Converting from R12 to R134a
DaviesParticipantApril 27, 2016 at 5:26 pmPost count: 103
Has anyone recently tried to convert their AC system? I am in the midst of switching over my 1990 780 and have found it difficult to source certain tubes that have to come off of the receiver dryer. Volvo has limited retrofit parts available.C GuillaumeParticipantAugust 30, 2016 at 4:04 amPost count: 51
You can find a conversion kit here:
My US 780 was converted to R134a by the previous owner.dn010ParticipantAugust 30, 2016 at 2:19 pmPost count: 50
I know you’re seeking the lines coming off the drier but for what it is worth – I am certain the drier can be cross referenced at your local parts house if you’re in the US. Here are some things to consider when converting to R134:
R134 molecules are smaller than R12, if your hoses are designed for R12 and are not upgraded, barrier hoses, the R134 will slowly leach through the rubber leaving you to top off the system on occasion. O-rings should also be replaced when converting.
Also you should at the very least replace the accumulator/drier and orifice tube. The system should be flushed to remove any contaminants and oil. Drain the compressor and refill it with Ester oil, as it is compatible with whatever trace mineral oil that may still be in the system.DaviesParticipantAugust 31, 2016 at 9:58 pmPost count: 103
I have completed the conversion. Flushed and cleaned the compressor, all new o-rings on the entire system (that took a while), new dryer and orifice tube. All is well but I now have a squealing noise coming from the orifice tube. I used a variable design, which was recommended and am planning on doing an evac, replacing the orifice tube and then doing the recharge. It runs great, super cold air, but sounds like a dying animal at times!dn010ParticipantSeptember 8, 2016 at 7:27 amPost count: 50
I know, stupid question – but did you make sure the variable orifice valve (VOV) was installed the correct direction? Was it missing the O-ring or loose when installed? I think VOVs are great but unfortunately they don’t always work for older applications. Some people get away with no issues, others rip them back out and put the orifice tube back in.
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