Installation Sheet

EX07200-88 Rev. A

TEMPERATURE AN D PRESSURE RELIEF VALVE

CAUTION: To reduce the risk of excessive pressures and temperatures in this electric mini tank water heater,

install temperature and pressure protective equipment required by local codes, but no less than a

combination temperature and pressure relief valve certified as meeting the requirements for Relief Valves

and Automatic Gas Shutoff Devices for Hot Water Supply Systems, ANSI Z21.22, by a nationally recognized

testing laboratory that maintains periodic inspection of production of listed equipment or materials. The

valve must be oriented, provided with tubing, or otherwise installed so that discharge can exit only within 6

inches above, or at any distance below, the structural floor and cannot contact any live electrical part.

Install a discharge pipe from the temperature/pressure relief valve terminating at a sink or drain. DO NOT

CAP OR PLUG THE END OF THE DISCHARGE PIPE. THE DISCHARGE PIPE MUST BE UNOBSTRUCTED AND FULL

SIZED.

The T/P valve is certified by a nationally recognized test lab that maintains periodic inspections of the listed

equipment and meets the requirements for relief valves and automatic shut off devices for hot water supply

systems ANSI Z21.22.

The T/P valve is marked with a maximum pressure, which does not exceed the maximum working pressure of

the water heater (150 PSI).

Install the T/P valve into the threaded opening at the top of the water heater and orient the discharge tubing

so that any discharge from the valve will exit within 6 inches above, or at any distance below the structural

floor, and cannot contact any live electrical part.

T/P VALVE DISCHARGE PIPE

1. Must NOT be smaller in diameter than the outlet diameter of the valve, or have any reducing

couplings.

2. Must NOT be plugged or blocked.

3. Must be made of suitable material for hot water.

4. Must NOT be over 15’ in length.

5. Must NOT have more than two elbows.

6. Must terminate at an adequate drain.

7. Must NOT have a shut off valve between relief valve and tank or relief valve and termination of

discharge.

CLOSED SYSTEM THERMAL EXPANSION

Periodic discharge of the T/P relief valve or failure of the element gasket may be due to thermal expansion in

a closed water supply system. The water utility supply meter may contain a check valve, backflow preventer

or water pressure reducing valve which will create a closed water system. During the heating cycle of the

water heater, the heated water expands causing pressure inside the water heater to increase. The T/P relief

valve may discharge hot water under these conditions which results in a loss of energy and a buildup of lime

on the relief valve seat. To prevent this from happening, there are two recommendations:

1. Install a diaphragm-type domestic hot water expansion tank (suitable for potable water) 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.

2. Install a 125 PSI pressure relief valve in the cold water supply line. Make sure the discharge of this

valve is directed to an open drain and protected from freezing. Contact your local water utility or

plumbing inspector for information on how to control this situation. Never plug the outlet of the

relief valve.