State Water Heaters RESIDENTIAL ELECTRIC WATER HEATER, Service Handbook

Page: 23 / 38

RESIDENTIAL ELECTRIC WATER HEATER
SERVICE HANDBOOK
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Technical Training Department
22 of 36 Residential Electric Svc Handbook
Ashland City, Tennessee ©2004 STC082
Connection to an off-peak clock interrupts power to the lower thermostat and heating
element during the designated time period but does not interrupt power to the upper
thermostat. If the consumer uses enough of the stored hot water to drop tank
temperature at the top of the tank to call for upper element activation, then the upper
element will reheat the upper third of the tank. This installation typically requires a
larger volume tank to give the homeowner as much hot water as possible while the
clock has the power interrupted.
VOLTAGE CHECKS
These tests are conducted on the water heater, below the junction box.
Complaint: No Hot Water
Test Conditions:
Tank is full of cold water (or at least 15
°
F below the upper
thermostat setting).
Power on: Upper thermostat calling for heat
Multi-meter set to the proper AC voltage scale.
Test between upper high limit terminals 1 and 3
If … … then
the proper voltage is not present
(disconnect) Check the power from the breaker or fused
disconnect.
the proper voltage is present Check the wiring in the water heater
junction box and continue to the next step.
Test between upper high limit terminals 2 and 4
If …
… then
the proper voltage is not present Push the red reset button – if this
establishes proper voltage, conduct the
thermostat and element checks before
changing the high limit.
pushing the reset does not restore voltage Replace the high limit.
the proper voltage is present Continue to the next step.
Test between upper high limit 4 and upper thermostat 2
If …
… then
the proper voltage is not present high limit
4 and upper thermostat 2 Replace the upper thermostat
the proper voltage is present Conduct upper element checks. The top
1/3 of the tank should be hot.
TESTING THE A-9 OFF-PEAK / TIME CLOCK CIRCUIT