Frothy Oil.!!!

[N.Lewis]

Hi Guy's.

Just a quick one, doing basic maintenance check on an isovel under floor air con unit today, unit has two comps, everything o.k unit running fine, but noticed number two comp oil sight glass was full of frothing white oil, does this mean i could have an acid problem occuring??..Just want to get this sorted before it causes any major probs.

Thanks for any suggestions!!

[zarohliburd]

dude just change the compressor dont give ur self any added trouble

[zarohliburd]

if the compressor is sercicable clean it up and replace the oil

[taz24]

Hi Guy's.

Just a quick one, doing basic maintenance check on an isovel under floor air con unit today, unit has two comps, everything o.k unit running fine, but noticed number two comp oil sight glass was full of frothing white oil, does this mean i could have an acid problem occuring??..Just want to get this sorted before it causes any major probs.

Thanks for any suggestions!!

Just because the oil is frothy does not mean it has acid.

Frothy oil is caused by many reasons.
Acid would only be in there if moisture has got in in the past.
If the system is gas tight and no known problems then the likelyhood that it is acid is very slim.

If you are worried about it why don't you drop some oil and test it?

taz.

[taz24]

dude just change the compressor dont give ur self any added trouble

Why would changing what could be a perfectly good compressor for another one solve the problem?

I personaly think that that type of attitude is the worst possible for the industry.

Why would changeing the comp solve the problem?
If it is acid, well what about the other comp? The two comps on the same system will suffer with the same oil. Why would changing one comp cure it of an acid problem?

Changeing components without finding out why they failed is the worst type of repair I can imagine and the only reason sombody would that would be for a quick fix and a quick buck.

taz.

[N.Lewis]

Cheers chaps!!

Taz, will check oil, have testing kit, but not till monday off to work christmas do, and massive hang over.

[The Viking]

Foamy/Frothy oil...

The most common reason for this is liquid refrigerant entering the compressor.
I can not see any reason for the oil to foam due to acid, this isn't to say that it doesn't have acid in it but to find that out you need to test it.

Have you checked the super heat?

[taz24]

Cheers chaps!!

Taz, will check oil, have testing kit, but not till monday off to work christmas do, and massive hang over.

Have a good one.

taz.

[sohail]

Hi Guy's.

Just a quick one, doing basic maintenance check on an isovel under floor air con unit today, unit has two comps, everything o.k unit running fine, but noticed number two comp oil sight glass was full of frothing white oil, does this mean i could have an acid problem occuring??..Just want to get this sorted before it causes any major probs.

Thanks for any suggestions!!

hi, just check crank case heater if it is working or not sometimes foaming of oil occurs due to defective heater.

[PRESS]

oil foaming is primarily caused by rerigerant mixing with oil. i would say look out for the following points:-

1) ensure that you are boiling off excess liquid refrigerant returning to the compressor.
2)check weather your crankcase heaters are working too.

I would like to think that it is highly unlikely that you have an acidic oil problem

[RackMechanic]

You didn't provide enough info for an absoulte diagnosis, but the first thing that comes to my mind when I see foaming oil is floodback.

You mentioned two compressors, is the other running? If so, turn it off. Wait a half hour or so, this will increase the load on the evap of the foaming circuit, (I'm assuming both circuits are removing heat from the same area), then if the foaming stops, or is reduced, you know to look for problems like reduction of air flow, evap fouling, Unloader not unloading.

If the foaming does not at least decrease a little, but stays the same, I would check the metering device.

I have been a supermarket refrigeration mechanic for 31 years, and I would never suspect oil or a bad crankcase heater. I would suspect a dirty or poor heat transfer problem at the evaporator, a defective metering device, or a stuck unloader.

Tell me this, what is the unit being used for? Refrigeration, Air Conditioning Etc., Etc., Are the compressors piped in tandem or are they seperate circuit?

Total system superheat, measured at the suction line about 4 to 6 inches before the compressor, of less than 15 degrees, will let you know you have floodback.

[markacs]

Frothing Oil-check The Superheat And The Crackcase Heater.
If It Foams On Startup That Would Be Liquid Refrigerant Dilution From The Start Before Valve Throttles Or Too Low Superheat Or Liquid Migration Because Of The C/case Heater Not Functioning On "off" Cycle.
Bro,never Acid As It Would Have Eaten The Windings Before You Knew It.

[ismayil59@yahoo]

Foamy/Frothy oil...

The most common reason for this is liquid refrigerant entering the compressor.
I can not see any reason for the oil to foam due to acid, this isn't to say that it doesn't have acid in it but to find that out you need to test it.

Have you checked the super heat?

chek superheat liqid refrigirant is entering into your cmpressor

[borodave1973]

First I would check th crankcase heater as most other people have suggested wouldn't have thought it would be acid myself

[N.Lewis]

Hi guys.
Just want to say thanks for all prompt replies and suggestions...Just to let you know how am getting on, checked c/c heater working o.k, also super heat reading 21.7 degC so all good there, Exp valves all good, also oil sight glass this morning now showing just half oil no foam???..Will keep an eye on unit and also finger crossed!!!

[The Viking]

Hi guys.
Just want to say thanks for all prompt replies and suggestions...Just to let you know how am getting on, checked c/c heater working o.k, also super heat reading 21.7 degC so all good there, Exp valves all good, also oil sight glass this morning now showing just half oil no foam???..Will keep an eye on unit and also finger crossed!!!

With a superheat that high, something must be wrong.

Just to make sure, you agree that superheat is the difference between the saturated temperature on your suction gauge and "real" suction line temperature as measured with a thermometer?

[frank]

With a superheat that high, something must be wrong.

Just to make sure, you agree that superheat is the difference between the saturated temperature on your suction gauge and "real" suction line temperature as measured with a thermometer?

But don't forget that you should only measure Superheat at or near design conditions. High superheats will be measured during pull down.

[The Viking]

True Frank,

Should of course have read:

With a superheat that high, something must be wrong.

Just to make sure, you did measure it during stable running conditions and you do agree that superheat is the difference between the saturated temperature on your suction gauge and "real" suction line temperature as measured with a thermometer?