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, backflow 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
Temperature and Pressure
Relief Valve
WARNING
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.
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 certified 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.
FIGURE 10A |
Temperature and Pressure |
Relief Valve Installation |
Temperature and |
Pressure Relief Valve |
Discharge line 3/4” min. |
Do not cap or plug. |
Drain Pan |
6” max. |
Drain |
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.
3Spread 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.
Figure 10B |
T&P Valve Insulation |
T&P Insulation |
Manual Relief Lever |
T&P Valve |
T&P Valve |
Drain Line |
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