1/2" pipe on 3/4" water heater temp press relief valve

Apr 12, 2007 11 Replies

Greetings,



Today I looked at a house and when I asked about the 1/2" pipe on 3/4" water heater temp / pressure relief valve. I was told that it wasn't a problem since a 1/2" cold water pipe was adapted onto the 3/4" entrance to the water heater. Is this true? If not can you site anything which says this is not OK?



Thanks!



On Apr 12, 6:08=EF=BF=BDpm, " snipped-for-privacy@wdeans.com" wro= te:

functionallyt it likely doesnt matter, but code requires the line not be downsized............

On Apr 12, 6:08=EF=BF=BDpm, " snipped-for-privacy@wdeans.com" wro= te:

get a home inspector in there, if they are fudging this no doubt more corners were cut and you have a excellent opportunity to run the price down

Its really going to depend upon the prevailing code. Where my son lives, its a requirement that it not be restricted; where I live (12 miles away), its not listed in the code. He needs a drain pan under the heater, I don't (but there's one there anyway).

As a practical matter, I doubt it would make any difference at all. OTOH, codes usually specify there be no restrictions or size reductions of safety devices. Not a big deal either way, IMO, but I'm not buying the house. Would I change it? Probably not.

Man if that's all that's wrong with the house...you are one lucky potential buyer. If you were to try a leverage that against the price, as a seller I don't think that would be a barganing point. For $5.63 it would be corrected, you might be better off looking for bigger things that may not be quite so obvious. Worse case you could ask the seller to toss in a 1 year warranty if it's not already included.

Unless that 1/2" pipe runs a loooong distance it leads one to wonder why anyone would downsize it. The cost of the reducer would negate and savings in the cost of the correct size pipe.

Harry K

It's more for over temp relief then pressure relief, so does it really have to match the capacity of the input to the water heater?

Greetings,

The house only has a 1/2" water service entering the house. All the pipe within the house (except for the boiler) is 1/2" copper. I am sure they did it because (as someone else suggested) they only had

1/2" copper on hand at the time or because, believe it or not, copper is expensive enough to where a 3/4" male threaded to 1/2" copper sweat joint, 1/2" copper elbow, and six feet of 1/2" copper pipe is a few dollars cheaper than a 3/4" male threaded to 3/4" sweat joint, 3/4" elbow, and six feet of 3/4" copper pipe.

Thank you all for your time, William Deans

You have them over the barrel. Demand they knock 40% off the sale price and if they refuse, sue the bastards.

It's not a big deal. Four feet of ¾" tubing and another sweat male adapter would cost less than a meal at McDonalds or Subway.

Bill

As others have said, from a safety standpoint, this is a non issue. A local code however might require it to be 3/4". If it were mine, I wouldn't change it unless I had to to get a CO, etc. Even a 1/2" outlet within a couple seconds is going to let the small amount of water out that it takes to relieve an over pressure situation. That means it can't blow up. And if it's over temp that trips it, water flowing through a 1/2 pipe is going to be more than enough flow to bring the temp down as well, though it will take more water and longer to get that done than if it trips because of pressure.

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