A.O. Smith 315456-002, GAHH-50, GAHH-40 User Manual

0 (0)

Installation Instructions and Use & Care Guide

RESIDENTIAL GAS WATER HEATERS

HIGH EFFICIENCY ATMOSPHERIC VENT

GAS WATER HEATER

(FLAMMABLE VAPOR IGNITION RESISTANT)

FOR SPACE HEATING AND POTABLE WATER HEATING ONLY.

NOT FOR USE IN MOBILE HOMES.

This water heater complies with ANSI Z21.10.1-current edition regarding the accidental or unintended ignition of flammable vapors, such as those emitted by gasoline.

• Safety Instructions

• Care and Maintenance

• Installation

• Troubleshooting

• Operation

• Parts List

INSTALLER:

AFFIX THESE INSTRUCTIONS TO OR ADJACENT TO THE WATER HEATER.

OWNER:

RETAIN THESE INSTRUCTIONS AND WARRANTY FOR FUTURE REFERENCE. RETAIN THE ORIGINAL RECEIPT AS PROOF OF PURCHASE.

WARNING: Gas leaks can not always be detected by smell.

Gas suppliers recommend that you use a gas detector approved by UL or CSA.

For more information, contact the your gas supplier.

If a gas leak is detected, follow the “WHAT TO DO IF YOU SMELL GAS” instructions.

For Your Safety

AN ODORANT IS ADDED TO THE GAS USED

BY THIS WATER HEATER.

WARNING: If the information in these instructions is not followed exactly, a fire or explosion may result causing property damage, personal injury or death.

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

ALL TECHNICALAND WARRANTY QUESTIONS: SHOULD BE DIRECTED TO THE LOCAL DEALER FROM WHOM THE WATER HEATER WAS PURCHASED.

IF YOU ARE UNSUCCESSFUL, CONTACT RESIDENTIAL TECHNICALASSISTANCE AT 1-800-527-1953 OR WWW.HOTWATER.COM.

PRINTED IN THE U.S.A 0410

1

PART NO. 315456-002

TABLE OF CONTENTS

 

Water Heater Safety ...........................................................................................................................................................................

1-4

Safe Installation, Use and Service ......................................................................................................................................................

3

Safety Precautions ............................................................................................................................................................................

3-4

Typical Installation ...............................................................................................................................................................................

5

Installing Your Gas Water Heater .....................................................................................................................................................

6-8

Important Information About Your Water Heater ......................................................................................................................

6

Consumer Information .............................................................................................................................................................

6

Consumer Responsibilities ......................................................................................................................................................

6

Unpacking the Water Heater ...................................................................................................................................................

6

Location Requirements ............................................................................................................................................................

7

Site Locations ..........................................................................................................................................................................

7

Clearances and Accessibility ...................................................................................................................................................

8

State of California ....................................................................................................................................................................

8

Gas Supply .......................................................................................................................................................................................

9-10

Gas Requirements ....................................................................................................................................................................

9

Gas Piping ...............................................................................................................................................................................

9

Gas Pressure ...........................................................................................................................................................................

9

Gas Pressure Testing ...............................................................................................................................................................

9

Gas Pipe Capacity Table .......................................................................................................................................................

10

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

11-15

Unconfined Space ...................................................................................................................................................................

11

Confined Space ......................................................................................................................................................................

11

All Air from Inside the Building ...............................................................................................................................................

12

All Air from Outdoors ..............................................................................................................................................................

12

Louvers and Grilles ...........................................................................................................................................................

12-13

Vent Pipe System ..................................................................................................................................................................

13

Draft Hood Installation ......................................................................................................................................................

13-14

Vent Pipe Size .......................................................................................................................................................................

14

Vent Connectors ....................................................................................................................................................................

14

Chimney Connection ..............................................................................................................................................................

14

Vertical Exhaust Gas Vent ................................................................................................................................................

14-15

Water System Piping .....................................................................................................................................................................

15-18

Piping Installation ..............................................................................................................................................................

