Can Pex be used for Water Heater connections?

[tankmcmanara]

Can I use Pex directly to connections on top of electric water heater? It appears Pex is rated to 200 F now and most water heaters are set at 120F. Thanks!

 

[sarg]

I installed a new heater three years ago & at the time did some research. The manufacturers I checked stated it was OK on electric & advised to follow code of 18" away on gas.
I've had no problems @ 125F.

 

[Twowaxhack]

Can I use Pex directly to connections on top of electric water heater? It appears Pex is rated to 200 F now and most water heaters are set at 120F. Thanks!

It’ll work fine but some codes will not allow it.

 

[Bird Doo Head]

It’ll work fine but some codes will not allow it.

I "temporarily" used PEX-A when installing my gas heater because I didn't have the proper brass & copper fittings & it was a night job. That was 5 years, 7 months ago.

So much for Temporary.

After reading your question, I checked the (clear) PEX-A and it has no signs of discoloration, cracking, stiffening or crazing.

With the heater heating & no water running, the surface of each pipe was between 1.5 and 3 Degrees-F above ambient 12" away. The brass PEX x M-NPT fittings into the heater are warm to the touch. (The induced draft is pulling air across them, thus there's some cooling.)

The PEX has sleeves of pipe insulation and a loose wrap of skrimmed aluminum radiant barrier (not the flammable bubble kind) around the pipes. I don't know if that helps or not.

Paul

 

[tankmcmanara]

I "temporarily" used PEX-A when installing my gas heater because I didn't have the proper brass & copper fittings & it was a night job. That was 5 years, 7 months ago.

So much for Temporary.

After reading your question, I checked the (clear) PEX-A and it has no signs of discoloration, cracking, stiffening or crazing.

With the heater heating & no water running, the surface of each pipe was between 1.5 and 3 Degrees-F above ambient 12" away. The brass PEX x M-NPT fittings into the heater are warm to the touch. (The induced draft is pulling air across them, thus there's some cooling.)

The PEX has sleeves of pipe insulation and a loose wrap of skrimmed aluminum radiant barrier (not the flammable bubble kind) around the pipes. I don't know if that helps or not.

Paul

Everyone, thanks for the feedback. And Paul, yes that helps, but I am using electric WH. I agree, what would be the actual temp difference where the pex starts at the end of a 18 inch required copper section, and right at the connection? Evidently the copper is required on gas WH because the hot exhaust tube would be nearby (probably between both pipes), and it is safer to move the Pex away from that some distance. Every thing I've read so far indicates no copper needed on electric WH.

 

[Twowaxhack]

The main problem with a gas heater would occur before the heater started drafting. The heat spills at the draft diverter and can exceed the limit of what the pipe can handle. This would vary between installs depending on length of vent run, fittings, ambient temps, etc.


With electric it’s not an issue.