Troubleshooting Tips; For Service - Rheem MHD75245 Use & Care Manual

Before You Call For Service...

Troubleshooting Tips

Save time and money! Review the chart on this page first and you may not need to call for service.
Problem
Rumbling noise
Relief valve pro-
ducing popping
noise or draining
Not enough or no
hot water
Water is too hot
! CAUTION: For your safety DO NOT attempt repair of electrical wiring, thermostats, heating elements or
other safety devices. Refer repairs to qualified service personnel.
Possible Causes
Water conditions in your location
caused a build up of scale or mineral
deposits on the heating elements.
Pressure build up caused by thermal
expansion in a closed system.
Water usage may have exceeded the
capacity of the water heater.
A fuse is blown or a circuit breaker
tripped.
Electric supply may be off.
The thermostat may be set too low.
Leaking or open hot water faucets.
Electric service to your location may
be interrupted.
Improper wiring.
Manual reset limit (ECO).
Cold water inlet temperature may be
colder during the winter months.
Top element defective (no hot water)
Bottom element defective (small
quantity of hot water)
The thermostat is set too high.
Covers and / or insulation missing.
What to Do
Remove and clean the heating elements.

Contact a qualified service technician.
This is an unacceptable condition and

must be corrected. Contact the water
supplier or plumbing contractor on how
to correct this. DO NOT plug the relief
valve outlet.
Wait for the water heater to recover after

an abnormal demand.
Replace fuse or reset circuit breaker.

Make sure electric supply to water heater

and disconnect switch, if used, are in the
ON position.
See the Temperature regulation of the

water heater section of this manual.
Make sure all faucets are closed.

Contact the local electric utility.

See the Installing the water heater section

of this manual.
See the Temperature regulation of the

water heater section of this manual.
This is normal. The colder inlet water

takes longer to heat.
Replace element.

Replace element.

See the Temperature regulation of the

water heater section of this manual.
Reinstall covers and insulation.

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