Automotive Air Conditioning Information Forum

Hi Forgive the simple question but im new to this and want to get a bottle of Oxygen Free Nitrogen for pressure testing completely new systems that I replace on classic cars and wondered how many systems I could test with a 10L bottle.

I know the answer will be approximate depending on system size but just wanted a rough idea so that I can get the correct size bottle.

You prolly mean dry nitrogen; that is what HVAC guys use in residential and commercial.
A mobile system may take anywhere from 1-3 pounds of refrigerant, or more, or less, so the real answer is who knows.
Your tank regulator gauge set for the N2 will show the pressure in the tank and the other gauge shows the pressure you have dialed in, so when the tank gauge is getting low, time to get another bottle.

We assume you are gonna use a small amount of 134 in the system at the same time to act as a trace gas so that your sniffer can find leaks

Y'all must do one heck of a lot of AC work........

Back of the envelope calculations:

You can pressure test a front only vehicle with 150 psig nitrogen 55 times with a 10 Liter bottle which is 2500 psig when full. Leak testing is never a one and done kind of deal, might be pressurizing 10 times until you've got it tight

Thank-you I just wanted an idea of how many tests, thats great I will order a 10L bottle as that will last me ages based on installing 2-3 systems a year.