DIY Hot Water Heater Repair

What You'll Need
Replacement Parts
Teflon Tape
Service Manual

Hot water heater repair may intimidate new DIYers, but it is not that complicated. There are several reasons why hot water heaters fail - inefficient or damaged thermostats or heater elements, damaged water tank, or leaky/damaged valves - yet a homeowner can easily solve these issues. Here are some steps


Water heaters are 240-volt appliances and may cause serious electric shock if they are repaired improperly. Therefore, during repairs, it is always safe to turn off the circuit breaker or fuse powering the device and place a sign that anyone should not turn them on. 

Repairing the Thermostat

Obtain a service manual for the water heater and use it as a reference when looking for specific parts. Locate the thermostat and gain access to it. This may require removing the water heater access panel. Remove the wires on the thermostat to prepare it for continuity testing. Use the wiring diagram on the service manual to locate the thermostat terminals. Turn the multitester to read resistance. Touch the probes of the tester to the terminals of the thermostat. If the reading is infinity, it is still functional. If the reading is zero, make sure to purchase an exact replacement and install it.

Repairing the Heating Element

Locate the heating element by removing the access panels on the hot water heater. Detach one of the wires from the heating element and set the multitester to read a resistance of 1000 (RX1000). Touch one of the probes to the terminal screw on the heating element and another probe to the element’s mounting bolt. When the reading is zero and not infinity, it is time to replace the element with a new one.

To replace the element, drain the entire water tank first. Remove the element by detaching the mounting bolts holding it into position. Insert the new element and wire it correctly to the heater by following the appropriate steps detailed in the manual. Make sure to replace any installation gaskets as well.

Repairing the Valves

Inspect both the relief and drain valves for any sign of damage. The relief valve should have a spring lever that can be lifted to check for water flow. Lift the lever and check for water flow. When the relief valve does not spew any water or only allows a few drips to come out, then it needs to be replaced. Check the drain valve as well to see if it has any leaks or damage.

To repair leaks, simply remove the valves from their location using a wrench, remove the pipe tape on the male threads and wrap new Teflon tape at least three times. Re-install the valves. To replace any of the valves, drain the entire water tank. Loosen the valve from the tank using a wrench and pull it out. Purchase a new valve and install it in place.