Hello, Im new to this forum. I have a brand new small R22 Fuji rotary (on/off) compressor which I intend to use for 407C and therefore an oil change to Ester type is neccesary. Can only drain oil (~300ml) out of a hole I drilled close to the connection (HP) non from the suction line (muffler is removed). From what I have read there should be some oil also in the lower (suction) part or...?
/Lars S
Take it to Jiffy Lube.
Tell them you want 'The Works'.
Years ago, I drained the oil out of a window AC rotary, by tipping it upside down. Then power it up, and the oil blows out the high side.
You may be able to pump the new oil in, through the high side line.
Drilling a hole in the compressor shell? I hope you have the ability to weld it shut?
Thanks Christopher! Yes welding is no problem, I know many refr engineers but no one knows how to change oil...
If I only fill oil in the high side, will the suction side run dry until oil has been recirculated?
/Lars S
Someday I should cut open one of those rotary compressors. As I understand it, the high pressure side goes to the area around the pump. If it were an automotive engine, what would be called the crankcase. So, pumping oil in the high side should be same as filling the crankcase. The oil should lubricate nearly immediately. You won't get 100% of the old oil out, so there should be enough to lube for the first couple seconds.
That's just my experience from trying it with one compressor.
Why not get a compressor with the correct oil in it in the first place??
Thats logical, but the reason is that got this new compressor for free some time ago and it fits wery well (except for the oil) in my project which will be much cheaper to realize if I dont have to buy a new one.
Everyone with ideas around oil change in rotarys are welcome!
/Lars S
Wasn't sure what you meant by rotary so I looked it up. According to my research it's a screw pump. If that's the case then I have changed oil in a rotary compressors before.
Create pressure in the system then valve off any means for the pressure to bleed off once you shut it down. Find the appropriate outlet for the used oil and let the trapped are force it out. Alternatively provide an outside source of air pressure and do the same.
Thanks, yes, the big rotarys are of screw type but this is a small hermetic rotary compressor (as used in many residential split AC's), no service valves etc for oil; the oil is never ment to be changed. (Picture
All ideas are welcome!
/Lars S
Wrong.
Who's wrong. Certainly not me. "A rotary compressor" is a type of screw pump.
They are not veins. They are screws that are machined in a way that compresses the gas or liquid in a given direction.
Sorry. You are wrong. Vein pumps are Vane pumps. Vane pumps can be considered a rotary compressor, but when talking about air conditioner compressors the term" rotary compressor" is most likely a rotary screw compressor.
Hydraulic pumps can be any type of positive displacement pump. Usually a high pressure pump such as a piston, vane, gear or even a screw pump.
BTW pumps are not compressors. And Paul is right. Sorry.
Lars, Its not practical on a tin can but since you asked. Cut the compressor out of the system, turn it upside down and drain it. measure what you take out and put the same amount back in. You may be able to suck it out of the discharge line and pump it back in. That depends on your know how. Its going to take at least three oil changes to get the mineral oil down to an acceptable level. You need a rather expensive refractometer to measure the oil percentages between the POE oil and the mineral oil. You only have 15 mins to get the new oil in and the system sealed up. Otherwise youve wasted more of your time.
No, 'rotary compressor' refers to a very specific design, and is not a generic term for 'compressors that spin round and round in some way or fashion'.
A screw compressor is a screw compressor, not a 'rotary'.
Please be kind enough to tell us what you're doing. You building a walk in cooler, or what?
I know of three sub categories of rotary.
For smaller AC, I think rotary vane is common.
No, this is a heat pump project, the evaporator is approx 50m copper tube in the soil, the condenser is indoors blowing hot air. These systems are quite common up in our arctic regions. For me it is a low cost project were I can find most of the parts for free since I work in conjuction with a refrigeration company.
/Lars S
Hmm. So, you'd need a low temp referigerant, to absorb heat at low temps. R-22 could work.
Yes R22 should work and also it should work with the mineral based oil in the compressor...but R22 is forbidden and not available in my country since about 10 years :=3D( The gas to use in these applications nowdays is (normally) R407C, wery similar to R22 in pressure etc but ester oil is needed.
/Lars S
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