15-16

Closed System/Thermal Expansion .......................................................................................................................................

16

Temperature & Pressure Relief Valve ...............................................................................................................................

16-17

T&P Relief Valve and Pipe Installation ..................................................................................................................................

17

Combination Space Heating/Potable Water System ........................................................................................................

17-18

Solar Installation ....................................................................................................................................................................

18

Electrical Connections and Wiring Diagram ..........................................................................................................................

18

Important Information About this Water Heater ..............................................................................................................................

19

Operating Your Water Heater .......................................................................................................................................................

20-25

Gas Valve/Thermostat - Lighting Instructions ........................................................................................................................

20

Checking the Draft .................................................................................................................................................................

21

Burner Flames .......................................................................................................................................................................

22

Emergency Shutdown ............................................................................................................................................................

22

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

22-23

Operational Conditions .....................................................................................................................................................

23-24

Routine Preventive Maintenance ...........................................................................................................................................

24

Temperature and Pressure Relief Valve ................................................................................................................................

25

Maintenance of Your Water Heater ..............................................................................................................................................

25-27

Replacement Parts ................................................................................................................................................................

25

Removing the Burner from the Manifold/Burner Assembly ...................................................................................................

25

Replacing the Flame Sense/Hot Surface Igniter Assembly ...................................................................................................

26

External Inspection & Cleaning of the Air Intake Chamber Louvers .....................................................................................

26

Cleaning the Combustion Chamber andAir Diverter Assembly .............................................................................................

26

Replacing the Manifold Burner/Assembly .........................................................................................................................

26-27

Removing and Replacing the Gas Control Valve/Thermostat ...............................................................................................

27

FVIR System Operational Checklist ......................................................................................................................................

28

Troubleshooting Chart ..................................................................................................................................................................

28-29

Control Display Troubleshooting ................................................................................................................................................

30-33

Repair Parts Illustration .....................................................................................................................................................................

34

Listed Parts Kits and Illustrations............................................................................................................................................

35

Notes .... ..........................................................................................................................................................................................

36-38

Warranty ..........................................................................................................................................................................................

39-40

2

SAFE INSTALLATION, USE AND SERVICE

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

Many safety-related messages and instructions have been provided in this manual and on your water heater to warn you and others of a potential 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 water heater.

This is the safety alert symbol. It is used to alert you to potential personal injury hazards. Obey all safety messages that follow this symbol to avoid possible injury or death.

DANGER

 

result in death or injury.

 

 

DANGER indicates an imminently hazardous situation which, if not avoided, will

 

 

 

 

 

result in death or injury.

WARNING

 

 

 

WARNING indicates a potentially hazardous situation which, if not avoided, could

 

 

 

CAUTION

 

result in minor or moderate injury.

 

 

CAUTION indicates a potentially hazardous situation which, if not avoided, could

 

 

 

CAUTION

 

situation which, if not avoided, could result in property damage

 

 

CAUTION used without the safety alert symbol indicates a potentially hazardous

 

 

 

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.

The California Safe Drinking Water and Toxic Enforcement Act requires the Governor of California to publish a list of substances known to the State of California to cause cancer, birth defects, or other reproductive harm, and requires businesses to warn of potential exposure to such substances.

WARNING: This product contains a chemical known to the State of California to cause cancer, birth defects, or other reproductive harm.

This appliance can cause low-level exposure to some of the substances included in the Act.

IMPORTANT DEFINITIONS

Qualified Technician: A qualified technician 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 requirements of the National Fuel Gas Code as it relates to the installation of gas fired water heaters. The qualified technician must also be familiar with the design features and use of flammable vapor ignition resistant water heaters, and 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 requirements of the National Fuel Gas Code as it relates to the installation of gas fired water heaters. 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.

 

SAFETY PRECAUTIONS

 

 

WARNING

 

 

FIRE AND EXPLOSION HAZARD

 

 

Can result in serious injury or death

 

 

Do not store or use gasoline or other

 

 

flammable vapors and liquids in the vicinity of this

 

 

or any other appliance. Storage of or use of

FLAMMABLES

Flammable Vapors

gasoline or other flammable vapors or liquids in the

vicinity of this or any other appliance can result in

 

 

serious injury or death.

