PEX air pressure test

[Martin Canada]

Hello all,

I am just about to put my drywall up and want to make sure my PEX water supply lines are good to go. I have a hot and a cold 3/4" main line going to a manifold reducing down to 1/2". I looped at the shower lines (shower valve not installed) and capped the rest. I put the pressure at 80PSI and loose about 5-6PSI over 3 hours. I did re-crimp all the fittings and went around with soap water ( no bubbles to be seen). Now I wonder if the 5-6PSI drop over 3 hours is acceptable and due to expanding lines, air temperature from compressed air, change in outside temperature? Any ideas and input would be really appreciated since I want to be confident in the system before I cover everything with drywall.

Thank you so much

 

[Weekend Handyman]

I am not a plumber. Not sure about the pressure drop, but it seems high. However, you are not supposed to double crimp your fittings.

 

[Sponsor]

 

[Martin Canada]

I am not a plumber. Not sure about the pressure drop, but it seems high. However, you are not supposed to double crimp your fittings.

i only crimped the existing crimps again

 

[Weekend Handyman]

i only crimped the existing crimps again

Ya … I know … Many manufacturers say not to do that.

 

[Martin Canada]

Ya … I know … Many manufacturers say not to do that.

interesting. good to know

 

[Reach4]

The old Uponor link doesn't work any more. The jist is to apply extra air pressure for a period (hours??). Then back off to the test pressure, and watch for a drop from there. The PEX will slowly expand when first pressurized, so the pressure drops. By pre-stretching the pex, the test can proceed.

 

[Martin Canada]

The old Uponor link doesn't work any more. The jist is to apply extra air pressure for a period (hours??). Then back off to the test pressure, and watch for a drop from there. The PEX will slowly expand when first pressurized, so the pressure drops. By pre-stretching the pex, the test can proceed.

I have read about the pre stretching. My compressor only gets it up to 80psi. So maybe do a pre stretch to 80psi and than drop it down to 60psi and see how long it holds?

 

[John Gayewski]

1.5 times the supply pressure for 15 min. Using a gauge that who's max is roughly one third larger than 1.5 the supply pressure. Longer tests just make for pulling your hair out unless your accounting for temp changes.


If your supply pressure is 60 psi then the test pressure should be 90 psi with a gauge that reads to 120 (roughly two thirds of the gauge is 90) this keeps the gauge increments small enough to read a drop over 15 min.

 

[Martin Canada]

Holding 100psi over hours. the pressure gauge my buddy gave me was failing. Built a new one and all good. Thanks for the input. If you ever have troubles with your test start with switching the gauge. Would have saved me lots of stress and time.