Compressor loosing oil

[aupanner]

I wonder if any body has any ideas on my problem. I have just started working on a Geneglace ice machine and the oil level keeps droping in the compressor sump till machine trips off on oil pressure fault. The compreesor is a Copeland D6DH 3500 the refrigerant is R22. I have fitted a new oil seperator and changed the 1/4 return line to 3/8, The sight glass is clear on the liquid line. I have messed around with the expansion valve but this makes no differance. I changed the liquid line core drier and am running out of ideas. could there be damage in the compressor throwing the oil around the system? Could the oil be lying in the ice machine drum or suction accumulator if so why is it not returning? The machine will run for a couple of hours before tripping off.

[chemi-cool]

In the suction accumulater there is a small hole in the pipe where the oil is sucked in on its way to compressor sump. It can be blocked from something.

was there any changes in the evaporator temp?
A faulty TXV will slow refrigerant and oil flow back.

Oil filter in the sump should be clean.

Take your time, its there and you will solve it.

[powell]

aupanner,

You've stated that it "keeps" tripping but you didn't say what was done after that.

Does the crank fill back up, are you adding oil, what are you doing after the LOC lockout?

[Magoo]

There is an inline heat exchanger on the oil recovery line back at the ice head, generally covered in insulation. Check it is not leaking internally.
magoo

[aupanner]

When it trips off and left for a couple of hours it does fill back up on start up

[old gas bottle]

think as a starting point i would restart it and when the glass is full then drop the oil,i,am thinking its mineral unless you say otherwise, charge with with a semi synthetic oil and see how it goes,after all low temp and R22 with mineral oil often caused problems.;)

[powell]

Is this definition similar to what you're seeing?


While the compressor is running the oil disappears from the sight glass and the LOC cuts out. The oil then returns while the compressor is off. The LOC reset button is pushed and it starts again.


If so, you may have a pressurized crank which causes "blow by". This results from the compressor running hot, breaking down the oil and wearing out the internal components. The worn cylinder walls then bypass gas which pressurizes the crank due to the internal check valve between the crank and motor compartment closing. After it sits idle the check valve opens and the oil returns.

There is another valve in the crank called the Crankcase Ventilation Valve. When the crank is pressurized this valve opens to the suction chamber to relieve the pressure.

In a "blow by" situation the excess pressure built up in the crankcase may exceed the ability of the crankcase ventilating valve to vent the crankcase causing the check valve to close.

The oil pump is still picking up oil in the crank and pumping it through a drilled crank where it exits into the motor compartment.


Measure the crank pressure and the suction pressure and if there is a pressure difference of 2 lbs or more then this is your problem.


Replacing the compressor is the only solution if you have a worn compressor. Then you must find the reason for the overheating or it will happen again.

Here is a picture that might help.

[mbc]

It is better we go step by step1-Check your oil quality2-Did you vacuumed your system (air effect discharge temperature and oil goes to system)3- Are your system (compressor) has fan cooling system on top of cylinders or not.4-Are your pipe direction on slope is correct5-Did you put U in your system 6-In Suction accumulator and in all system we have oil is circulating so in first start we lose some oil ( Goes to system) So, we should add it .7-You wrote after tripe and off your system when you start oil come back to compressor, why? because your evaporator temperature goes up and your oil in system can move faster , So this sound say us you have to check your oil again and make it sure for right 0one I think it better you change it and use 3 GS grade

[aupanner]

Thank you all for your replies so far. I will be heading back to the factory on Monday morning.

[aupanner]

The compressor is ok.The crankcase pressure is the same as the suction pressure if any thing it is 1 psi lower. There is nothing coming back the oil return line frome the ice machine drum, this is where my problem lies.

[mad fridgie]

Are you rectifing (heating) your oil return out of the drum?

[aupanner]

went tback this morning and pumped down system and cut oil return pipe and blew nitrogen back to wards drum.reasembled and vacumed system. ran on test and the pipe was freezing back to 2/3 of heat exchanger (great). After an hour and a half sitting like this the frost melts off indicating that the flow has stopped. It must be a fixed oriface as there is no hand valve on the line and also I have no drain tap at the bottom of the drum either. If I pump down system and heat up where I think the oriface is I can get the flow going again but it stops after a while . Some thing in the systen is blocking the oil return line. The refrigerant is R22 and oil is 3gs mineral. I am thinking of fitting a drain valve to bottom of pipe at bottom of drum,changing core drier and oil. Any thing else I should do?

[flavenido]

The compressor is ok.The crankcase pressure is the same as the suction pressure if any thing it is 1 psi lower. There is nothing coming back the oil return line frome the ice machine drum, this is where my problem lies.
Your problem is indicative of wear off oil pump. Oil pressure must be higher than suction pressure say 10 to 20 psi to have good lubrication and prevent heating of your compressor. When your compressor becomes abnormally hot, more oil will flow out from the compressor and stay in the evaporator. Check oil pump casing/gears for any loose contact.

[aupanner]

I am getting 45 psi oil pressure above suction pressure

[RANGER1]

Just a few thoughts .
Maybe it is undercharched for oil return to work consistantly .
I'm assuming an oil skimmer is used off level in drum .

Oil return float on oil seperator can also blowout or heat up oil in sump of compressor if it is leaking or jammed open .

[powell]

The compressor is ok.The crankcase pressure is the same as the suction pressure if any thing it is 1 psi lower. There is nothing coming back the oil return line frome the ice machine drum, this is where my problem lies.

Sounds like your on the right path. Sometimes it's a matter of "the process of elimination" ;)

Let us know what you find!

[D.D.KORANNE]

Geneeglac icemaker ( flake ice ) runs into such a difficulty sometimes . Since it is flooded oil has a tendency to get logged up there. Many a times a ballast system offered by sporlan

[aupanner]

Finally solved problem, a bit embarassing really. Firstly I just started looking after this machine and today I drilled a hole in the bottom pipe to the drum and removed 20 litres of oil. I then brazed in a fitting and cap. The problem with the compressor loosing oil was the expansion valve was shut down too much and the refrigerant level in the ice drum was too low to allow the oil to return to the compressor. Thank you all for your help and what a good forum this is.