Question: Hi Robert, I sent a picture to you, can you tell me what the device is that is sitting at the end of the faucet? It’s dripping and I have no idea what it does, or know if it is necessary. Any insight?
— John F.
Answer: John, that is a TNP (temperature and pressure relief) valve and yes, you do need it. If any area of plumbing pressure within your home gets too high, let’s say, for instance, near your water heater, this valve will release pressure to prevent a “blowup” or burst pipe. There is generally a TNP valve at the water heater as well, but this one is for the entirety of the home.
These devices also monitor temperature. This needs to be changed if it is leaking, a sign that the seal has failed. The gate valve below it needs to be shut off, then this TNP removed for replacement, like for like. Remember to use Teflon tape on the threads, applying in the opposite direction so that when you screw the new TNP on, the tape is not forced off in the wrong direction.
Open the gate valve back up and you should be good to go — an easy job if you are handy.
Robert Lamoureux has more than 40 years of experience as a general contractor, with separate licenses in electrical and plumbing contracting. He owns IMS Construction Inc. in Valencia. His opinions are his own, not necessarily those of The Signal. Opinions expressed in this column are not meant to replace the recommendations of a qualified contractor after that contractor has made a thorough visual inspection. Email questions to Robert at [email protected].
