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Fit T & P valve insulation over valve. Make sure that the insulation
does not interfere with the lever of the T & P valve.
Secure all insulation using tape.
Temperature-Pressure Relief Valve
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.
• Shall not have any valve between the relief valve and tank.
FLOOR DRAIN
DISCHARGE PIPE
(Do not cap or plug)
TEMPERATURE - PRESSURE
RELIEF VALVE
(OPTIONAL TOP T&P RELIEF
VALVE NOT SHOWN)
SHUTOFF
VALVE
DRAFT HOOD
HOT WATER
OUTLET
COLD WATER
INLET
DRAIN VALVE
HOT
COLD
FIGURE 16.
This heater is provided with a properly certifi ed combination
temperature - pressure relief valve by the manufacturer.
The valve is certifi ed by a nationally recognized testing laboratory
that maintains periodic inspection of production of listed
equipment as meeting the requirements for Relief Valves for 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 certifi ed 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 fi 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 fl oor, see Figure 16. 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 fl ow may cause property damage.