Temperature-Pressure Relief Valve Test; Draining And Flushing - A.O. Smith GPHE 50 Series Instruction Manual

teMperature-pressure relIef valve test

DANGER
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 water discharge will
not cause any property damage, as water may be extremely hot. Use
care when operating valve as the valve may be hot.
To check the relief valve, lift lever at the end of valve several times,
see Figure 28. 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 32. Replace the Temperature-Pressure Relief Valve with a
properly rated/sized new one, see Temperature-Pressure Relief Valve
on page 15 for instructions on replacement.
TEMPERATURE-PRESSURE
DISCHARGE PIPE
fIGure 28.
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 page
14-15. 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.
•
Burn hazard.
•
Hot water discharge.
•
Keep clear of Temperature-
Pressure Relief Valve
discharge outlet.
RELIEF VALVE
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.

draInInG and flushInG

It is recommended that the water heater storage tank be drained and
flushed every 6 months to reduce sediment buildup. The water heater
should be drained if being shut down during freezing temperatures.
See Typical Installation section in this manual for location of the water
heater components described below.
DANGER
to draIn the water heater storaGe tanK:
1. Turn off the electrical supply to the water heater.
2. Turn off the gas supply at the Main Gas Shutoff Valve if
the water heater is going to be shut down for an extended
period.
3. Ensure the cold water inlet valve is open.
4. Open a nearby hot water faucet and let the water run until the
water is no longer hot.
5. Close the cold water inlet valve to the water heater.
6. Connect a hose to the water heater drain valve and terminate
it to an adequate drain.
7. Open the water heater drain valve and allow all the water to
drain from the storage tank.
8. Close the water heater drain valve when all water in the storage
tank has drained.
9. Close the hot water faucet opened in Step 4.
10. If the water heater is going to be shut down for an extended
period, the drain valve should be left open.
to flush the water heater storaGe tanK:
11. Turn off the electrical supply to the water heater.
12. Ensure the cold water inlet valve is open.
13. Open a nearby hot water faucet and let the water run until the
water is no longer hot. Then close the hot water faucet.
14. Connect a hose to the drain valve and terminate it to an
adequate drain.
15. Ensure the drain hose is secured before and during the entire
flushing procedure. Flushing is performed with system water
pressure applied to the water heater.
16. Open the water heater drain valve to flush the storage tank.
17. Flush the water heater storage tank to remove sediment and
allow the water to flow until it runs clean.
18. Clo se t he water heater dr ain valve w hen f lushing is
completed.
19. Remove the drain hose.
20. Fill the water heater - see Filling The Water Heater in this
manual.
21. Turn on electrical supply to place water heater back in
operation.
22. Allow the water heater to complete several heating cycles to
ensure it is operating properly.
32
•
Burn hazard.
•
Hot water discharge.
•
Keep hands clear of drain
valve discharge.