Elec, Hot Water Tank P/T Drain Pipe - What Is Code - Plumbing - DIY Home Improvement | DIYChatroom

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Old 01-28-2012, 10:48 AM   #1
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Elec, hot water tank P/T drain pipe - what is code

Hi thought I remembered reading somewhere that Code requires there needs to be a drain pipe attached to the pressure/temperature safety valve to protect individuals from possible scalding water issues if P/T opens. Forgot how close to the floor the end of the pipe has to be? Thought It was something like 10 inches ? The guy that installed the electric hot water heater in our new house looked at me like I had two heads when I spoke of this as an issue when I saw he hadn't added the pipe.

Also, don't I need some distance between the tank and PEX tubing? I thought PEX could NOT be directly connected, but needed a distance of 18 inches? of copper/galvanized pipe or flex SS tubing must be used?

Can someone clarify these two issues , if in fact they are issues or not or am I am completely wrong in this.




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Old 01-28-2012, 11:09 AM   #2
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Citing Oregon code from my memory here.

No pex within 18" of the water heater.

As far as the T&P piping it has to either go outside, or into an approved receptor or on grade garage slab.

If the receptor is piped into the drainage, then you need an airgap as the t&p is technically a freshwater line. If it's going into a pan that has a drain to the outside, then give the end of the pipe enough clearance so that water can easily flow out of the end of it, but make it long enough so that it's below the rim of the pan.

If it's dumping onto the garage slab, just put it close to the floor. no big deal.

If it's piped outside of the house, there's a clearance from the ground. . . . I'm pretty sure it's between 6 and 18 inches, but i'd have to double check, and I don't have a book on me.


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Old 01-28-2012, 11:18 AM   #3
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You are going to get several answers but one thing that will probably remain constant is that the T&P needs to be piped either outside or near to the floor- no closer then 6"
As for pex- I've heard you can direct connect it to an electric heater but not gas. also heard no, in both cases.And you defiantly do not hook pex to the T&P
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Old 01-28-2012, 11:39 AM   #4
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thanks Alan, yes the hot water heater is on the second floor sitting on a pan that has a drain in it that goes down to the outside of the building on the first floor. That all looks like it was done correctly although I question the use of PVC ( maybe 1" or 1.25") to carry possibly super heated water through the house to drain it safely outside. I would have thought CPVC would bed a better choice.

I know at our home in NJ we have the tank in the basement and its drain just ends a few inches off of the floor. Sounds like this one is a possible issue also since we aren't allowed to punch a hole in the basement floor to act as a drain ( Radon gas issues in our area) so if it leaks it just floods the basement.

Guess I'll take a run to HD and get some supplies.

thanks again

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