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Warning, Closed system/thermal expansion, Temperature and pressure relief valve – American Water Heater Power Flex 40-42K BTU User Manual

Page 12

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FIGURE 10A

Temperature and Pressure

Relief Valve Installation

T&P Valve and Pipe Insulation

(Some Models)

1. Locate the T&P Valve on the water heater.
2. Locate the slit running the length of the insulation.
3 Spread this slit open and slip it over the T&P Valve. See

Figure 10B. Apply gentle pressure to the insulation to
ensure it is fully seated on the T&P Valve. Once sealed
secure the insulation with a section of tape.
IMPORTANT: The insulation or tape should not block
or cover the T&P drain opening. Also the insulation or
tape should not block or hinder access to the T&P valve
manual relief lever.

4. Next locate the hot water (outlet) & cold water (inlet) pipes

to the water heater.

5. Select one of the sections of pipe insulation and locate the

slit that runs the length of the insulation.

6. Spread the slit open at the base of the insulation and slip

it over the cold water (inlet) pipe. Apply gentle
pressure along the length of the insulation to ensure it is
fully seated around the cold water pipe. Also ensure that
the base of insulation is flush with the water heater. Once
seated secure the insulation with a section of tape.

7. Repeat steps 5 through 6 for the hot water (outlet) pipe.

T&P Valve

T&P Valve
Drain Line

Manual Relief Lever

T&P Insulation

Figure 10B
T&P Valve Insulation

Closed System/Thermal Expansion

CAUTION - PROPERTY DAMAGE HAZARD

Periodic discharge of the temperature and pressure

relief valve may be due to thermal expansion in a closed

water supply system. The water utility supply meter

may contain a check valve, backfl ow preventer or water

pressure reducing valve. This will create a closed water

system. During the heating cycle of the water heater, the

water expands causing pressure inside the water heater

to increase. This may cause the temperature and pressure

relief valve to discharge small quantities of hot water. This

is an unacceptable condition and must be corrected. To

prevent this, it is recommended that a diaphragm-type

expansion tank (suitable for potable water) be installed

on the cold water supply line. The expansion tank must

have a minimum capacity of 1.5 U.S. gallons for every 50

gallons of stored water. Contact the local water supplier

or plumbing inspector for information on other methods to

control this situation.

Temperature and Pressure
Relief Valve

Explosion Hazard

If the temperature and pressure relief valve
is dripping or leaking, have a qualified
person replace it.

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

Do not plug valve.

Do not remove valve.

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

WARNING

For protection against excessive pressures and

temperatures, a temperature and pressure relief valve must

be installed in the opening marked “T & P RELIEF VALVE”

(see Figure 10A.) This valve must be design certifi ed by

a nationally recognized testing laboratory that maintains

periodic inspection of the production of listed equipment

or materials as meeting the requirements for Relief

Valves for Hot Water Supply Systems, ANSI Z21.22. The

function of the temperature and pressure relief valve is to

discharge water in large quantities in the event of excessive

temperature or pressure developing in the water heater.

The valve’s relief pressure must not exceed the working

pressure of the water heater as stated on the data plate.
IMPORTANT: Only a new temperature and pressure relief

valve should be used with your water heater. Do not use an

old or existing valve as it may be damaged or not adequate

for the working pressure of the new water heater. Do not

place any valve between the relief valve and the tank.

Drain Pan

Discharge line 3/4” min.

Do not cap or plug.

Temperature and

Pressure Relief Valve

Drain

6” max.

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