My water heater has a pressure releif valve attached to the top, with a downspout that drains on to the floor. There is a second release valve on the hot water distribution pipes, this one drains to the ground outside. what is the purpose of this second valve? Is it a code requirement?
My intuition is that is is designed to trip before the heaters release valve so water is blown off outside instead of on the basement floor. The distribution release valve is set to 125 psi, but I can't find a set point labeled on the heaters valve.
Best Answer
I have not heard of a TPR valve being required outside or further away from the water heater there would be less of a chance of valve opening for temperature the further away it was from the heater. I have seen reliefs on hydronic systems at a lower pressure to protect the embedded plumbing but not water heaters. Possibly a work around for a drain that the one at the water heater did not have.