Rheem 311 Series Owner's Manual And Installation Instructions page 56

REGULAR CARE
TEMPERATURE PRESSURE RELIEF VALVE
This valve is near the top of the water
heater and is essential for its safe
operation. It is possible for the valve to
release a little water through the drain
line during each heating period. This
occurs as the water is heated and
expands by approximately 1/50 of its
volume.
Continuous leakage of water from the
valve and its drain line may indicate a
problem with the water heater (refer to
"Temperature Pressure Relief Valve
Running" on page 18).
Warning: Never block the outlet of
this valve or its drain line for any
reason.
Operate the easing lever on the
temperature pressure relief valve once
every six months. It is very important
you raise and lower the lever gently.
Warning: Failure to do this may
result in the water heater cylinder
failing.
Warning: Exercise care to avoid
any splashing of water, as water
discharged from the drain line will be
hot. Stand clear of the drain line‟s point
of discharge when
valve‟s lever.
If water does not flow freely from the drain line when the lever is lifted, then the
water heater must be checked. Phone Rheem Service or their nearest
Accredited Service Agent to arrange for an inspection.
The temperature pressure relief valve should be replaced at intervals not
exceeding 5 years, or more frequently in areas where there is a high incidence
of water deposits (refer to
operating the
"Water Supplies"
12
lift until water
flows from the drain
drain line –
line
lower gently
on page 13).
water
heater