Well, I'm learning about how to service automotive AC units. Buying the needed equipment. Manifold pressure gauges were pretty cheap, and a vacuum pump too. But I still need to get a recovery tank (pretty cheap) and a refrigerant recovery machine (holy cow!). I did find a relatively cheap used refrigerant recovery tank on Evil-Bay but am waiting to get a replacement credit card as somebody got my number and I had to cancel my card. I'm not liable for any of the fraudulent charges, but what a pain. Anyway, a/c stuff is pretty interesting.
What prompted this was constant problems with my TR a/c. Last summer I had a lot of the system replaced. It would freeze you out after that. But then, over a month ago it stopped blowing cold, so I made an appointment with my mechanic... for almost 2 months later. This is pretty frustrating, as it's been REALLY hot and humid. I did do a simple can-and-hose recharge, and the a/c started blowing a little bit cooler, but won't blow air colder than 60 degrees, even on a cool (75 degree) day. So I bought the manifold pressure gauges and the a/c vacuum. Ran a vacuum test and it pulled down as required on both sides and held it for 30 minutes, so that indicates no leak. But where did my r134a go? I was able to add a can without overcharging.. . hmmm. So I ran a static pressure test, which should show about equal amounts of pressure on both high and low sides, and it did--82 and 82 +/- 1. So I started the car up and ran an operational pressure test. Both sides were somewhat low, with enough pressure on the low side (cycling between 20 and 35psi) to kick the compressor on -- plus the compressor was cycling on and off every few seconds, indicating a low charge. High side was 140 cycling to 160--which is apparently low for the high side. So I cracked open another can and added about half of it to the system through the manifold pressure gauge set rather than the old single-tube-to-the-low-side. Pressures went up a little on both sides (low 24 +/- 2 to 38 and high 190 to 230) until the compressor stopped cycling so often and stayed on for long periods of time. All well and good, but it still won't blow air colder than 60 degrees. I haven't tried running water over the condenser. If the condenser is not exchanging heat well, that will help it, or so they say on YouTube. At first I thought the orifice tube was somewhat clogged because it had been a problem in the past. But those pressure reading aren't the symptoms of a clogged orifice tube. But that's why I asked where it was. Only a few more days until my appointment, at last! I'll let the pro figure it out this time. I'm still learning.
