I was wondering if anybody out there had any experience with R-12 AC system on a Piper Saratoga. At the top of my list for buying a new airplane was to have AC. And then a few months after purchasing, it is no longer working. It appears to me that I have there options:

1. Try to have the existing system worked on and find some R-12 refrigerant. I hear it may be available in Mexico.

2. Have the system converted to R-134 refrigerant. I have been reading that it may not work as well. I currently have an estimate for 13K for somebody to do that and can have the parts in in about two weeks.

3. Remove the AC system and install an electric air conditioning system. This would be my preferred route to go. I believe it would cost about 25K but should be a fool proof system. The downside is that Kelly Aerospace who makes the AC system does not have a STC for my airplane. I was also told that getting a field approval in California to have such a system put in would be extremely costly and very hard to do.

Any thoughts, experience, or suggestions would be greatly appreciated.

I’m not a airplane mechanic. I am a automotive A/C guy. I am not completely familiar with the Saratoga A/C system, however every single engine piston aircraft A/C system I have looked at is very similar to automotive A/C.
I maintain a A/C system in a P 210 for a friend. It works just like automotive.
My first choice would be to service your R-12 system. R-12 is around. Try Craigslist. Ask car buddies, automotive A/C shops.
The second choice is to convert to r-134. Not as difficult as we were originally told.
Basically replace the receiver/dryer, change the gauge connection fittings and evacuate and recharge. There’s a conversion formula for how much r-134 to add. $13,000 is crazy money for that.
R-12 systems converted to r-134 don’t work as well, generally, but they do work.

What Bill said. These are simple units made mostly of car parts. A lot of airplane techs don’t have experience with HVAC. Get an automotive HVAC tech to troubleshoot and repair it. Maybe have him work with your shop. There’s plenty of R12 around. No need to change it, especially not for 13k.

Robert T

I repaired a ‘98? Saratoga a/c system. It was a 134 system. Condenser took a rock impact. Guess that’s a danger when it’s only a foot off the ground, behind a big fan. Finding the leak was easy. The fix was not difficult, but was time consuming. Probably the most common place for them (a/c systems in general) to leak is the compressor shaft seal.

As said above the R12 systems are pretty simple. Basically Compressor, expansion valve, evaporator, condenser and pipes. R-12 is still pretty available (figure 25-35$/pound or <100 a charge). You need someone that understand AC. You don't say what is wrong but if the Condenser door opens and it blows air, then the next place to look is the pressures.

Converting to R134A should not be a 13k affair. The system needs to be flushed and the oil changed. A new compressor and possibly the expansion valve. You could replace all the soft lines too but it still should be well less.

First thing is to figure out your issue why it stopped working. if it is a leak, need to fix that before you go the R12 or 134a route

We had a issue on our Saratoga with the door. The door in the back of the plane on the bottom opens up to allow air to get into the condenser. We checked everything and could not figure out what was wrong. Then realized when we upgraded the panel they messed up the control for the door.

R-12 is better and available. I would not go thru the trouble to change it out.

Mike

Thank you guys for the feedback. It sounds like the way to go is keep the existing system and there really is no problem with R-12. I did fail to mention what problems I have been having. Fist, I was told on the pre buy inspection when I bought it that the compressor was leaking. But then was convinced that it was a normal thing for theses airplanes and to just re charge it every year or two. Never having an airplane with AC, I took this at face value and did not have the compressor changed. AC worked fine for a couple of months. Secondly, when the air conditioning stopped working the first time, the breaker would keep popping. I was told that there was a bad limit switch on the condenser door and had that changed. AC worked for about two weeks. Third issue, the second time it stopped, I was not able to get the condenser door to close. I was then told that the condenser door motor is bad and to replace that. But at this point, I did not have faith in the information I was being given. So I decided to start looking for other options. I was then again told by somebody else that the condenser door cannot be opening and closing because the system needs to be charged. But that didn't seem quite right to me either. The only thing that I have come to a definite conclusion on it that finding somebody who knows how to work on AC systems in airplanes is a very hard thing to come by. And that seems surprising to me being that I live in California. It's not Alaska. And it gets a little warm here sometimes.

I don’t have the drawing for your serial number in front of me, but usually the door will close with no Freon in the system, but will not open again until the low pressure switch is closed by servicing the system with refrigerant. If the switch is stuck closed, the door will continue to open and close normally regardless of system pressure. There has to be someone around who can work on it. It isn’t that complicated. Some smaller corporate planes have Freon cooling and the people riding in back expect it to work.

Hi Dean,
You should check with KSEE... There are a couple of mechanics on the field that are quite good with a/c systems. I will get you a number on Tuesday.
You should be able to repair/recharge the system.

417C. Is a direct replacement for R-12.