Pressure testing residential system containing a pressure reducing valve

[ari]

Hi,
I would like to pressure test my PEX system before use. It seems this is often done with air. I found a hose fitting with a Schrader valve and my plan was to use my bike tire pump which has a gauge on it. The system also contains a gauge, as well as a pressure reducing valve with an outlet range of 40-70 psi (inlet can take up to 200 and my incoming water pressure is around 120). I've read recommended pressure for testing to be around 120 psi. The only way I can think of to get around the pressure reducer is to pressurize the system via an opening downstream of the reducing valve. Will this damage the pressure reducing valve?
Alternative testing suggestions are also welcome.
Thanks,
Ari

 

[Terry]

Testing with air is much different than testing with water, it can be dangerous.
To find leaks, a low pressure (30-50 PSI) air test is just as effective as high pressure (150 PSI) water test. This is because the viscosity and surface tension of water is greater than that of air.

https://griswoldcontrols.com/project/pressure-testing-air-vs-water/

I remember one Winter when I had some unsoldered test caps popping off my stubouts. They are like bullets when they fly off.

 

[Sponsor]

 

[ari]

Testing with air is much different than testing with water, it can be dangerous.
To find leaks, a low pressure (30-50 PSI) air test is just as effective as high pressure (150 PSI) water test. This is because the viscosity and surface tension of water is greater than that of air.

https://griswoldcontrols.com/project/pressure-testing-air-vs-water/

I remember one Winter when unsoldered test caps were flying. They're like bullets when they fly off.

Yep that makes a lot of sense. I'll use water. Same question about bypassing the pressure reducing valve, would I risk damaging it if I were to pressurize via an opening downstream from it?

 

[Jeff H Young]

120 pounds wont hurt it. no problem

 

[Terry]

120 pounds wont hurt it. no problem

With water, but not with air.

 

[Jeff H Young]

water test is what i meant . I wouldnt recomend air test, nor expect it to harm the valve but unless I had info confirming it ok no way would I air test

 

[ari]

Thanks @Jeff H Young and @Terry. Water test it is.