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48
MAINTENANCE
TEMPERATURE-PRESSURE RELIEF VALVE TEST
Burn hazard.
Hot water discharge.
Keep clear of Temperature-
Pressure Relief Valve
discharge outlet.
It is recommended that the Temperature-Pressure Relief Valve
should be checked to ensure that it is in operating condition every
6 months.
When checking the Temperature-Pressure Relief Valve operation, make
sure that (1) no one is in front of or around the outlet of the Temperature-
Pressure Relief Valve discharge line, and (2) that the water discharge
will not cause any property damage, as the water may be extremely
hot. Use care when operating valve as the valve may be hot.
To check the relief valve, lift the lever at the end of the valve several times,
see Figure 37. The valve should seat properly and operate freely.
If after manually operating the valve, it fails to completely reset
and continues to release water, immediately close the cold water
inlet to the water heater and drain the water heater, see Draining
And Flushing on page 47. Replace the Temperature-Pressure
Relief Valve with a properly rated/sized new one, see Temperature-
Pressure Relief Valve on page 17 for instructions on replacement.
DISCHARGE PIPE
TEMPERATURE-PRESSURE
RELIEF VALVE
FIGURE 37.
If the Temperature-Pressure Relief Valve on the water heater
weeps or discharges periodically, this may be due to thermal
expansion.
NOTE: Excessive water pressure is the most common
cause of Temperature-Pressure Relief Valve leakage.
Excessive water system pressure is most often caused by
“thermal expansion” in a “closed system.” See Closed Water
Systems and Thermal Expansion on pages 15 and 16. The
Temperature-Pressure Relief Valve is not intended for the
constant relief of thermal expansion.
Temperature-Pressure Relief Valve leakage due to pressure
build up in a closed system that does not have a thermal
expansion tank installed is not covered under the limited
warranty. Thermal expansion tanks must be installed on all
closed water systems.
DO NOT PLUG THE TEMPERATURE-PRESSURE RELIEF
VALVE OPENING. THIS CAN CAUSE PROPERTY DAMAGE,
SERIOUS INJURY OR DEATH.
Explosion Hazard
Temperature-Pressure Relief Valve
must comply with ANSI Z21.22-
CSA 4.4 and ASME code.
Properly sized temperature-
pressure relief valve must be
installed in opening provided.
Can result in overheating and
excessive tank pressure.
Can cause serious injury or death.