Hot water pressure relife valve drain pipe

[Brother]

My question is, does the hot water tank pressure relief valve pipe that goes to a leak pan underneath the hotwater tank ok to just let it go to there, or does that pan have to drain to the outside, or if not feasible for outside because of location of tank, is ok to connect to an existing drain? Would it be a code requirement?

I do not like the idea of just have the water from the pressure relief discharging onto the floor by over filling a pan. I was told you cannot run the pressure relief pipe directly/connect to a drain line because of code, it has to be free open to where it can be seen.

 

[Jadnashua]

First, that valve should never open unless there's a problem, so it would be unusual for the WH to be sitting in a pool of water. If yours does open frequently, you have another problem that needs to be resolved (typically, it would require an expansion tank). The T&P valve opens with over temperature (almost boiling) or over pressure (over 150psi). You can easily get to 150psi if you have a closed system and no expansion tank after using a lot of hot water during the reheat phase and no further hot water use.

 

[Sponsor]

 

[Gary Swart]

Here's an idea that might help if you have a floor drain. Run the discharge pipe to the floor drain. Cut a hole in the drain cover and elbow the pipe through the hole. If no floor drain, then run the pipe to the outside. You might have to get creative to do this, but keep in mind the pan will not hold the entire tank. It would take care of the T/P opening briefly which is typical where there is no expansion tank, but if the T/P fails to close, you will have a flood.

 

[Dj2]

Around here, we have the water heaters in the garage, and code says to drain the T&P valve to the outside. Older homes have the water heaters inside (closets, kitchens or hallways) and are subject to floods when the valve opens, if not drained outside.

Find out what your local code says.