Pressure Relief Valve Discharge Routing

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Hambone8780

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Hi Folks - Any suggestions on how to route the discharge of a PRV in new construction under UPC 2015 in Washington? This will be for the hydronic radiant flooring system. I'm having trouble turning the code requirements into, "what is typically done."
This is on the first floor of a building with a crawlspace. A floor drain will require an automate primer, and it's a vacation place, so I'd probably need a timer based system. Running pipe out the side of the rim boards seems like the simplest thing to do, but won't that kill my building tightness with the air gap? What would you do in your place?
Cheers!
 

Jeff H Young

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I run it to outside between 6 and 24 inches above surounding ground. I dont know what rim boards or air gaps , or building tightness you are talking about 3/4 inch pipe getting cold outside and making the inside cold? you might have factors due to cold weather or snow covering the outlet our northern freinds might know
 

Hambone8780

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Yep, we're doing a wall hung electrical boiler.
If I'm reading the code right, I need to run through an air gap in the pipe running outside. Am I overcomplicating things?
 

Jeff H Young

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typicaly its a 3/4 pipe directly connected to relief valve with end outside 6 to 24 inches above ground your air gap will be 6 to 24 inches maybe you have some other idea or you are connecting it to some other drain in which case a air gap comes into play
 

Tuttles Revenge

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What is "typically done" is as you described and is best practice. The relief is run by gravity to the exterior so that it will come out somewhere above grade.

I would run it in CPVC so that its not as large of a thermal bridge from the exterior cold. The fact that the pipe is connected to a closed valve at the boiler prevents air movement.
 

Jeff H Young

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What is "typically done" is as you described and is best practice. The relief is run by gravity to the exterior so that it will come out somewhere above grade.

I would run it in CPVC so that its not as large of a thermal bridge from the exterior cold. The fact that the pipe is connected to a closed valve at the boiler prevents air movement.
wouldnt hurt to throw insulation over the copper , just depends if you want to buy pipe fittings glue the cpvc is a good insulator as well.
 

Hambone8780

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Thanks everybody! That really helps me out!
Just to make sure I follow fully, the only open portion of the relief pipe is outside. It's that correct?
Edit, Tuttles called that out plain as day.

Have a great day folks!
 
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