Rheem W2W Series Owner's Manual And Installation Instructions page 13

REGULAR CARE
TEMPERATURE AND PRESSURE RELIEF VALVE AND EXPANSION
CONTROL VALVE
A temperature and pressure relief valve is supplied with the storage tanks. In
many areas, including South Australia, Western Australia and scaling water
areas, an expansion control valve is also fitted to the cold water line to the water
heater system. The expansion control valve may discharge a small quantity of
water from its drain line during the heating period instead of the temperature
pressure relief valve on the storage tanks.
Operate the easing lever on the temperature and pressure relief valve and
expansion control valve once every six months. It is very important you raise
and lower the lever gently.
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 operating the valve's lever.
DANGER: Failure to do this may result in the water heater heat exchanger
failing.
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 (or Service Centre in NZ) to arrange for an inspection.
The temperature and pressure relief and expansion control valve should be
replaced at intervals not exceeding 5 years, or more frequently in areas where
"Water Supplies"
there is a high incidence of water deposits (refer to on page 14)
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