Pex For Water Heater Relief Valve Piping?

Old 12-09-07, 05:03 PM
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Pex For Water Heater Relief Valve Piping?

Is it okay (code) to use 3/4" PEX FOR WATER HEATER RELIEF VALVE PIPING?

Thanks for your help!
Old 12-09-07, 08:12 PM
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3/4 PEX would not be adequate, as the ID is too small, due to wall thickness of the tubing. I can't say for sure what an inspector would say. Uncharted territory. But the code has language to the effect that the discharge from the Tp must continue undiminished in size all the way to the outlet, outside the building. On the one hand, you could argue that 3/4 is 3/4, no matter what the pipe. But we all know there are specific sizing issues in places like tub spouts etc. where the ID of PEX is an issue.

In addition, most inspector don't want any non-metallic material connecte directly to the WH, for heat reasons. Like to see 18" metal transition.
Old 12-11-07, 12:17 AM
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the inside diameter of 3/4" pex is going to be just a hair smaller than 3/4" copper but the male adapter you'd need to thread into the t/p valve is going to have a much smaller i.d. i haven't looked at this specificaly but have noticed that even the houses around here plumbed in pex have the t/p lines run in copper. i do service plumbing mainly so i'm not on many new const. job sites anymore.


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