Working on R134 System - How to Update R-12 Gauges and Hoses
 

Am getting ready to service an R-134 system. I have previously worked on R-12 systems and still have gauges and hoses ... my understanding is the R134 has different size fittings and hence the hoses must have these, too.

I saw converter fittings that allow the use of R-12 hoses and gauges ... is this an OK solution for occasional use? They were about $13 apiece (low and high) ... how about the cans of R134 ... they look like they require a different connector ..

Any advice of help would be appreciated!

It is not recommended that you use R-12 guages on a R134 system. You will contaminate the guage set, specifically the hoses. Then the R-12 and R134 will be mixed and contaminated in both systems.

Dave

I second the opinion above. You really ought to purchase a 134 manifold gauge set. The cross contamination will give you fits later on down the road. My $0.02;)

You absolutely should get a new manifold, hose and adapter set for your 134 system.

There are indeed adapters and such available to switch back and forth, but the cross contamination risk is too great. When I bought my 134 set in the early nineties I had to pay big bucks for it. Now, however, a good set can be had for under $100.

Don't be penny wise and pound foolish, buy a 134 set. You will make use of it for the rest of your life.

Good luck,

The r-134a sets have sealed hoses that hold gas even after they have been disconnected. Most r-12 sets did not.

For this reason, cross contamination of gases in not likely using an r-12 set on r-134a, though there may be residual ester oil kicking around.

r-134a systems are more sensitive to moisture, so the open hoses are not the best. Really need to pre-purge the air out of them, but the EPA frowns on this (more than a little).

Getting a dedicated set is the best choice. They can cost as little as $75. Good investment, given the cost of A/C repairs.