Read and follow water heater warnings and instructions.

3

Fire or Explosion Hazard

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

Avoid all ignition sources if you smell Natural or LP gas.

Do not expose water heater control to excessive gas pressure.

Use only gas shown on rating plate.

Maintain required clearances to combustibles.

Keep ignition sources away from faucets after extended period of non-use.

Read instruction manual before installing, using or servicing water heater.

4

TYPICAL INSTALLATION

GET TO KNOW YOUR WATER HEATER - GAS MODELS

A

Vent Pipe

K

Outer door

U

Main Burner

B

Draft hood

L

Union

V

Flue

C

Anode (Not Shown)

M

Inlet Water Shut-off Valve

W

Suitable Metal Drain Pan

D

Hot Water Outlet

N

Cold Water Inlet

X

Control Display

E

Insulation

O

Inlet Dip Tube

Y

Power Supply Transformer

F

Gas Supply Piping

P

Temperature & Pressure Relief Valve

 

(Shown detached from Heater)

G

Manual Gas Shut-off Valve

Q

Rating Plate

YY Pressure Switch

H

Ground Joint Union

R

Flue Baffle

 

(Shown detached from Heater)

I

Drip Leg (Sediment Trap)

S

Gas Control Valve/Thermostat

Z

Air Intake Chamber

J

Inner Door

T

Drain Valve

ZZ

FV Sensor (Shown without Bracket)

*INSTALL IN ACCORDANCE WITH LOCAL CODES.

*DRIP LEG AS REQUIRED

BY LOCAL CODES.

* ALL PIPING MATERIALS

 

TO BE SUPPLIED BY

 

CUSTOMERS.

 

TO VENT TERMINATION

 

ON ROOF

 

A

INSTALL THERMAL EXPANSION

TANK IF WATER HEATER IS

 

 

INSTALLED IN A CLOSED

 

WATER SYSTEM

L

M

N

B

 

 

 

D

 

 

 

O

VACUUM RELIEF

 

 

VALVE

 

 

*INSTALL PER

 

 

LOCAL CODES

E

 

P

 

 

R

X

 

Z

 

Q

F

 

 

 

G

 

 

 

 

 

 

DISCHARGE PIPE

H

 

S

(DO NOT CAP OR PLUG.)

 

 

 

 

V

 

 

 

 

T

I

U

 

 

 

 

6” MAXIMUM

 

 

 

 

 

 

AIR GAP

 

 

 

FLOOR DRAIN

W

 

 

YY

J

ZZ

 

 

 

 

 

 

 

Y

K

 

 

 

 

(S) GAS CONTROL VALVE/THERMOSTAT

IMPORTANT:

WHEN BRUSHING ON AN APPROVED NONCORROSIVE LEAK DETECTION SOLUTION, DO NOT SPLASH SOLUTION ONTO ELECTRICAL CON- NECTIONS (SEE PAGE 27).

MANIFOLD TUBE

 

POWER SUPPLY

IGNITER/

TRANSFORMER

FLAME

CONNECTOR

SENSE

 

CONNECTOR

PRESSURE

SWITCH/FAN,

FV SENSOR

CONNECTOR

DISPLAY, ANODE

ROD CONNECTOR

(U) NATURAL GAS BURNER ASSEMBLY

MANIFOLD DOOR GASKET

 

 

MANIFOLD COMPONENT

MANIFOLD DOOR ASSEMBLY

BLOCK W/ RETAINER CLIP

 

 

BURNER

IGNITER / FLAME SENSE

FLAME SENSE

CONNECTOR WIRE

 

 

MANIFOLD

 

HOT SURFACE

TUBE

IGNITER / FLAME SENSE

 

IGNITER

 

CONNECTOR WIRE

MANIFOLD DOOR ASSEMBLY

 

BURNER

 

 

 

 

MANIFOLD TUBE

 

VIEW PORT

 

IMPORTANT: DO NOT USE AN EXTENSION CORD TO CONNECT

THE WATER HEATER TO AN ELECTRICAL OUTLET.

