I'm a real dummy on this issue so I've got to ask you to help me understand the purpose of the nitrogen. I understand using it to displace air, but how does it flush actual debris like compressor seal residue and sludgy oil out of the system? I've seen pictures of orfice tubes that are blocked with crud and vendors selling solvents for flushing and auto A/C guy swearing up and down that you've got to physically flush out debris <img src="/forums/images/graemlins/scared.gif" alt="" /> Does nitrogen do all that? Thanks for bearing with my ignorance. -- Matt
nitrogen wont flush out sludge/debris.
this is what we do (usually this is a compressor failure, metal dispersed into the system)
1: recover any refrigerant then leak check with compressed air @ 150psi. yea you HVAC techs may disapprove but the system has metal throughout it and imminent failure of new parts is certain in any case.
2: flush system with liquid flush provided in the ac kit we bought , after removing failed parts
3: blow out with filtered/dried compressed air (getting water out is the key here)
3: install new/reman (with new o-rings/seals as needed ):
a: compressor
b: condenser
c: expansion valve/orifice tube
4:add oil as per service manual
5:vacuum down to 24" of mercury for 1 hour or more
6:recharge system, add ac dye for leak test.
7:check for leaks
this is an automotive ac system. it is not a critical system where serious bodily injury or death will result from using compressed air.
it is not meant to for things like food storage, it is for personal comfort (only one of my six vehicles have a/c; my wifes van. it regularly hits well over 100 in the summer here; i dont even have ac in the house)). all the ones i have done using the above have worked perfectly.
as far as the compressor goes, i would replace it. then go r134a (if its not in it already). we are talking about a 18 year old a/c unit.
