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Replace the Upper Thermostat

The information on this web site is supplemental to the printed instructions that came with your water heater. To reduce the risk of property damage, serious injury or death, read and follow all labels on the water heater and the safety instructions in the printed owner's manual.


Step 1: Tools and Supplies

Meat thermometer
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  • Meat thermometer

  • Non-contact circuit tester

  • Screwdriver

  • New upper thermostat

Step 2: Turn Power OFF

Turn the power to the water heater OFF at the circuit breaker (or remove fuses).
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  • Turn the power to the water heater OFF at the circuit breaker (or remove fuses).

  • WARNING! Working near an energized circuit can result in severe injury or death from electrical shock. Check wires with a volt meter or circuit tester to make sure power is off .

Step 3: Open Electrical Junction Box

<strong>It is not necessary to drain the tank to replace a thermostat.</strong>
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  • It is not necessary to drain the tank to replace a thermostat.

  • Open the electrical junction box on top of the water heater.

Step 4: Check for Electrical Power

Using a non-contact circuit tester, check the power wires to make certain the power is off.
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  • Using a non-contact circuit tester, check the power wires to make certain the power is off.

  • WARNING! Working on an energized circuit can result in severe injury or death from electrical shock. Check wires with a volt meter or circuit tester to make sure power is off.

Step 5: Replace the Junction Box Cover

Replace the cover on the electrical junction box.
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  • Replace the cover on the electrical junction box.

  • WARNING! Be sure all covers are secured to reduce the risk of fire and electric shock.

Step 6: Remove the Heating Element Cover

Remove the upper or lower heating element cover.
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  • Remove the upper or lower heating element cover.

Step 7: Move Insulation Out of the Way

Carefully fold back the insulation.
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  • Carefully fold back the insulation.

Step 8: Remove the Plastic Protector

Remove the plastic protector.
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  • Remove the plastic protector.

Step 9: Verify Thermostat

Make sure the replacement thermostat exactly matches the original thermostat.
  • Make sure the replacement thermostat exactly matches the original thermostat.

Step 10: Disconnect Wires

<strong>Mark the wires with tape so you’ll know how to put them back on.</strong>
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  • Mark the wires with tape so you’ll know how to put them back on.

  • Disconnect the wires from the bad thermostat.

Step 11: Remove Thermostat

Remove the thermostat from the metal mounting clip.
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  • Remove the thermostat from the metal mounting clip.

  • CAUTION: Metal edges may be sharp. Wear protective gloves.

Step 12: Install New Thermostat

Pull the metal mounting clip.
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  • Pull the metal mounting clip.

  • Install the new thermostat in the metal mounting clip.

Step 13: Verify Thermostat is Installed Correctly

Make sure the new thermostat fits tightly against the tank.
  • Make sure the new thermostat fits tightly against the tank.

  • You should NOT be able to slip a business card between the thermostat and the tank. If you can, bend the thermostat mounting clip until the thermostat fits tightly against the tank.

Step 14: Rewire New Thermostat

Attach the wires following the wiring diagram on the water heater’s label. Make sure all wire connections are tight.
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  • Attach the wires following the wiring diagram on the water heater’s label. Make sure all wire connections are tight.

Step 15: Verify Temperature Settings

Make sure both thermostats are set no higher than 120°F.
  • Make sure both thermostats are set no higher than 120°F.

  • WARNING! Higher temperatures increase the risk of scalding, but even at 120°F, hot water can scald. Install point-of-use Thermostatic Mixing Valves to reduce the risk of scalding.

Step 16: Replace Plastic Protector

Replace the plastic protector.
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  • Replace the plastic protector.

Step 17: Replace Insulation

Replace the insulation.
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  • Replace the insulation.

Step 18: Replace the Heating Element Cover

Replace the heating element cover.
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  • Replace the heating element cover.

  • WARNING! Be sure covers are secured to reduce the risk of fire and electric shock.

Step 19: Turn Power ON

Turn power to the water heater ON.
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  • Turn power to the water heater ON.

  • It may take up to two hours for the water to heat up.

Step 20: Verify Water Temperature

Check the water temperature after two hours and make sure it is not too hot.
  • Check the water temperature after two hours and make sure it is not too hot.