FIGURE 1.

5

INSTALLING YOUR GAS WATER HEATER

Important Information About This Water Heater

This gas water heater was manufactured to voluntary safety standards to reduce the likelihood of a flammable vapor ignition incident. New technology used in meeting these standards makes this product more sensitive to installation errors or improper installation environments. Please review the Installation Checklist found at the end of the installation instructions section and make any required installation upgrades or changes.

Consumer Information

This water heater is design-certified by CSA International as a Category I, non-direct vented water heater which takes its combustion air either from the installation area or from air ducted to the unit from the outside.

This water heater must be installed according to all local and state codes or, in the absence of local and state codes, the “National Fuel Gas Code”, ANSI Z223.1(NFPA 54)-current edition. This is available from the following:

CSA America, Inc.

8501 East Pleasant Valley Road Cleveland, OH 44131

National Fire Protection Agency 1 Batterymarch Park

Quincy, MA 02269

Check your phone listings for the local authorities having jurisdiction over your installation.

Consumer Responsibilities

This manual has been prepared to acquaint you with the installation, operation, and maintenance of your gas water heater and provide important safety information in these areas.

Read all of the instructions thoroughly before attempting the installation or operation of this water heater.

Do not discard this manual. You or future users of this water heater will need it for future reference.

Service to the FVIR System should only be performed by a qualified technician.

Examples of a qualified technician include: licensed plumbers, authorized gas company personnel, and authorized service personnel.

IMPORTANT: The manufacturer and seller of this water heater will not be liable for any damages, injuries, or deaths caused by failure to comply with the installation and operating instructions outlined in this manual.

If you lack the necessary skills required to properly install this water heater, or you have difficulty following the instructions, you should not proceed but have a qualified technician perform the installation of this water heater. Massachusetts code requires this water heater to be installed in accordance with Massachusetts Plumbing and Fuel Gas Code 248 CMR Section 2.00 and 5.00.

A rating plate identifying your water heater can be found on the front of your water heater. When referring to your water heater, always have the information listed on the rating plate readily available. Retain your original receipt as proof of purchase.

Unpacking the Water Heater

WARNING

Excessive Weight Hazard

Use two or more people to move and install the water heater. Failure to do so can result in injury (including back injury).

IMPORTANT: Do not remove any permanent instructions, labels, or the data label from either the outside of the water heater or on the inside of water heater panels.

Remove exterior packaging and place installation components aside.

Inspect all parts for damage prior to installation and start-up.

Completely read all instructions before attempting to assemble and install this product.

After installation, dispose of/recycle all packaging materials.

6

Location Requirements

WARNING

Carbon Monoxide Poisoning Hazard

Do not install in a mobile home.

Doing so can result in carbon monoxide poisoning and death.

The FVIR System is designed to reduce the risk of flammable vapor-related fires. Flammable liquids (such as gasoline, solvents, propane, etc,) emit flammable vapors which can be ignited by a gas water heater’s hot surface igniter or main burner. The resulting flashback and fire can cause death or serious burns to anyone in the area.

FIGURE 1A.

FV Sensor

This heater is equipped with a FV sensor for detecting the presence of flammable vapors. When the sensor detects those vapors, the unit will shut down and not operate. Should this happen, please refer to the troubleshooting guide on pages 31-32 (numbers 9,11,12). Even though this water heater is a flammable vapors ignition resistant water heater and is designed to reduce the chances of flammable vapors being ignited, gasoline and other flammable substances should never be stored or used in the same vicinity or area containing a gas water heater or other open flame or spark producing appliance.

WARNING

FLAMMABLES

Flammable Vapors

FIRE AND EXPLOSION HAZARD

Can result in serious injury or death

Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance. Storage of or use of gasoline or other flammable vapors or liquids in the vicinity of this or any other appliance can result in serious injury or death.

