Where can I run my TPR valve drain pipe

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by Dave dyi, Jun 14, 2021.

  1. Dave dyi

    Dave dyi New Member

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    I just replaced my electric water heater in the indoor laundry room. The old & new WH have a top TPR valve. The WH is in a corner with the left side and back up against a wall.

    The original WH had the TPR valve drain pipe run through the wall in to the unheated garage and then through the exterior wall to the outside.

    IMG_1947.jpg

    The house is in the mountains (in California) where it freezes/snows and I read code prohibits any part of the pipe being exposed to freezing. I also do not have a floor drain.

    Can I run the pipe to my utility sink? I'm thinking no as the flood level of the sink (rim of sink ) is 34" above floor (the bottom is less than 24" from floor).

    IMG_1946.jpg

    Does code allow me to run it to a bucket underneath the sink, like this example I found?

    tpr-valve-discharge-pipe-inspect.jpg

    I would be hard pressed to squeeze in a floor drain. I've never had water freeze in the garage so maybe keep the pipe inside the garage to discharge down to the cement floor? Or is re-attaching it to the existing pipe the best option?

    Thanks in advance for any help.
     
    Last edited: Jun 15, 2021
  2. wwhitney

    wwhitney Well-Known Member

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  4. Tuttles Revenge

    Tuttles Revenge In the Trades

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    Into the utility sink with an air gap is perfectly fine. Ensure its pointed downwards at the edge of the sink and not able to point at any person.
     
  5. Jeff H Young

    Jeff H Young In the Trades

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    I'm from So CA plumbed many new homes over last 30 years dumping relief valve on garage floor was common the norm then around the 90's sometimes inspectors would give us a hard time but if they weren't calling us out we ran it to floor, today its not seen on new homes as far as I know. but if you aren't too worried about a mess on garage floor, its not carpeted or storing stuff on floor. I'd dump it on garage floor in a minute, I try to respect that code but think this is OK if the freeze is an issue
     
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  6. Tuttles Revenge

    Tuttles Revenge In the Trades

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    Isn't the picture showing the Sink right next to the water heater?
     
  7. Jeff H Young

    Jeff H Young In the Trades

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    not totally clear to me that it can dump above a sink . but code states "through an airgap into the drainage system" and drainage system is defined as piping with no mention of fixtures or sinks. Also when saying "through an airgap" that could mean through a device . because of the scalding its not the same as condensate which would be no issue at all.
    I'm thinking in janitor closets etc they must dump into sinks but can't remember doing it my self.
     
  8. Dave dyi

    Dave dyi New Member

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    Yes the sink is next to WH. The sink would be a great place to put it however as I read the code (as a dyi'er) the flood level of the sink is 34" (the rim) and the air gap must be above the flood level and the maximum height above the floor is 24" so the sink wouldn't work. I thought I could run it farther down into the sink so the end of the pipe would be within the 6"-24" height (with about 1.5" above sink bottom) but the "flood level" things seems to also make it against code.
     
  9. Tuttles Revenge

    Tuttles Revenge In the Trades

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    Discharge pipe shall discharge independently by gravity through an air gap into the drainage system (your sink) or outside of the building with the end of the pipe not exceeding 2 feet (610 mm) and not less than 6 inches (152 mm) above the ground and pointing downwards. (24-6 inches so that its not in your face and not choked by weeds)


    OR is the key word here. Run it into the sink.
     
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  10. wwhitney

    wwhitney Well-Known Member

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    As Tuttle points out, the max 24" only applies for discharging outside.

    Would be nice if there is a product that would clip on the top edge of a utility sink like that and provide the required air gap, no idea.

    Cheers, Wayne
     
  11. Dave dyi

    Dave dyi New Member

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    Well that will make my life much easier. Just want to clarify, So should I stop the downward pipe just above or at the sink rim level or should I go further down in to the sink to meet the requirements of; "Equal to the size of the valve outlet and shall discharge full size to the flood level of the area receiving the discharge and pointing down."
     
  12. Jeff H Young

    Jeff H Young In the Trades

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  13. Tuttles Revenge

    Tuttles Revenge In the Trades

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    A T&P is connected directly to the water heater, therefore its connected directly to your drinking water. That drain when dumping into a sink is dumping into the sewer system. If the sink were to back up with sewage the drain of the t&p needs to not be immersed in the flood level. Therefore the T&P needs to have an airgap to prevent cross contamination.
     
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  14. Jeff H Young

    Jeff H Young In the Trades

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    dave diy, I didnt see your pic of w/h next to sink what could be easier? You got it easy. from a personal view that water heater pan is of little use. Im not in mountains but dont like indoor water heaters. a flood waiting to happen every 10 years (if your lucky) you got another leaker.
    In anycase the tand p to the sink a good option and concider protection from water damage , there are monitors, alarms , shut down valves pans with drains to outside, or relocate the tank out the house. kind of a thoughtless build where does t and p go now ? just a valve on tank with zero piping ? I see that all the time
     
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  15. Tuttles Revenge

    Tuttles Revenge In the Trades

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    We install water heaters with Floodstop valves and alarms in the pan pretty much on all our remodels. Its the slow leaking water heater that does a lot of damage.
     
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  16. Dave dyi

    Dave dyi New Member

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    Jeff, you're right about the thoughtless build (from 1979). I just got around to replacing the WH that was here when I bought the place and am lucky it didn't fail in many ways. The WH was sitting on a cinder block and I always wondered why someone would do that. Found out when I replaced it- the conduit was too short (not the wires just the conduit) so some moron put it up on the block rather than just replacing the conduit. There is no laundry room floor drain. There was no pan under the WH and there was no TPR valve drain pipe, just the valve.

    I think I can run a pvc drain pipe from the pan to the outside but that would allow cold air in to the house as well as bugs. I need to find some sort of flap or one way valve that doesn't rely on backpressure just gravity to close (and would open with the minimal flow that would come from a slow leaking WH.)
     
  17. Dave dyi

    Dave dyi New Member

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    Thank you for your help!
     
  18. Tuttles Revenge

    Tuttles Revenge In the Trades

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    Run the T&P to the sink! Its right there!
     
  19. Dave dyi

    Dave dyi New Member

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    Yes, I ran the T&P to the sink as you said, Thank you again Tuttle.

    I was talking about trying to run a WH pan drain pipe to the outside (there wasn't a pan under the old WH, so no drain pipe and no floor drain) Just trying to figure out what to use on the end of the outside pipe that will open with the minimum water flow if WH starts to leak but stays closed/sealed without backpressure since there won't be any. Otherwise it's just open from the outside to the drain pan for cold air & bugs to enter the house.

    I know IPC 504.7.2 says I don't need a pan drain if not previously installed but if I can figure out what to put on the end of the pipe, it's a cheap addition to avoid water damage.

    Odd that code says T&P drain pipe has to be protected from freezing but I didn't see the same thing about the pan drain (unless I missed it which is totally possible.)
     
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  20. Tuttles Revenge

    Tuttles Revenge In the Trades

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    HEH.. must have missed that transition!

    I install floodstops on our water heaters with an audible alarm both with detectors in the pan.
     
  21. Jeff H Young

    Jeff H Young In the Trades

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    I thought we were in CA? UPC code ? UPC code requires pan even if it never had one
     
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