Thermal Expansion Valve Water Heater

A dripping temperature and pressure relief t p valve on the water heater is an indicator of a potential thermal expansion problem.

Thermal expansion valve water heater. When water is heated it expands this is called thermal expansion. Installing a thermal expansion tank properly sized for the tank. The thermal expansion relief valve can replace a water heater expansion tank because it functions similarly. As plumbers know the expansion tank equalizes pressure throughout the plumbing system by providing a space for hot water to flow into.

Both products absorb the excess pressure in the plumbing system created by thermal expansion. Prevents constant high pressure fluctuations caused by thermal expansion in closed loop systems. For example water heated from 90 f to a thermostat setting of 140 f in a 40 gallon hot water heater will expand by almost one half gallon. This check valve is designed to keep water expansion from pushed back into the city water system but unless there is an expansion tank in the system the pressure has nowhere to go except to put stress on the water heater tank itself and surrounding pipes.

This is because when water is heated its density decreases and its volume expands see below. A thermal expansion valve is then in essence a safety device that will open and spill water and pressure to prevent plumbing equipment or piping damage or worse unsafe conditions. Using a governor 80 ballcock. Thermal expansion protection is required on new water heater tanks.

They are used to prevent plumbing system and or water heater damage as well as unnecessary relief valve discharge caused by excessive pressure from thermal expansion. Thermal expansion protection can be done 3 different ways. How does the expansion tank of the water heater work. Our potable water expansion tanks are designed to absorb the increased volume of water created by thermal expansion and maintain a balanced pressure throughout the potable water supply system.

In hot water supply systems thermal expansion of heated water may occur wherever potable water is heated in a closed system when the potable water is iso lated from the public water supply by a one way valve such as a pressure reducing valve backflow preventer or check valve. This is the valve with the small handle or lever that automatically opens when either the temperature or pressure inside the heater tank exceed a set limit usually 150psi 210 f. When the pressure supplied to your home is at a suitable level between 40 and 80 ps and has a prv or check valve the thermal expansion tank enters.