Read and follow water heater warnings and instructions

Do not use or store flammable products such as gasoline, solvents, or adhesives in the same room or area near the water heater. If such flammables must be used, all gas burning appliances in the vicinity must be shut off and their pilot lights extinguished. Open the doors and windows for ventilation while flammable substances are in use.

If flammable liquids or vapors have spilled or leaked in the area of the water heater, leave the area immediately and call the fire department from a neighbor’s home. Do not attempt to clean the spill until all ignition sources have been extinguished.

WARNING

Fire or Explosion Hazard

Read instruction manual before installing, using or servicing water heater.

Improper use may result in fire or explosion.

Maintain required clearances to combustibles.

Keep combustibles such as boxes, magazines, clothes, etc. away from the water heater area.

Site Location

Select a location near the center of the water piping system. The water heater must be installed indoors and in a vertical position on a level surface. DO NOT install in bathrooms, bedrooms, or any occupied room normally kept closed.

Locate the water heater as close to the chimney or gas vent as practical. Consider the vent system piping and combustion air supply requirements when selecting the water heater location. The venting system must be able to run from the water heater to termination with minimal length and elbows.

Locate the water heater near the existing gas piping. If installing a new gas line, locate the water heater to minimize the pipe length and elbows.

The water heater should be located in an area not subject to freezing temperatures. Water heaters located in unconditioned spaces (i.e., attics, basements, etc.) may require insulation of the water piping and drain piping to protect against freezing. The drain and controls must be easily accessible for operation and service. Maintain proper clearances as specified on the water heater.

Do not locate the water heater near an air-moving device. The operation of air-moving devices such as exhaust fans, ventilation systems, clothes dryers,

fireplaces, etc., can affect the proper operation of the water heater. Special attention must be given to conditions these devices may create. Flow reversal of flue gases may cause an increase of carbon monoxide inside of the dwelling (Figure 2).

The water heater is to be located as close as possible to a 120VAC outlet. NOTE: all electrical wiring should be in accordance to the NEC and all local/state electrical codes (extension cord is not allowed).

NOTE: This water heater must be installed according to all local and state codes or, in the absence of local and state codes, the “National Fuel Gas Code”, ANSI Z223.1(NFPA 54)-current edition and the “National Electrical Code”, ANSI/ NFPS 70 current edition.

7

IMPORTANT: The water heater should be located in an area where leakage of the tank or connections will not result in damage to the area adjacent to the water heater or to lower floors of the structure. Due to the normal corrosive action of water, the tank will eventually leak after an extended period of time. Also any external plumbing leak, including those from improper installation, may cause early failure of the tank due to corrosion if not repaired. If the homeowner is uncomfortable with making the repair a qualified technician should be contacted. A suitable metal drain pan should be installed under the water heater as shown below, to help protect the property from damage which may occur from condensate formation or leaks in the piping connections

or tank. The pan must limit the water level to a maximum depth of 1-3/4” and be two inches wider than the heater and piped to an adequate drain. Locate the water heater near a suitable indoor drain. Outside drains are subject to freezing temperatures which can obstruct the drain line. The piping should be at least 3/4” ID and pitched for proper drainage.

FIGURE 1B.

Pipe to an

 

adequate drain

1-3/4”

max.

At least 2” greater

than the water heater.

Water heater life depends upon water quality, water usage, water temperature and the environment in which the

water heater is installed. Water heaters are sometimes installed in locations where leakage may result in property damage, even with the use of a metal drain pan piped to a drain. However, unanticipated damage can be reduced or prevented by a leak detector or water shut-off device used in conjunction with a piped metal drain pan. These devices are available from some plumbing supply wholesalers and retailers, and detect and react to leakage in various ways:

EXHAUST FAN

REVERSE FLOW

OF GASES

FIGURE 2.

Clearances and Accessibility

NOTE: Minimum clearances from combustible materials are stated on the label on the front of the heater adjacent to the gas control valve/thermostat of the water heater.

The water heater is certified for installation on a combustible floor.

