I know, I have written about this before. But it seems that I see poorly installed temperature pressure relief valves and their drains so often that it is obviously a concern that needs to be front and center. In older homes the valve or drain is installed wrong at least thirty percent of the time in inspections that I do. There are lots of things that can be wrong: No TPR valve, just a plug (the worst); A TPR valve that shoots straight out with no drain at all; A TPR valve with the drain made of the wrong type of plastic, such as electrical conduit or PVC which are not made for hot water; A TPR that, should it go off, will drain into the crawl space; and the most commonm -- a TPR drain that is routed up through a lack of plumbing knowledge or the use of flex tubing. The photo below is an example of that. People think, well it is just steam so it will work routed up. Wrong. The valve may go off in other situations than releasing steam. In fact it should. The idea of it is to release water if pressure builds for any reason so steam does not build up. As this water drains out the TPR valve, it will settle at the low spot in the drain. Over time, this can lead to premature failure of the valve. If that happens, and this valve ends up frozen shut, that is when the real fireworks begin. The most common reason for this plumbing error, is that an old taller water heater was removed and a shorter one put in. So the installer, not a licensed plumber who would not do that, just makes sure the pipes fit, regardless of how they are routed. Even the average handyman or handywoman does not seem to realize that, in connecting the TPR drain so it goes up, he or she is in essence working on elementary rocket science. Up, Up and Away. I just cannot get past those top 40 tunes today, even if 40 years elapsed between them.
Thanks for the interest.
Steven L. Smith
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