How to Replace a Water Heater Temperature and Pressure Release Valve
Every water heater has a temperature and pressure relief valve called a T&P valve for short. It’s an important safety feature that prevents pressure from building up that could damage the heater and even your home. Over time, the temperature & pressure release valve can corrode to the point where it doesn’t work properly. You should be able to open the valve with your hand and hear the pressure escape.
If it doesn’t pass this simple test, it’s time to replace the valve.
For this repair, you’ll need a replacement temperature & pressure release valve, a PVC drain line, a pipe wrench or adjustable wrench, an extension or cheater bar, flat blade screwdriver, Teflon tape, a garden hose, and a few rags and towels. Attach a length of garden hose to the drain valve at the bottom of the heater. Run the other end of the garden hose to the nearest floor drain or to a safe spot outside the home.
Close the shut-off valve at the cold water inlet line. Open a hot-water faucet somewhere in the house that will relieve the system pressure inside the tank. Now, open the drain valve and allow approximately one gallon of water to drain for a top-mounted temperature & pressure release valve or ten gallons for a side-mounted T&P valve. Remember the water will be hot, be sure no one is near the drain hose so they don’t get scalded. Detach the runoff tube connected to the T&P valve. Remove the old T&P valve with the wrench. You may need to use a cheater bar or short length the metal pipe for extra leverage. You may get some additional water draining, so have some rags or towels handy.
Now you’re ready to install the new temperature & pressure release valve
Use Teflon tape to seal the threads. Count out at least six wraps of tape.
Make sure the new temperature & pressure release valve is in the closed position. Reconnect the new PVC drain line to the T&P valve. Now, open a hot water faucet somewhere in the home and open the shut-off valve at the cold water inlet line. You’ll hear the heater tank start to fill.
Lift the lever on the temperature & pressure release valve. When you have a steady stream of water from the T&P drain line close the valve. When you have a steady stream of water from the hot water faucet, turn the faucet off. Turn the power back on at the circuit breaker.
For gas heaters, turn the gas supply back on. You may need to relight your pilot per the instructions in your use and care manual. Then give the water heater a few minutes to recover. Check the T&P valve one more time to make sure it’s tight.
Congratulations! You’ve made an important repair that assures longer life and greater safety for your water heater.