Re: [AMC-List] AC installing - R-12 to R-134a conversions

[<francis.swygert@xxxxxxxxxxxxxxxxxx>]

"SNIP
you can't just empty the r12 and recharge with r134, SNIP Sonofagun, I
did not know that! 'Cause that is exactly what I do! Well actually about
4 years ago that was the urban legend involved as freon started to
disappear but in this area there are a whole lot of extremely
knowledgeable A/C guys that deal with automotive A/C quite regularly."


Around 1982, when the switch to R-134a was inevitable, most
manufacturers started using PAG instead of ester oil in all compressors,
even with R-12. I'm not sure if PAG is cheaper or they just decided to
use it because it's compatible with all refrigerants. Unless you know
for sure though, change the oil. A compressor that relies on oil in the
refrigerant will burn up with ester oil. I don't know how long it will
take, don't want to find out. 

This does not apply to the big old York compressors. They have a
separate oil reservoir in the crank case and don't rely on oil in the
refrigerant for lubrication -- IIRC. There is a replacement seal kit for
them, as some of the older o-rings and seals aren't compatible with
R-134a. They will slowly leak down if the seals aren't replaced. All new
seals since the late 80s are R-134a compatible, so if any work has been
done in the last 15 years or so the compressor should be good. All
remanufactured and new compressors come with compaitble oil also. 

Most swap places recommend changing the dryer when you swap also because
it will contain some of the old oil. Not a bad idea, especially if the
driers old anyway, but there shouldn't be enough oil left in there to
make much of a difference. If ester oil is in the dryer the R-134a won't
pull it out and circulate it. The only thing it could do is reduce the
amount of oil or refrigerant slightly as far as I can tell. Ester and
PAG won't mix, but there are no adverse effects with mixing.

_______________________________________________
AMC-List mailing list
AMC-List@xxxxxxxxxxxx
http://www.amc-list.com/mailman/listinfo/amc-list

or go to http://www.amc-list.com