How to Repair a Water Heater Pressure Relief Valve

The hot water heater is one of a few major appliances in your home and requires some regular maintenance to keep it running safely. On a yearly basis you should check your hot water heaters pressure relief valve to make sure it is not leaking. This valve relieves the water pressure if it gets above 150 psi and every hot water heater is required to have this part as it is a safety device.

Things you'll need:

• Hacksaw


• Adjustable wrench


• Replacement relief valve


• Thread seal tape


• Water hose


• Hammer

1. Turn off the gas to the water heater as well turning the temperature valve to the lowest setting. If it is an electric heater then you will need to switch the circuit breaker off in the breaker box.


2. Close the cold water cut-off valve going into the water heater by turning it clockwise. You will also need to relieve the pressure in the tank by turning on a hot water faucet close to the heater.


3. Open the valve at the bottom and drain a little water out of the tank. Drain until it is just below the pressure relief valve. You will need to connect a hose to the drain valve and either place the other end of the hose outside or in a tub.


4. Remove the overflow pipe from the pressure relief valve. This may have to be cut off using a hack saw because sometimes they are glued on.  


5. Take a pipe wrench to unscrew the old pressure relief valve. Sometimes you will have to take a hammer and hit the end of the wrench to loosen the valve.


6. Wrap Teflon tape entirely around the threads of the new valve, and then use an adjustable wrench to tighten the new valve into the water heater.


7. Reattach the relief valve drainpipe using Teflon tape on all the threads. You may need to replace the drainpipe, make sure to use CPVC pipe and glue that is specifically for water heaters.


8. Detach the hose from the water heater and turn the cold water back on. As it begins to fill the tank, turn a hot water faucet on and keep an eye on the pressure. When you are satisfied, you can turn your faucet off and make sure to check for any leaks around your new valve.