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faryuki
28-05-2007, 04:06 AM
Dear Sir,

I have a system with two R/C in paralel, use ammonia refrigerant, now I have a problem with the oil, one compressor oil is black sometime there`s sludge and the other compressor some times oil become white and i suspect water is contaminant. Is there any causes for this case?

Many thanks for advise and help.

kind regards
Faryuki

taz24
28-05-2007, 11:18 AM
Dear Sir,

I have a system with two R/C in paralel, use ammonia refrigerant, now I have a problem with the oil, one compressor oil is black sometime there`s sludge and the other compressor some times oil become white and i suspect water is contaminant. Is there any causes for this case?

Many thanks for advise and help.

kind regards
Faryuki

Do they share the same oil management system or are they independant?
What is the temp of the system?

taz.

NH3LVR
28-05-2007, 01:40 PM
I have a system with two R/C in paralel, use ammonia refrigerant, now I have a problem with the oil, one compressor oil is black sometime there`s sludge and the other compressor some times oil become white and i suspect water is contaminant. Is there any causes for this case?
Faryuki

Hi Faryuki;
In the case of the black oil I would check the discharge temperature first, to see if you have carbon building in the compressor. Compare it to the other one.
In the few cases I have seen with NH3 with water in the crankcase there has been a leak in a oil cooler allowing water into the oil.
If the facility you are in has a quality control lab with a centrifuge it is a simple matter to fill a test tube with the oil and run it for a few minutes. This will separate the oil from the contaminates and allow you to see what is in the oil. Unfortunately we do not often have this available to us.
In lieu of this you can fill a clear container with oil and allow the mixture to settle. It takes a close look at the container afterward as the amount of water required to turn the oil milky is quite small.
We had this problem some time ago when the oil cooler failed on a Vilter. We hooked a hand pump to the oil system and pumped oil through to flush the lubrication passages. We were able to eliminate visible traces of water with one oil change.
Carbon could be coming from the crankshaft seal, although this usually moves outward, rather than into the crankcase.
What type of compressors do you have and what kind of system?

aawood1
29-05-2007, 12:58 PM
Hi Faryuki,
I have had Black oil and sludge build up in a Grasso RC 11 on Ammonia. What we found was high Temp. on 2 of the 3 high side heads as the discharge valves where not seating right and letting by. This higt Temp. was at the point where the oil would start to brake down and turn to carbon from the heat and working pressure. Also the oil separator return float valve was not working right. Only opened when the oil separator was about 1/2 full and the oil had been heated up from the discharge Gas.
So I would go with NH3LVR and TAZ24 and check the discharge Temp.
(Yes I know that we should have done more discharge valve service's/ Compressor's service's, but the man who pay's the bill did not want to at the time so he could save money.)
Arthur

faryuki
30-05-2007, 02:08 AM
Hi Faryuki;
In the case of the black oil I would check the discharge temperature first, to see if you have carbon building in the compressor. Compare it to the other one.
In the few cases I have seen with NH3 with water in the crankcase there has been a leak in a oil cooler allowing water into the oil.
If the facility you are in has a quality control lab with a centrifuge it is a simple matter to fill a test tube with the oil and run it for a few minutes. This will separate the oil from the contaminates and allow you to see what is in the oil. Unfortunately we do not often have this available to us.
In lieu of this you can fill a clear container with oil and allow the mixture to settle. It takes a close look at the container afterward as the amount of water required to turn the oil milky is quite small.
We had this problem some time ago when the oil cooler failed on a Vilter. We hooked a hand pump to the oil system and pumped oil through to flush the lubrication passages. We were able to eliminate visible traces of water with one oil change.
Carbon could be coming from the crankshaft seal, although this usually moves outward, rather than into the crankcase.
What type of compressors do you have and what kind of system?

Dear all , many thanks for the input...!
Compressor use MYCOM N8B, system is chiller to cool down the glycol as secondary refrigerant.

Regards

faryuki
30-05-2007, 09:43 AM
Do they share the same oil management system or are they independant?
What is the temp of the system?

taz.

They not share the oil to the other compressor.

The temperarture for glycol is -2 degC

Thank you

faryuki
30-05-2007, 11:29 AM
Dear NH3LVR,

I already check for the oil cooler of compressor with pressure test and its OK. Also I put it to the other compressor and compressor its OK, oil not become milky.
Now I suspect its glycol is leaking and suck in to compressor, is it possible? because we have big surge drum as accumulator too.

Please kindly advise.

many thanks

NH3LVR
30-05-2007, 12:57 PM
Now I suspect its glycol is leaking and suck in to compressor, is it possible?
Faryuki;
It is possible for Glycol to leak into the Compressor if the pressure is higher than the suction at any time.
If indeed your Glycol is leaking into the compressor, this is a VERY serious matter.
Glycol will reduce the lubricating ability of the oil, and cause failure of the compressor.
Get the oil tested as soon as possible.