A.O. Smith POWER VENT GAS, Installation And Operating Manual

12 www.hotwater.com 

groups or if there is a local code or state law requiring a 
certain temperature water at the hot water tap, then you 
must take special precautions. In addition to using the 
lowest possible temperature setting that satis

fi

 es your hot 

water needs, a means such as a Mixing Valve, should be 
used at the hot water taps used by these people or at the 
water heater (see Figure 3). Mixing valves are available at 
plumbing supply or hardware stores. Consult a Quali

fi

 ed 

Installer or Service Agency. Follow the mixing valve 
manufacturer’s instructions for installation of the valves. 
Before changing the factory setting on the thermostat, read 
the “Temperature Regulation” section in this manual.

 FACTS TO CONSIDER ABOUT LOCATION

Carefully choose an indoor location for the new water 
heater, because the placement is a very important 
consideration for the safety of the occupants in the building 
and for the most economical use of the appliance. 

This 

water heater is not for use in manufactured (mobile) 
homes or outdoor installation.

Whether replacing an old water heater or putting the water 
heater in a new location, the following critical points must 
be observed:

Select a location indoors as close as practical to the 
vent terminal or location to which the water heater vent 
piping is going to be connected, and as centralized 
with the water piping system as possible.
A pressure-reducing valve and/or an expansion tank 
may be required for installations where the water 
pressure is high. The pressure-reducing valve should 
be located on the supply to the entire house in order 
to maintain equal hot and cold water pressure.
Selected location must provide adequate clearances 
for servicing and proper operation of the water 
heater.
Avoid locations that could cause the water heater to 
freeze from outside air.
Selected location must provide access to a properly 
grounded electrical branch circuit. A dedicated circuit 
is preferred. Do not use a GFI outlet.

Important:

 Do not use an extension cord to connect the 

water heater to an electrical outlet.

Important:

 The electrical controls used inside the gas 

control of this water heater are polarity sensitive. Ensure 
the electrical supply is connected correctly in the receptacle 
box. Failure to connect correctly will prevent the unit from 
functioning properly.

Installation of the water heater must be accomplished in 

1.

2.

3.

4.

5.

such a manner that if the tank or any connections should 
leak, the 

fl

 ow will not cause damage to the structure. For 

this reason, it is not advisable to install the water heater 
in an attic or upper 

fl

 oor. When such locations cannot be 

avoided, a suitable metal drain pan should be installed 
under the water heater. Drain pans are available at your 
local hardware store. Such a drain pan must have a 
clearance of at least 1.0 in. (2.5cm) greater than any point 
on the water heater’s outer jacket and must be piped to 
an adequate drain. The pan must not restrict combustion 
air 

fl

 ow. See Figure 1.

Water heater life depends upon water quality, water 
pressure 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 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 drain pan. These devices are highly 
recommended and are available from some plumbing 
supply wholesalers and retailers, and detect and react to 
leakage in various ways:
•  Sensors mounted in the drain pan that trigger an alarm 

or turn off the incoming water to the water heater when 
leakage is detected.

•  Sensors mounted in the drain pan that turn off the water 

supply to the entire building when water is detected in 
the 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.

AVOID AREAS WHERE FLAMMABLE LIQUIDS (VAPORS) 
ARE LIKELY TO BE PRESENT OR STORED (GARAGES, 
STORAGE AND UTILITY AREAS, ETC.): Flammable 
liquids (such as gasoline, solvents, propane (LP or butane, 
etc.) and other substances (such as adhesives, etc.)) emit 

fl

 ammable vapors which can be ignited by a gas water 

heater’s igniter or main burner. The resulting 

fl

 ashback 

and 

fi

 re can cause death or serious burns to anyone in 

the area.

Also, the water heater must be located and/or protected so 
it is not subject to physical damage by a moving vehicle.