Hi,

I have three evaporator cores that need to be tested for leaks.

What is a safe pressure to test an evaporator at for a automotive application. I don't want to put so much pressure as to bust the core. I've noticed that many a/c places often pressure test the whole system at 200 PSI, I don't understand why they do this when certain components don't see this pressure and could not be made to withstand it?

When testing the evaporator out of the car, Can the test be done with the TXV Valve connected?

My workshop manual for my car says the low side pressures are 30 PSI, so should that be the pressure that I should test my evaporator with?

Thankyou.

hi, actually the evaporator core reach the 100psi when the system is turned off. the pressure stabilize on the entire system once is off. an evaporator core can be tested with the valve on and I recommend that you test the evaporator with around 150psi. Sometimes when the leak is minimum the low pressure wont let you detect it. when I test an evaporator, I turn on the system for around 5 minutes, then I turn it off and wait around 4 minutes, after that I turn on the blower only, not the compressor, and check for leaks with a leak detector.