Things You'll Need:
- Wrench
- Bucket
- Pipe compound
- Match
- Soap and water
- Spounge
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Step 1
Turn off the water heater's supply of gas by first turning the control knob on top of the control box to the "Off" position. Then turn the gas shutoff handle on the in-line valve until the handle is in a position perpendicular to the line. Allow at least fifteen minutes to pass for the gas to dissipate.
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Step 2
Turn off the water heater's supply of cold and hot water by turning the water valves at the top of the heater in a clockwise direction.
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Step 3
Disconnect the gas line which leads to the side of the thermostat with a wrench. Then drain the water within the tank into a bucket by opening the hose bib located on the side of the tank.
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Step 4
Use a wrench to disconnect the three metal lines which attach to the bottom of the thermostat. Then turn the thermostat box in a counterclockwise direction to remove it from the tank.
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Step 5
Twist the replacement thermostat onto the heater's tank. Then reconnect the three metal lines to the bottom of the thermostat with a wrench. Coat the threaded end of the gas supply line with pipe compound, sometimes referred to as "pipe dope," and connect the line to the side of the thermostat.
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Step 6
Turn on the heater's water supply at the two valves above the tank. Then turn on the supply of gas.
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Step 7
Light the pilot light by first twisting the knob on top of the thermostat to the "Pilot" position then by placing a long match next to the burner. Once the burner is lit, press and hold down the "Reset" button on top of the thermostat for about one minute. Then release the reset button and turn the knob on the thermostat to the "On" position. Rotate the dial on the front of the thermostat to between 120 and 125 degrees, or "L" for low.
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Step 8
Check for leaks by first creating a mixture of equal parts soap and water. Then apply the solution to all fittings with a sponge to complete the installation. If leaks are present, bubbles will develop.
