Thread: The Hide and Seek TPR Pipe

Found this during today's townhouse inspection. I counted seven bends in the pipes: six 90-degree bends and one about 135 or so. Had fun tracking the pipe through the floor and into the basement. I refuse to believe this was an original install... how could it have passed?!?
The TPR valve was on the side of the water heater so you can't see it in the picture. Pipe goes down and makes a turn to the left. First pic shows the pipe crossing in front of the water heater, then making two more turns to go down through the floor. Second picture shows it emerging from the subfloor and making a turn to cross under the floor joists. Third picture shows the last bend as it goes down the stud. The last picture shows the termination... in the heat pump condensate pipe.
(And yes, I did call out the PVC-to-ABS join seen in the last picture. There were several of these.)
House was built in 1982 and there were no permits issued for any remodeling work since the original construction. Gotta love the Handy Andys of the world!

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Hello............the PVC/ABS joint appears to be threaded male/female fitting, so would be OK...........Greg

Originally Posted by Gregory Booth

Hello............the PVC/ABS joint appears to be threaded male/female fitting, so would be OK...........Greg

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Sure is a lot of Purple Primer if that's the case.
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Originally Posted by Billy Stephens

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Sure is a lot of Purple Primer if that's the case.
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............I'm pretty sure she was referring to the soil line shown in the third picture--that's the only ABS I see..........Greg.

Originally Posted by Gregory Booth

Hello............the PVC/ABS joint appears to be threaded male/female fitting, so would be OK...........Greg

Maybe... but this one a few feet away sure wasn't.

write it up and move on!

I'm not sure why this would be termed "hide and seek" plumbing. Making a few turns to find the destination is normal plumbing. The transition between PVC and ABS is accomplished by using All Purpose Cement, by Oatey (#30821). It is listed for use with ABS, CPVC, PVC. Therefore, if the coupling fits the two pipe diameters, they can be properly joined. Provided the local code allows it.

I don't see in the photo, that there actually is a threaded fitting on the copper, where it joins the PVC. Even if there is a threaded copper fitting, PVC is not suitable for heated water. Also, if heated water [did] enter the PVC as situated at 90 PSI or higher, there is a possibility that the water would travel back toward the condensate pan in the Evaporator compartment. There would be a gas trap at the AC unit, so if any water went that direction, it would end up on the floor. As in any other waste pipe configuration, this joint would require a swept Tee. Those don't exist in 1/2" PVC. The way to fix this situation, would be to run the copper to the stand pipe, with a Tee for the PVC to join into the copper.

Originally Posted by Welmoed Sisson

Maybe... but this one a few feet away sure wasn't.

..........my vision must be failing-I sure can't see that in the "last picture". Why don't you confirm whether the PVCxABS connection you referenced in the "last picture" is threaded?...........Greg

Originally Posted by Gregory Booth

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PVCxABS connection you referenced in the "last picture" is threaded?...........Greg

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Yes Threaded
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Originally Posted by Welmoed Sisson

Found this during today's townhouse inspection. I counted seven bends in the pipes: six 90-degree bends and one about 135 or so.

Moderately fun fact.....In 3/4" PVC pipe, six 90 degree elbows is roughly equivalent to the friction flow loss of 27' of straight pipe.

Chart for this:
PVC - Equivalent Length Friction Loss in Fittings

P2803.6.1 Requirements for discharge pipe.
The discharge piping serving a pressure-relief valve, temperature-relief valve or combination valve shall:
2. Discharge through an air gap located in the same room as the water heater.
5. Discharge to the floor, to the pan serving the water heater or storage tank, to a waste receptor or to the outdoors.
7. Discharge to a termination point that is readily observable by the building occupants.

Once they fix those violations, the number of elbows shouldn't be a problem

Did they even bother to furnish a pan?

Mr Platt has it right. this is a code violation.