IMPORTANT: If installing over carpeting, the carpeting must be protected by a metal or wood panel beneath the water heater. The protective panel must extend beyond the full width and depth of the water heater by at least five inches (127mm) in any direction; or if in an alcove or closet installation, the entire floor must be covered by the panel.

Figure 2A may be used as a reference guide to locate the specific clearance locations. A minimum of 5 inches of front clearance should be provided for inspection and service.

 

 

 

6” min. at

 

 

 

Single Wall

12” min.

 

 

Vent Pipe

 

 

 

 

 

Top to

 

 

 

 

 

 

Ceiling

 

 

0” min. Back

0” min. Sides

0” min. Air Inlet Chamber

5” min.

Front

Top View

• Sensors mounted in the metal drain pan that trigger an

alarm or turn off the incoming water to the water heater

Minimum Clearance Locations

when water is detected.

 

Sensors mounted in the metal drain pan that turn off the water supply to the entire home when water is detected in the metal drain pan.

Water supply shut-off devices that activate based on the water pressure differential between the cold water and hot water pipes connected to the water heater.

Devices that will turn off the gas supply to a gas water heater while at the same time shutting off its water supply.

FIGURE 2A.

State of California

NOTE: The water heater must be braced, anchored, or strapped to avoid moving during an earthquake. Contact local utilities for code requirements in your area, visit http:// www.dsa.dgs.ca.gov, or call 1-916-445-8100 and request instructions.

8

GAS SUPPLY

WARNING

Explosion Hazard

Use a new CSA approved gas supply line.

Install a shut-off valve.

Do not connect a natural gas water heater to an L.P. gas supply.

Do not connect an L.P. gas water heater to a natural gas supply.

Failure to follow these instructions can result in death, explosion, or carbon monoxide poisoning.

Gas Requirements

IMPORTANT: Read the rating plate to be sure the water heater is made for the type of gas you will be using in your home. This information will be found on the rating plate located near the gas control valve/thermostat. If the information does not agree with the type of gas available, do not install or light. Call your dealer.

NOTE: An odorant is added by the gas supplier to the gas used by this water heater. This odorant may fade over an extended period of time. Do not depend upon this odorant

as an indication of leaking gas.

Gas Piping

The gas piping must be installed according to all local and state codes or, in the absence of local and state codes, the “National Fuel Gas Code”, ANSI Z223.1(NFPA 54)-current edition.

Tables 1 and 2 on the following page provide a sizing reference for commonly used gas pipe materials. Consult the “National Fuel Gas Code” for the recommended gas pipe size of other materials.

NOTE: Use pipe joint compound or teflon tape marked as being resistant to the action of petroleum gases (See Figure 3.)

1.Install a readily accessible manual shut-off valve in the gas supply line as recommended by the local utility. Know the location of this valve and how to turn off the gas to this unit.

2.Install a drip leg (if not already incorporated as part of the water heater) as shown. The drip leg must be no less than three inches long for the accumulation of dirt, foreign material, and water droplets.

3.Install a ground joint union between the gas control valve/thermostat and the manual shut-off valve. This is to allow easy removal of the gas control valve/ thermostat.

4.Turn the gas supply on and check for leaks. Test all connections by brushing on an approved noncorrosive leak-detection solution. Bubbles will show a leak. Correct any leak found.

Manual Gas

Shut-Off Valve

Ground Joint Union

Install a readily accessible manual shut-off valve in the gas supply line as recommended by the local utility.

Check with local utility for minimum height.

3” Minimum

Drip Leg

Discharge Pipe (Do Not plug or cap)

6” Max. Air Gap

Suitable Drain

FIGURE 3.

Gas Pressure

WARNING

Explosion Hazard

Gas leaks can not always be detected by smell.

Gas suppliers recommend that you use a gas detector approved by UL or CSA.

For more information, contact your gas supplier.

If a gas leak is detected, follow the “What to do if you smell gas” instructions on the cover of this manual.

