminate at least 3 feet (1.0m) and no more than 6 feet (2.0m) above the roof line and no closer than 10 feet (3.0m) from any wall or vertical structure. If the exhaust vent terminal is within 10 feet (3.0m) of a wall or parapet, it must extend a minimum of 2 feet (610mm) above the wall or parapet, see Figures 11 and 12A.

2. For direct vent installations, the total distance of the vent system from the boiler vent connector to the vertical vent termination shall not exceed 70 equivalent feet (21.3m). A maximum of three 90° elbows can be used. Minimum vertical vent is 7 equivalent feet (2.1m) for direct vent installations. Standard minimum vertical vent length is 7 feet (2.1m), plus Boot-T ee. See Figures 1 1, 12A, 12B, and 12C for differences between standard and direct vent installations.

3. An AL 29 -C

Vent Vertical Vent Terminal must be used at

the termination.

4. Maintain a minimum of 6 feet (2.0m) separation between the air intake and the exhaust terminals.

HORIZONTAL INSTALLATION REQUIREMENTS

1. The vent system must terminate with a AL 29-4C® Vent Through-the-Wall Termination (TWT). Plan the terminal location based on the dimensions shown in Figure 9. Do not locate the terminal within 8 feet (2.5m) of an inside corner of a building or adjacent to outside walls, shrubs or other such objects that may cause adverse wind conditions in the immediate area.

2. The TWT shall be located not less than 12 inches (305mm) above grade or, in geographical areas where snow accumulates, no less than 12 inches (305mm) above the anticipated snow line. Ensure that the TWT is protected against blockage which may occur during ice buildup or snowstorms.

The TWT shall terminate at least 3 feet (1.0m) above any forced air inlet within 10 feet (3.0m), except when the forced air inlet is the combustion air intake of a direct vent appliance. The TWT shall terminate at least 4 feet (1.2m) below, 4 feet (1.2m) horizontally from or 1 foot (305mm) above any door, window or gravity air inlet into any building as provided in the current edition of the NATIONAL FUEL GAS CODE ANSI Z223.1, see Figure 9.

In addition, a minimum clearance of 4 feet (1.2m) horizontally from, and in NO CASE ABOVE OR BELOW, unless the 4 feet (1.2m) of horizontal distance is maintained from electric meters, gas meters, regulators and relief equipment.

3. This horizontal exhaust vent system must pitch upward toward the termination at 1/4 inch per foot (21mm per meter).

4. The TWT is designed such that the building is protected from degradation by flue gas and condensate. However, if additional protection is desired, install against the wall a non-corrosive metal sheet under the TWT.

5. Due to the normal formation of water vapor in the combustion process, horizontal terminations must not be located over areas of pedestrian or vehicular traffic, (i.e., public walkways or over areas where condensate could create a nuisance or hazard). This is especially true in colder climates where ice buildup is likely to occur. A.O. Smith Corporation will not be held liable for any personal injury or property damage due to any dislodging of ice.

NOTES: If the exhaust vent terminal is within 10’ (3.0m) of a wall or parapet, it must extend a minimum of 2’ (610mm) above the wall or parapet.

Joints are not joined to show vent pipe orientation.

NOTES: Joints are not joined to show vent pipe orientation.

FIGURE 11. VERTICAL TERMINATION.

FIGURE 11A. HORIZONTAL THROUGH THE WALL TERMINATION (TWT).

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