Connecting PVC to brass on water heater


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Old 01-11-19, 07:08 PM
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Connecting PVC to brass on water heater

I installed a water heater a few weeks ago. I am now getting around to finishing up a minor detail- putting a pipe on the pressure release valve. I bought a 3/4" pvc pipe and male to 3/4" fitting. I thought this would be easier than sweating more copper.

My questions are:
-Is this okay? Is there any benefit to a copper pipe there?
-How do I connect the PVC to brass? I am thinking Teflon tape, but am not sure.
 
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Old 01-11-19, 07:27 PM
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I have always used copper for the relief valve line. PVC is not rated for high heat.
You would need to use CPVC and I'm not sure if I'd recommend it either.
 
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Old 01-11-19, 11:12 PM
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You can buy a pre-fab relief drop at HD or online. Google 'water heater relief drop pipe'
 
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Old 01-12-19, 08:28 AM
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-How do I connect the PVC to brass? I am thinking Teflon tape, but am not sure.

PJ has a point, when piping hot water systems you must use CPVC pipe and not PVC pipe, but this isn't a pipe that normally carries water. I have seen CPVC used on pressure relief valves before, but I have no idea if that is code compliant or not, I just know I wouldn't use it. Lawrosa can answer the question when he comes along. Assuming you can use PVC or CPVC pipe, I see no reason to use thread sealant of any kind, there'll never be any pressure on that fitting.
 
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Old 01-12-19, 09:10 AM
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My inspectors allow PVC for the water heater T&P line or at least they have never commented on it's use. They are more concerned that it extends close enough to the floor.
 
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Old 01-12-19, 11:49 AM
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Exclamation

Thanks. I'll just use copper. It seems like that is code where I live. I have the stuff to sweat the threaded connection. No point in doing it wrong and having to redo it when I sell the place.

Thinking practically though, my whole house has PVC drain pipe that holds the hot water from the water heater (coming through a faucet). I guess if something went really wrong, the relief valve water would be hotter than that though. In 19 years the old one never triggered.
 
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Old 01-12-19, 05:17 PM
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The reason for not using PVC is that the heat where it's connected to the valve makes the PVC brittle.
 
 

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