Thread: Oil for LPG Air Con.

BTW Dougal, can't recall if anyone answered your Q on compressor oil.
Most all old mineral oil type compressors used Suniso 5GS or equivalent, an oil with a viscosity of 525SUS @ 38*C.
I'm buggered if I know why they still quote the viscosity in an outdated/obsolete scale, but without checking I'm guessing it would be somewhere between an ISO 68 and 100 oil.

Originally Posted by rick130

BTW Dougal, can't recall if anyone answered your Q on compressor oil.
Most all old mineral oil type compressors used Suniso 5GS or equivalent, an oil with a viscosity of 525SUS @ 38*C.
I'm buggered if I know why they still quote the viscosity in an outdated/obsolete scale, but without checking I'm guessing it would be somewhere between an ISO 68 and 100 oil.

The oil I used was quite a lot thinner than that. But the PO did something dodgy with the compressor, it's noisey and it's days are numbered anyway.

Ladas is helping me source some real stuff.

Originally Posted by rick130

BTW Dougal, can't recall if anyone answered your Q on compressor oil.
Most all old mineral oil type compressors used Suniso 5GS or equivalent, an oil with a viscosity of 525SUS @ 38*C.
I'm buggered if I know why they still quote the viscosity in an outdated/obsolete scale, but without checking I'm guessing it would be somewhere between an ISO 68 and 100 oil.

Rick

5 GS = 68 CsT (or ISO 68)

So something like Hyspin AWS 68 would be appropriate?

Originally Posted by procrastination inc

So something like Hyspin AWS 68 would be appropriate?

No they have to be suitable lubricants for refrigeration

Mineral Oils Suniso or Shell Clavus

There is a plethora of POE manufacturers

Then there are PAO's - there are a few around.

...........but if you are using R12 or HC's mineral oil is okay, PAO is better.

Hyspin AWS 68 is hydraulic oil

so a synthetic 68 then?

Originally Posted by procrastination inc

so a synthetic 68 then?

Either a PolyAlphaOlafin (PAO) or a Mineral (MO)

The PAO is fully synthetic (or synthesized)

two major factors with refrigeration oils is

1. <30 PPM of moisture for mineral oils (<50PPM for POE's/polyol-esters)
This is critical, as moisture reacts with the refrigerant to form acid, and in the case of POE oils, they become acidic. Non refrigeration grade oils have too high moisture content.
One advantage with PAO's is that they are far less hygroscopic than mineral, POE, PAG's or AB's. If a tin of refrigeration oil is left open to the atmosphere, it absorbs moisture from the atmosphere, and in the case of POE's and PAG's, this is almost an instant occurrence. After a while, you can see the change in colour of the oil when this occurs.

2. low wax content for mineral oils which must incorporate a low floc point (temperature at which wax precipitates out)
Obviously this isn't relevant and doesn't happen with the synthetics.