A/C help

Topic: A/C help (Read 1442 times) previous topic - next topic

A/C help

August 21, 2009, 01:02:39 AM

I'm not a dummy when it comes to A/C work, but had an interesting thing happen the other day. I decided to try Freeze12 on the latest acquisition ('86 Canyon Red T-Bird) to see if I could get the A/C going again. It's August in Alabama, and you ain't seen hot like 95 degrees with 99.5% humidity. For $30, it was worth a try, but think I found a much bigger problem. Freeze12 is advertized to be compatible with R-12 systems, and mix with it just fine. Says so right on the can, and even states there is no reason to evacuate if there is still residual pressure in the system. Checked that, yep, there was. Not much, but certainly enough to keep moisture from entering the system.

I put the first can in, and the clutch cycled a few times while the compressor was sucking it in, probably due to back-feed to the pressure switch at the low side of the evaporator. I put a second can in, same result. After each can was empty, clutch quit cycling, and I figured still not enough. So, I put a 3rd in, thinking the whole time, this is a LOT of freon. I should be able to HEAR a leak if that much is coming back out. When about 1/2 the 3rd can was in, the pressure relief on the high side of the compressor spit at me. Sounded more like a cat sneezing, actually.

Am I wrong, or is it safe to assume that the orifice is blocked, and I'm looking at a total revamp of the A/C? If so, I may as well convert to 134a so I don't have to worry about future re-charges. I'm just hoping I didn't damage either the compressor or the condenser with the high pressure. What all can I expect to replace on this thing, and is it a job better left to a pro?

Any takers?

A/C help

Reply #1 – August 21, 2009, 01:20:33 AM

easy fix. change out your accumulator and liquid line (orfice is in the liquid line) and things should be good. be sure to pull a vacuum and use new o-rings and oil the o-rings before putting the lines together.

A/C help

Reply #2 – August 21, 2009, 01:30:08 AM

Sounds like something is blocked up. Also how well is the fan working if your now moving enough air across the condenser when sitting still that can cause high pressure fast. Then also freeze 12 tells you to use less amount than R12. It could be that the Orifice tube is blocked up. If it was me I would pull the whole system apart and flush everything. Replace all O ring's and seals. Then pressure test the system before you vac it down. Kind double checks for leaks that way. Then go back to putting what you want in there. I've seen freeze12 used a lot with no problems. R134a works but with then older r12 condenser it isn't near what R12 does or what I have seen the freeze12 do in the same system R134a do py in. I plan on converting over to freeze 12 myself. As far as taking it to a pro maybe find someone local that can help you or do everything you can yourself and let the pro finish it off if you are that concerned with it. My home R134a job has been working great for 4+yrs now. I do have a buddy that is certified and he did the nitrogen pressure test and Vac'ed it down for me. Then let me use his gauges to filler her up with him giving me pointers along the way. I pull it all apart replaced all the seals and flushed everything. Before that I had one shop that would Vac a car down for me for $30.

Stuckman

P.s They make a kit to install a new orifice tube in your existing line. You have to cut out the section with the old orifice and install a new section with new orifice. This is easy as they give you compression unions to put it back together. This would also be the time to consider installing a auto adjusting orifice tube it makes those non R12 refrigerants work better in an r12 system.

A/C help

Reply #3 – August 21, 2009, 02:26:28 AM

I never got to the point of finding out how well it worked. For that matter, never got to the point of it working at all. I see a new accumulator and liquid hose in my future. Compressor sounded just fine when it ran. No rattling or grumbling, and seem to turn easily when the clutch picked up. As soon as it came on, though, the LP switch would drop it right back out. That's a good indication the compressor's pumping, and the blow-off is a good sign it's developing good pressure. Now to just get the freon circulating in the system .....

A/C help

Reply #4 – August 21, 2009, 09:08:31 AM

What were your pressure readings?

Shiny Side Up!
Bill

A/C help

Reply #5 – August 22, 2009, 12:06:58 AM

Didn't have gauges. I was just using a hit/miss approach, and was going to stop adding when the clutch quit cycling and stayed engaged. That ain't exactly the right way to do it, but works until I can get gauges to put on it and "tune" the system.