Troubleshooting Checklist; Not Enough Or No Water; Water Is Too Hot; Water Heater Makes Strange Sounds - A.O. Smith DVE-150, DHE-200 Installation And Operaion Manual

Before calling for service, check the following points to see if the
cause of trouble can be identified and corrected. Reviewing this
checklist may eliminate the need of a service call and quickly restore
hot water service.
The illustration in the Features and Components section of this
manual identifies the location of most of the heater components,
see Pages 6 and 7.
BE SURE TO TURN OFF THE ELECTRICITY (ELECTRICAL
DISCONNECT SWITCH) WHEN CHECKING EQUIPMENT.
not enouGh or no hot water
1. Be certain the electrical disconnect switch serving the water
heater is in the ON position. The pilot toggle switch on the cabinet
should be ON.
In some areas water heater electrical service may be limited by the
power company. If the heater operates on a controlled circuit, heater
recovery may be affected.
The optional manual override switches on the cabinet front may be
turned off, de-energizing the elements.
2. Check the fuses.
The electrical disconnect switch usually contains fuses.
The water heater has fuses located behind the cabinet front door,
see the Features and Components section of this manual on pages
6 and 7.
3. If the water was excessively hot, and is now cold, the temperature
hi-limit cutoff may have tripped open.
To reset, turn off the electricity, open the control cabinet door, and
push the reset button.
Repeated operation of the temperature hi-limit cutoff should be
investigated by a qualified installer or service agency.
4. The storage capacity and/or recovery rate of the water heater
may have been exceeded by a large demand for hot water. See
pages 5 and 11.
Large demands require a recovery period to restore water temperature.
5. Cold incoming water temperature will lengthen the time required
to heat water to the desired temperature.
If the heater was installed when incoming water temperature was
warm, colder water creates the effect of less hot water.

trouBleshootInG checklIst

7. Sediment or lime scale may be affecting water heater operation.
Refer to the MAINTENANCE section of this manual for details.

water Is too hot

Refer to the TEMPERATURE REGULATION section of this manual.

water heater Makes stranGe sounds

1. Sediment or lime scale accumulations on the elements causes
sizzling and hissing noises when the heater is operating.
The sounds are normal, however, the tank bottom and elements
should be cleaned. Refer to MAINTENANCE section of this manual
for details.
2. Some of the electrical components of the water heater make
sounds which are normal ie. contactors will "Click" or snap as the
heater starts and stops.

leakaGe checkpoInts

1. Check to see if the drain valve is tightly closed.
2. The apparent leakage may be condensation which forms on cool
surfaces of the heater and piping.
3. If the outlet of the relief valve is leaking it may represent:
Excessive water pressure.
Excessive water temperature.
Faulty relief valve.
Excessive water pressure is the most common cause of relief valve
leakage. Water supply systems may, because of code requirements
or such conditions as high line pressure, among others, have installed
devices such as pressure reducing valves, check valves, and back
flow preventers. Devices such as these cause the water system to
be a closed system.
As water is heated, it expands (thermal expansion). In a closed
system the volume of water will grow when it is heated. As the
volume of water grows there will be a corresponding increase in
water pressure due to thermal expansion. Thermal expansion can
cause intermittent temperature-pressure relief valve operation:
water discharged from the valve due to excessive pressure build
up. This condition is not covered under the limited warranty. The
temperature-pressure relief valve is not intended for the constant
relief of thermal expansion.
A properly sized thermal expansion tank should be installed on all
closed systems to control the harmful effects of thermal expansion.
Contact a local qualified service agency to have a thermal expansion
tank installed.
4. Examine the flange area of the elements for gasket leakage.
Tighten the bolts or, if necessary, follow the WATER AND LIME
SCALE REMOVAL procedure in the MAINTENANCE section of this
manual to replace the gaskets.
If you cannot IdentIfy or correct the source
OF MALFUNCTION:
1. Place the water heater electrical disconnect switch in the OFF
position.
2. Close the cold water inlet valve to the heater.
3. Contact the A.O. Smith Water Products Company Customer Care
Center at 800-527-1953.
17