Water Heater Pressure Relief Valve Pipe Size

It will permit a flow of only 13 gpm 7 gpm less than.

Water heater pressure relief valve pipe size.

Be constructed of those materials listed in section p2905 5 or materials tested rated and approved for such use in accordance with asme a112 4 1. The pipe itself needs to be either copper cpvc or galvanized water piping. If a pressure relief valve for a boiler is accidentally installed on a water heater it will leak like crazy from the start. Unscrew the overflow pipe from the tpr valve using a large adjustable wrench.

Most residential water heaters have a 3 4 threaded opening for the discharge pipe. Model codes require the t p relief valve be set no higher than 150 psi. Take the old valve to the hardware store and buy a replacement valve that matches it. The relief valve on your water heater has a pipe attached.

The discharge pipe shall terminate within 6 inches over the floor and not have any threads on the end nor are there to be any valves in it. Tpr valve shall extend into the heater tank and monitor the temperature in the top 6 inches of the heater. It s important to choose a replacement valve with the same btu rating and pipe size. Not have valves or tee fittings.

There are several styles of tpr valve available including universal pressure relief valves. Another factor in determining the pressure rating of the t p relief valve is the code itself. Since in our example the pipe size is 3 4 let s start there and see if a 3 4 valve will be the best choice. Not terminate more than 6 inches 152 mm above the floor or waste receptor.

A trapped tpr dischage pipe is a common defect when a replacement water heater s tpr valve is lower than the original one and the installer connects to the exisitng discharge piping at the wall. The tpr valve will activate if either water temperature measured in degrees fahrenheit or pressure measured in pounds per square inch psi exceed safe levels. The valve should be connected to a discharge pipe also called a drain line that runs down the length of the water heater tank. This size valve will not work.

Therefore a water heater with a mawp of 160 psi still requires a t p relief valve set at 150 psi even though the vessel is designed and built to withstand a higher pressure. These valves may look identical but they re set to go off at 30 psi. By code you have to run the same size as the opening which means the pipe needs to be 3 4 in diameter. Not have a threaded connection at the end of the piping.