T&P valve installation?

[Nate Nagel]

Can someone point me to the actual code governing installation of a T&P valve on a hot water heater? Mine just crapped out on me; I came home to a lovely few inches of water on the basement floor. Appears to have done a decent job of loosening the old vinyl floor tiles anyway (silver lining) I seem to have bad luck with plumbing; I need to invest in a better dehumidifier :(

Anyway, the reason I am asking re: code is that I don't have a floor drain (obviously) and yet the water heater's T&P valve was just plumbed with a piece of 3/4" copper straight down to the floor. I'd like to plumb it over to the deep sink, however I cannot do that while following all the instructions on the package (outlet mounted straight down but only four elbows) wondering if I could upsize the pipe to 1" to allow for an extra elbow or two. Right now I have it running into the deep sink through a garden hose which I know doesn't meet code but will at least keep the floor from getting wet again while I dial in the thermostat (shut it off all the way to drain the system down while I ran to the Despot to pick up a new valve)

Right about now is where I regret following my gut; when we looked at the house the T&P valve started going flaky and the PO's called a plumber, he said just to cycle it occasionally to keep lime etc. from building up on it and it should be fine. I thought about replacing it but didn't. Hindsight, etc. (although I was a little concerned breaking it loose from the tank; had to use two pipe wrenches as one seemed two scary due to the force I was using/bending moment...)

thanks much

nate

[Pete C.]

City water? Backflow preventer? No expansion tank? T&P valve have a history of dumping a little water regularly? If so install an expansion tank on the system and you'll eliminate that problem. There should never be any issue of "lime, etc. buildup" if the system is working properly. If there is a backflow preventer on the system and no expansion tank, every time a batch of cold water gets in the tank and is heated with the rest of the system shut off, the pressure will spike up to the point the T&P valve has to dump.

[trader4]

Well, if there should never be any issue, what then accounts for so many of them failing, like when you cycle them and then they fail to close? To say there should never be an issue if it's working properly is like saying there should never be a problem with my cars engine as long as it's working properly.

Yes, but that would result in a small amount of water fairly regularly being discharged and noticed, not a sudden big dump with inchs of water on the floor that he has.

[Nate Nagel]

yes

not that I am aware of

no

somewhat - but I think the old one was weak to begin with.

I can believe that, but it should just make a little puddle and then reclose. The old one is full of minerals, obviously it just popped off and didn't reseal correctly. I cranked the water up to 130 degrees at the deep sink faucet and enjoyed a truly hot shower this AM, (which I could never do before, at anything over 120 degrees it would pop off fairly regularly) but didn't see any water out of the new valve, so I think that was the problem all along.

I'd still like an answer to my original question, as I'd prefer to pipe the T&P drain to the sink no matter what.

nate

[Abe]

The code will vary depending on where you live.

Google for building code online (your state). That should get you started.

[Pete C.]

A T&P valve is like the valve on a fire extinguisher, it should never be operated except in the emergency situation it's designed for. Once it's been operated, then you can get the crud buildup that keeps it from sealing properly. It's not something that should be tested and once it's operated, it should be serviced or replaced.

Right, but recall he mentioned the T&P was getting hinky when he was buying the place the the PO replaced it. Sounds to me like possibly the issue I mentioned, which would lead the the gradual failure of the T&P and eventual sticking open from crud buildup. If this is the case and he simply replaces the T&P, it will likely fail again in a year or two of periodic pressure discharges.

[Pete C.]

I don't have any plumbing code references to confirm any requirements for the T&P discharge piping. Logically I don't see a problem with a suitably sized piping run that open ends at the sink location.

[<kjpro]

They&#39;re supposed to be operated once a year.

[<kjpro]

I don&#39;t know why you would try and install a water heater when you don&#39;t know the required codes that pertain to a safety device. But, I&#39;d recommend that you have someone access the situation before you proceed. I could tell you the answer, but what says you don&#39;t do something else that&#39;s not up to code? There are to many codes governing P/T valves, you should have someone qualified to pipe your system. It&#39;s for your own protection.

