RESIDENTIAL GAS AND ELECTRIC WATER HEATER
SERVICE HANDBOOK
Residential Electric – continued
Voltage Checks
These tests are conducted on the 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
Multimeter set to the proper AC voltage scale
Test between upper high limit terminals 1 and 3
If … | … then |
the proper voltage is not present | check power from the breaker (fused |
(disconnect) | disconnect). |
the proper voltage is present | check wiring in heater junction box |
| continue to next step. |
Test between upper high limit terminals 2 and 4 | |
If … | … then |
the proper voltage is not present | push the reset button – if this establishes |
| proper voltage, conduct 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 | • check the jumper between upper |
and upper thermostats 2 | thermostat 1 and high limit 2. |
| • replace the upper thermostat |
the proper voltage is present | • conduct upper element checks. |
| • top 1/3 of tank should be hot. |
A.O. Smith Water Products Company | 41 | Training Department | |
©2002 | Ashland City, Tennessee | ||
|
