Rheem MPi 551 Series Owner's Manual And Installation Instructions page 17

TEMPERATURE PRESSURE RELIEF VALVE RUNNING
Normal Operation
It is normal and desirable this valve allows a small quantity of
water to escape during the heating cycle. However, if it discharges
more than a bucket full of water in 24 hours, there may be another
problem.
Continuous dribble
Try gently raising the easing lever on the relief valve for a few
seconds (refer to
page 11). This may dislodge a small particle of foreign matter and
clear the fault. Release the lever gently.
Steady flows for long periods (often at night)
This may indicate the mains water pressure sometimes rises
above the designed pressure of the water heater. Ask your
installing plumber to fit a pressure limiting valve.
Warning: Never replace the relief valve with one of a higher
pressure rating.
Heavy flows of hot water until the water heater is cold - then stops until water reheats
The water heater must be switched off at the isolating switch or switchboard. Phone Rheem Service or
their nearest Accredited Service Agent to arrange for an inspection.
EXPANSION CONTROL VALVE RUNNING
If an expansion control valve is fitted in the cold water line to the water heater
discharge a small quantity of water instead of the temperature pressure relief valve on the water heater. The
benefit is that energy is conserved as the discharged water is cooler.
"Temperature Pressure Relief Valve"
on
17
SAVE A SERVICE CALL
(refer to page 37) it may