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How and Why to Maintain a Temperature-and-Pressure Valve

This Old House plumbing and heating expert Richard Trethewey explains the extreme importance of maintaining your water heater's temperature-and-pressure relief valve

In this video, This Old House plumbing and heating expert Richard Trethewey explains the extreme importance of maintaining your water heater's temperature-and-pressure relief valve.

Steps:

1. Regardless of the type of water heater, whenever water is heated, it expands. And the water-heating system must accommodate the expansion. Otherwise an explosion could occur.

2. Expanding water can move out the cold-water line. However, if there's a pressure-reducing valve mounted near the water main, the valve can block expansion.

3. Adding an expansion tank to the heater can accommodate a certain amount of expansion.

4. All water heaters are equipped with a thermostat that controls the water temperature.

5. If the thermostat fails and pressure builds up in the tank, the temperature-and-pressure relief valve will open and discharge built-up steam and hot water.

6. Temperature-and-pressure relief valves should always be connected to a discharge pipe that extends down to the floor.

7. Once a year, open the valve to flush out minerals and sediment.

8. Never install a plug into a temperature-and-pressure relief valve. And if you see a plug in the valve, turn off the water heater and immediately call a plumber.

9. To prevent someone from plugging the valve, install a tamperproof adapter.

10. If you see water dripping from the discharge tube, turn off the water heater and call a plumber. The temperature-and-pressure relief valve should be replaced.