Replacement for R-12
 

Edit: I meant R-22 in the title. Apologies for typing without thinking much about this question:

I'm using a new-old-stock Climate Master geothermal unit that has always leaked a little Freon. With the price of R-22 refrigerant, I was wondering about the various R-22 replacements available. Anyone have experience replacing R-22 refrigerant? I don't know what on-line literature I can trust.

Thanks in advance

Are you sure you do not mean r-12 refrigerant

Edit: I was wrong twice, and edited my original question (quite a bit late unfortunately). I was meaning R22 as in HVAC not Automotive. I didn't get out the gate very well with that question did I?

R433b is pretty close to a drop in replacement, it will require tweaking the TXV to perform its best so make sure the TXV is adjustable first.

Check out R-290, aka Propane. It's a good replacement for R-12 and R-22 (not sure why you haven't edited your original post, I'm still not clear on which one you're actually asking about). I've been running it in my home system for two years now, and aside from needing to increase fan speed due to R-290 being higher performing than the system's original refrigerant, it's been trouble free.

Please don't use straight Propane in an R12 system. The appropriate blend to replace R12 is about 40% R660a (iso-butane) and 60% R290 (propane).

In this chart OZ-12 is the 40/60 blend. Watch the pressures. Because I like a perverse mix of country units, Y axis is pressure in PSI and X axis is temperature in degrees Centigrade.

http://www.fnarfbargle.com/private/1...C2/ptchart.png

Not butane. Iso-butane.

epa.gov/sites/default/files/documents/Choosing_Right_R22_Retrofit.pdf[/url]

There are a number of approved blends that can replace R22.
many of them are a mixture of R-32, R-125, R-134a and other refrigerants.
Some include R-290 in the mix as well.


R-407a
R-407c
R-421a
R-421b
R-422a
R-422b
R-422c

R-427a
R-428a
etc etc


R-410 which is not an approved substitute is a 50/50 mix of R-32 and R-125.
R-134a is also not an approved R22 substitute

R-407F which is approved is 30% R-32 30% R-125 and 40% R-134a

So the devil is in the details of the percentage of each in the mix. Which is why when using those blends you have to charge the system with liquid not vapor to try to keep the % of each the same as what was intended.

Just to be ultra-pedantic, you can charge the system as a vapor but it must be withdrawn from the cylinder as a liquid.

R410a is not a substitute for R22. *ever*.

R22 Replacement
 

I've been using R407C in most of my retrofits. It's best to replace all of the mineral oil you can with POE (drain the compressor). I haven't had one bit of trouble with it and the pressures are very close to R22. Never had to adjust the TXV. One drawback is the most of the modern Refrigerants are getting phased out and getting very expensive. R290a is good choice as well since that is what will replace all of these "R22" systems in the near future. Please don't mess with it if that unit has a leak though - it's obviously very flammable and therefore dangerous if you don't have a tight system. I've experimented with it at home and it seems to work just fine. I've repaired newer R290a systems which are already on the market. the world is going back to Propane, Butane, Methane, Ammonia, and CO2- so we're basically full circle back 80 years.

PS - no matter what you use, fix the leak first