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Fit T & P valve insulation over valve. Make sure that the insulation
does not interfere with the lever or block the discharge opening
of the T & P valve.
Secure all insulation using tape.
Temperature-Pressure Relief Valve
This heater is provided with a properly certied combination
temperature - pressure relief valve by the manufacturer.
The valve is certified by a nationally recognized testing
laboratory that maintains periodic inspection of production of
listed equipment as meeting the requirements for Relief Valves
and Hot Water Supply Systems, ANSI Z21.22 and the code
requirements of ASME.
If replaced, the valve must meet the requirements of local codes,
but not less than a combination temperature and pressure relief
valve certied as indicated in the above paragraph.
The valve must be marked with a maximum set pressure not to
exceed the marked hydrostatic working pressure of the water
heater (150 psi = 1,035kPa) and a discharge capacity not less than
the water heater input rate as shown on the model rating plate.
For safe operation of the water heater, the relief valve must not
be removed from its designated opening nor plugged.
The temperature-pressure relief valve must be installed directly
into the tting of the water heater designed for the relief valve.
Position the valve downward and provide tubing so that any
discharge will exit only within 6 inches (153 mm) above, or
at any distance below the structural oor, see Figure 17. Be
certain that no contact is made with any live electrical part.
The discharge opening must not be blocked or reduced in
size under any circumstances. Excessive length, over 30 feet
(9.14 m), or use of more than four elbows can cause restriction
and reduce the discharge capacity of the valve.
No valve or other obstruction is to be placed between the relief
valve and the tank. Do not connect tubing directly to discharge
drain unless a 6 inch air gap is provided. To prevent bodily
injury, hazard to life, or property damage, the relief valve must
be allowed to discharge water in quantities should circumstances
demand. If the discharge pipe is not connected to a drain or other
suitable means, the water ow may cause property damage.
FIGURE 17.
The Discharge Pipe:
• Shall not be smaller in size than the outlet pipe size of the
valve, or have any reducing couplings or other restrictions.
• Shall not be plugged or blocked.
• Shall be of material listed for hot water distribution.
• Shall be installed so as to allow complete drainage of both the
temperature-pressure relief valve, and the discharge pipe.
• Shall terminate at an adequate drain or external to the structure.
• Shall not have any valve between the relief valve and tank.