HVAC people, what's compatible with R-12? Is R-22?

[Zenmervolt]

I've got a friend who does home/business/commercial HVAC work who assures me that R-22 is a drop-in replacement for R-12 and that switching my R-12 based A/C over to R-22 will not require any modifications to the system. I've looked into the matter of different refridgerants and what he's saying seems to be true. At the very least the data I've looked at suggest that R-22 is compatible with the same seals that are used in an R-12 system. Other research on my car's A/C system has shown that only the drier needs to be changed if I were to switch over to the more-common R-134a. I do not want to go to R-134a because R-134a requires a larger compressor for the same cooling abilities and there is no room to fit a larger compressor, not to mention that I don't care to spend money on a larger compressor that's not OE., plus the hassle of trying to mount a larger compressor. Since it seems to me that R-22 is almost as cheap as R-134a and R-22 won't require costly modifications to my A/C that will only reduce the systems effectiveness.

Anyone here know if R-22 will work as well as my friend says? Are there other refridgerants that are direct replacements for R-12 and will work better than R-134a?

ZV

 

Zem;

Trust me on this, replace the receiver/drier, remove the compressor and drain all the old oil out, evacuate the system, charge with PAG oil, then charge it with R-134a.

I have done hundreds of these conversions, the loss in cooling ability is barely noticeable.

 

[Zenmervolt]

Originally posted by: Roger
Zem;

Trust me on this, replace the receiver/drier, remove the compressor and drain all the old oil out, evacuate the system, charge with PAG oil, then charge it with R-134a.

I have done hundreds of these conversions, the loss in cooling ability is barely noticeable.

Made a helluva lot of difference to my Accord when I switched to R-134a. It went from being the greatest A/C ever to being average at best. Might have just been a quirk of the system, or something to do with the rebuilt condensor that was installed in my Accord at the same time (old condensor puked and I lost all my R-12, which is why I converted), but it has left me very prejudiced against R-134a. Also, most HVAC guys I've talked with hate R-134a with a passion. I've asked a bunch of HVAC people what would happen if someone filled an R-134a system with R-12 (neglecting compatiblity issues) and the universal response has been, "The system would cool better and last longer."

I've looked at the speck for both R-134a and R-12 and you're right that there does not appear to be much of a difference as far as temperatures at pressures.

I'll probably go the R-134a route just because other routes seem to be, shall we say, "unsupported" by regulatory agencies. That and R-22 is scheduled for a 90% production cut in 2015 and a complete phase-out by 2030.

ZV

EDIT: I know that it doesn't seem like it since I haven't been exactly following your advice lately (concerning this and the 924S) but I really do respect and value your opinion. I blame it on my being an impulsive young punk kid. 😛

 

Zem;
It is imperative that you replace the receiver/dryer and empty the old R-12 oil out of the compressor as well as evacuate the system with a vacuum pump, also you must remember to fill the system with R-134a to only 85% of the R-12 capacity, if you fill the system with the same amount as the R-12, your system will not cool as effectively.

 

[Zenmervolt]

Originally posted by: Roger
Zem;
It is imperative that you replace the receiver/dryer and empty the old R-12 oil out of the compressor as well as evacuate the system with a vacuum pump, also you must remember to fill the system with R-134a to only 85% of the R-12 capacity, if you fill the system with the same amount as the R-12, your system will not cool as effectively.

Yeah, I know that the system has to be vacuumed out and the drier replaced, along with changing the oil if/when I go to R-134a. That's why I was hoping to find a drop-in replacement. 🙂 I didn't know to use less R-134a though. I suppose that I would have concluded that eventually since R-134a tends to be higher-pressure than R-12 for a given volume.

ZV