IMPORTANT: The gas supply pressure must not exceed the maximum supply pressure as stated on the water heater’s rating plate. The minimum supply pressure is for the purpose of input

adjustment.

Gas Pressure Testing

IMPORTANT: This water heater and its gas connection must be leak tested before placing the appliance in operation.

If the code requires the gas lines to be tested at a pressure exceeding 14” W.C., the water heater and its manual shut-off valve must be disconnected from the gas supply piping system and the line capped.

If the gas lines are to be tested at a pressure less than 14” W.C., the water heater must be isolated from the gas supply piping system by closing its manual shut-off valve.

NOTE: Air may be present in the gas lines and could prevent the burner from lighting on initial start-up. The gas lines should be purged of air by a qualified technician after installation of the gas piping system. While purging the gas piping system of air, insure that the fuel is not spilled in the area of the water heater installation, or any source of ignition (NOTE: spilled fuel may trip the FV Sensor preventing heater from starting). If the fuel is spilled while purging the piping system of air follow the “WHAT TO DO IF YOU SMELL

GAS” instructions on the cover of this manual.

9

A.O. Smith 315456-002, GAHH-50, GAHH-40 User Manual

Gas Pipe Capacity Table

WARNING

Explosion Hazard

Use a new CSA approved gas supply line.

Install a shut-off valve.

Do not connect a natural gas water heater to an L.P. gas supply.

Do not connect an L.P. gas water heater to a natural gas supply.

Failure to follow these instructions can result in death, explosion, or carbon monoxide poisoning.

WARNING

Explosion Hazard

Gas leaks can not always be detected by smell.

Gas suppliers recommend that you use a gas detector approved by UL or CSA.

For more information, contact your gas supplier.

If a gas leak is detected, follow the “What to do if you smell gas” instructions on the cover of this manual.

10

COMBUSTION AIR & VENTILATION

WARNING

Carbon Monoxide Warning

Water heater must be vented to outdoors.

Vent must be installed by a qualified technician using the installation instructions.

Examples of a qualified technican include: gas technicians, authorized gas company personel, and authorized service persons.

Failure to so do can result in death or carbon monoxide poisoning.

IMPORTANT: Air for combustion and ventilation must not come from a corrosive atmosphere. Any failure due to corrosive elements in the atmosphere is excluded from warranty coverage.

The following types of installation (not limited to the following) will require outdoor air for combustion due to chemical exposure and may reduce but not eliminate the presence of corrosive chemicals in the air:

beauty shops

photo processing labs

buildings with indoor pools

water heaters installed in laundry, hobby, or craft rooms

water heaters installed near chemical storage areas

Combustion air must be free of acid-forming chemicals such as sulfur, fluorine, and chlorine. These elements are found in aerosol sprays, detergents, bleaches, cleaning solvents, air fresheners, paint, and varnish removers, refrigerants, and many other commercial and household products. When

burned, vapors from these products form highly corrosive acid compounds. These products should not be stored or used near the water heater or air inlet.

Combustion and ventilation air requirements are determined by the location of the water heater. The water heater may be located in either an open (unconfined) area or in a confined area or small enclosure such as a closet or small room. Confined spaces are areas with less than 50 cubic feet for each 1,000 BTUH of the total input for all gas-using appliances.

Unconfined Space

A water heater in an unconfined space uses indoor air for combustion and requires at least 50 cubic feet for each 1,000 BTUH of the total input for all gas appliances. The table below shows a few examples of the minimum square footage (area) required for various BTUH inputs.

TABLE 3

 

Minimum

 

BTUH Input

Square

Typical Room

Feet with

with 8’ Ceiling

 

 

8’ Ceiling

 

30,000

188

9 x 21

45,000

281

14 x 20

60,000

375

15 x 25

75,000

469

15 x 31

90,000

563

20 x 28

105,000

657

20 x 33

120,000

750

25 x 30

135,000

844

28 x 30

IMPORTANT:

The area must be open and be able to provide the proper air requirements to the water heater. Areas that are being used for storage or contain large objects may not be suitable for water heater installation.

