- Temperature relief valves, also know as temperature and pressure valves or T&P valves, are used to prevent the dangerous buildup of water, vapor and gas pressure inside of a hot water heater. A metal valve, typically brass or steel, is screwed into a special outlet on the side or top of the tank. The valve releases pressure, preventing the tank from leaking or exploding.
- Water heaters take cold water into a tank and heat it, either with electrically-powered heating elements or gas burners. When water is heated, the natural by-product is steam. While the water is not boiled, it is typically heated to 100 to 125 degrees. The residual steam and heat must be released to allay the threat of damage to the tank, pipe bursts or explosion. The valve taps the tank and releases any pressure. The backed up pressure pushes through the valve gate, which is tuned to open behind a prescribed level of force.
- Installation of a T&P valve is easy, if necessary. New hot water heaters come with valves installed at the factory. While T&P valves rarely need replacement, they can be installed by simply screwing the valve into the valve stem. Depending on the placement of the valve, a homeowner may want to install plumbing pipe to carry the released liquid or steam away from the tank. Using 3/4-inch CPVC plumbing fittings and some plumbing adhesive, you could create an outlet which directs the spill off away from the water heater.
