Recommended steps for pressure (air) testing PEX

[Mikieboyblue]

Hi pros, what is your recommendation for pressure testing PEX supply lines?

For example:

Before connecting the water heater?
Create a temporary loop of hot and cold lines to test it all?
Before connecting shower valve?
Test to 100psi?
Leave pressurized for 24 hours?

Huge thanks in advance!

Y'all are awesome.

 

[Geofd]

Should check your local code I believe in mass it's 125 psi for 24 hours. Test them seperately, with 2 gauges

 

[Mikieboyblue]

Should check your local code I believe in mass it's 125 psi for 24 hours. Test them seperately, with 2 gauges

Code here is 100psi water or air for 15 minutes. If repair existing lines, then the psi is the normal operating psi (60 in my case). Was curious if folks mostly stick to the 15 minutes were permitted or let go long (overnight, so on).

I can use the main fill gauge and put a pressure test gauge on the hose bib too with the valve open. But was originally planning on only one gauge.

Edit: Strike the above paragraph. I now understand what you meant -- test hot and cold separately as opposed to making a temp loop. I only have one gauge with a fill stem so I'll test one at a time. But this works well since I can use the not yet connected 3/4 that would go to the water heater as the fill location.

 

[Twowaxhack]

You can jumper hose it at the washing machine box. Just a common washing machine hose works.

I never use just air, I like to fill it full of water first. It’s a little safer that way.

I like to test for an hour.

 

[havasu]

Just a question.... since water is obviously thicker than air, and is unable to compress as air does, is this an approved method?

 

[Twowaxhack]

Just a question.... since water is obviously thicker than air, and is unable to compress as air does, is this an approved method?

Yes, pressure is pressure.

 

[havasu]

Thanks. I would assume you have to be pretty sure that the test would pass if you're running water initially?

 

[Twowaxhack]

Thanks. I would assume you have to be pretty sure that the test would pass if you're running water initially?

Yes, I crack the main valve and let the system fill slowly initially with water. While it’s filling I’m walking around looking and listening.
Once it’s full and no leaks for a 15 minutes or so I’ll turn the water off and connect my air compressor to whatever pressure I want to test at.

You can also use a hydrostatic test pump.