John Wood Commercial Electric Water Heater - Manual (Page 21)

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Water heater is noisy:
1. The heater makes sizzling and hissing noises operating.
• The accumulation of sediment or lime scale may be the
cause. The sounds are normal; however, the tank bot-
tom and elements should be cleaned. Follow the instruc-
tions given in “Draining, Flushing and Sediment
Removal”.
2. Some of the electrical components of the water heater
controls make noises.
• Most of these are normal. Contactors will "click" or snap
as the heater starts and stops, transformers and con-
tacts often hum.
Water leakage is suspected or apparent:
Refer to “Leakage Checkpoints” (Figure 21) to locate poten-
tial leakage points.
1. Make sure the heater drain valve is fully closed.
2. Discharge from the outlet of the T&P relief valve may
indicate:
• Faulty relief valve.
• Excessive water temperature.
• Excessive water pressure.
A common cause of relief valve leakage is excessive water
pressure. This condition is often caused by a "closed sys-
tem”. A closed system has a check valve in the inlet system
that prevents the expanded hot water volume to equalize
pressure with the main system. If a relief valve does not
release this pressure, it will damage the water heater or
plumbing system.
3. Remove the cover and insulation from the element com-
partment.
• Examine the area around the element gasket for leak-
age.
• Tighten the elements if necessary. If tightening the ele-
ments does not stop the leak it may be necessary to
replace the gaskets.
IF YOU CANNOT IDENTIFY OR CORRECT THE SOURCE
OF MALFUNCTION
1. Turn the electrical supply to the heater “OFF”.
2. Close the cold water supply valve.
3. Call a qualified service technician.