Water heaters installed in open spaces in buildings with unusually tight construction may still require outdoor air to function properly. In this situation, outside air openings should be sized the same as for a confined space.

Modern home construction usually requires supplying outside air into the water heater area.

Confined Space

For the correct and proper operation of this water heater, ample air must be supplied for the combustion, ventilation, and dilution of flue gases. Small enclosures and confined areas must have two permanent openings so that sufficient fresh air can be drawn from outside of the enclosure. One opening shall be within 12 inches of the top and one within 12 inches of the bottom of the enclosure as shown in Figure 4.

The size of each opening (free area) is determined by the total BTUH input of all gas utilization equipment (i.e., water heaters, furnaces, clothes dryers, etc.) and the method by which the air is provided. The BTUH input can be found on the water heater rating plate. Additional air can be provided by two methods:

1.All air from inside the building.

2.All air from outdoors.

11

12” Max.

Permanent openings to the outside or additional rooms within the building

Closet

or other

confined

space

12” Max.

FIGURE 4.

All Air from Inside the Building

When additional air is to be provided to the confined area from additional room(s) within the building, the total volume of the room(s) must be of sufficient size to properly provide the necessary amount of fresh air to the water heater

and other gas utilization equipment in the area. If you are unsure that the structure meets this requirement, contact your local gas utility company or other qualified agency for a safety inspection.

Each of the two openings shall have a minimum free area of 1 square inch per 1,000 BTUH of the total input rating of all gas utilization equipment in the confined area, but not less than 100 square inches (Figure 5).

Confined

Space

Permanent

Openings

1 Square inch/1000 BTUH (min. 100 sq. in.)

FIGURE 5.

All Air from Outdoors

Outdoor fresh air can be provided to a confined area either directly or by the use of vertical and horizontal ducts. The fresh air can be taken from the outdoors or from crawl or attic spaces that freely communicate with the outdoors.

Attic or crawl spaces cannot be closed and must be properly ventilated to the outside.

Ductwork must be of the same cross-sectional area as the free area of the opening to which they connect. The

minimum dimension of rectangular air ducts cannot be less than three inches.

The size of each of the two openings is determined by the method in which the air is to be provided. Refer to Table 4 to calculate the minimum free area for each opening. Figures 6, 7, 8A and 8B are typical examples of each method.

Louvers and Grilles

In calculating free area for ventilation and combustion air supply openings, consideration must be given to the blocking effect of protection louvers, grilles, and screens. These devices can reduce airflow, which in turn may require larger openings to achieve the required minimum

free area. Screens must not be smaller than 1/4” mesh. If the free area through a particular design of louver or grille is known, it should be used in calculating the specified free area of the opening. If the design and free area are not known, it can be assumed that most wood louvers will allow 20 - 25% of free area while metal louvers and grilles will allow 60 - 75% of free area.

Louvers and grilles must be locked open or interconnected with the equipment so that they are opened automatically during equipment operation.

Keep louvers and grilles clean and free of debris or other obstructions.

TABLE 4

Minimum Free Area of Permanent Openings for Ventilation and Combustion Air Supply - All Air from Outdoors Only.

Based on total BTUH input rating for all utilizing equipment within the confined space.

 

Minimum Free Area

 

Opening Source

Per Opening (sq. in.)

Reference Drawing

*Direct to outdoors

1 sq. in, per 4000 BTUH

Figure 6

Vertical Ducts

1 sq. in, per 4000 BTUH

Figure 7

Horizontal Ducts

1 sq. in, per 2000 BTUH

Figure 8A

Single Opening

1 sq. in, per 3000 BTUH

Figure 8B

Example: A water heater with an input rating of 50,000 BTUH using horizontal ducts would require each opening to have a minimum free area of 25 square inches.

Minimum free area = 50,000 BTUH x 1 sq. in. / 2000 BTUH = 25 sq. in.

*These openings connect directly with the outdoors through a ventilated attic, a ventilated crawl space, or through an outside wall.

Consult the local codes of your area for specific ventilation and combustion air requirements.

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