A.O. Smith GAHH-40, GAHH-50 GAS Supply, Gas Requirements, Gas Piping, Gas Pressure Testing

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

Manual Gas

Shut-Off Valve

Ground Joint Union

Install a readily acces- sible 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

	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.

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.

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