[Bob F]

T - temperature P - pressure

If either goes too high, the valve will open. If you don&#39;t have a regulator or backflow preventer where the water comes into the house, The pressure can&#39;t go higher than the supply. Is that very high pressure? If not, pressure is not the problem. If you do have a regulator or backflow device, then you need an expansion tank to prevent releases.

Watch for releases after a long shower when no other water is used in the house while the water re-heats. If you have a backflow preventer and no expansion tank, that is when it will more likely discharge.

Temperature increases can also cause discharge. Any sign of excessive temp?

Bob

[Clark]

wrote in news:2380a$471a42fe$9440c41e$ [e-mail]:

[snip]

Once again kj shows his ignorance and tries to play it as a strength. He claims to know the code (without knowing the OP&#39;s locality!) while he is actually unable to help.

OBTW, why would you suggest that someone "access" the situation? Just can&#39;t get anything correct can you kj?

(now watch the monkey boi dance)

[trader4]

Yes, I&#39;ve seen the advice from many sources, including WH manufacturers, that the valve should be cycled once a year to make sure it will open and is not binding, etc. And I don&#39;t understand by what mechanism occasionally opening a valve is going to cause it to develop a leak. I think if it turns out it doesn&#39;t reclose completely, that means it&#39;s bad and identified the problem, but didn&#39;t cause it.

[jim]

In 25 yrs of plumbing only seen two reasons for failure temp to high or pressure which is not usual most of the time people run the tank to high and as it gets older the valve weakens cuasing it to fail or open which it should code is standard as you described in the begining. the discharge has to be lower than the valve. 4 elbows max and you can but don&#39;t have to operate it once a year. How old is the tank elec or gas and what temp is it set fore this should under normal condition never release

[Nate Nagel]

I&#39;m not installing a water heater. I replaced the old T&P valve and want to plumb it properly, unlike whoever installed the water heater.

I guess you must be a plumber since you seem to want me to pay big bucks to have someone else do something I could easily do it myself, instead of simply giving me a pointer to the pertinent section of code?

Bet it drives you nuts when people do their own electrical work, too.

nate

[Nate Nagel]

I do not see a backflow preventer, but the actual point where the water enters the house is hidden behind a closet for a couple feet so it might be in there. I don&#39;t know that I&#39;ve ever seen one (grew up in a house with well water) how large is it and what would it look like? I do not have an expansion tank. I don&#39;t have any issues with excessive temperature. I did not notice any discharge after my shower this AM which was the first one I took after replacing the valve; I had seen it weep before when trying to raise the WH temp to ensure enough hot water (I eventually set it a little lower than I wanted to) and I assume that that is what happened and it never reseated properly.

nate

[Nate Nagel]

tank is about 18 years old and it is currently set at 130 degrees - was about 120 before. I simply can&#39;t do it with only four elbows, can I upsize the pipe to 1" or larger to compensate? There is no closer drain than the deep sink, and I need to go around a corner to get there.

nate

[M Q]

You might want to look in a local public library for the building codes. Unfortunately, most building codes are copyrighted works and are not available for free on the internet.

If you are right about the code, and can not legally get the outlet to your sink, how about bringing the drain to the water heater? Add another drain plumbed to a tee with the sink&#39;s drain.

[<kjpro]

news:2380a$471a42fe$9440c41e$ [e-mail]:

International Code, Dickwad. Nuff said.

[<kjpro]

Nope, it takes longer to rip out the incorrect shit and run the correct materials. That means more money in my pocket.

[Nate Nagel]

The way I understand it, you can&#39;t plumb it straight into the drain, there needs to be a 6" air gap therefore the drain needs a P-trap, thus causing that whole idea to become waaaay more complicated than it initially sounds.

nate