compressor loses oil

[boy]

Good Day Sir,

We encountering problem on Linde Multiset Compressor.We have 3 compressor on multiset low temp compressor.this is running for the past 4 months .compressor #2 always loses its compressor oil while the other two compressor operate normally and doesnt lose oil.the suction receiver has oil two sight glass.level of oil is on middle of the top sight glass.Once compressor 2 loses its oil, oil failure switch shutdown the compressor. we do not have any manual on this multiset.

please help.

[coolhibby1875]

hi boy

we look after similar set up,s in lidle stores in the uk also 3 compressor linde compressor sets and we find this happens all the time and almost all the time its due to liquid floodback caused by either iced up cases or multiple evaporator fan motors being seized.

[Mark]

Hi
I would start with inspecting the compressor which is tripping on oil.
Sounds like it is pumping its oil out quicker than it is being fed.

With Kind Regards
Mark

[Slatts]

As it's the same compressor that looses it's oil each time, I'm with Mark.
Is there a sight glass in the oil return line?
It would be worth your while to fit one on the branch that feeds the problem comp and see if you actually have oil returning to it.
I assume the oil level is controlled by either a lowside float or an electronic float / solenoid valve system?
Do the compressors have individual oil return strainers or is there a common one?
If all the oil return gear is good, I'd suggest, as I think Mark did, that the compressor is on the way out.

[RUSTY]

Hi, does the comp run unloaded, or maybe its the configeration of the oil return line/lines?

[boy]

We do a compression test on the compresor and we have discharge press test of 450 psi and it went down to 425 psi after 1 hour.Based on the test above what do you think sir.oil return line did not have a sight glass and doesnt have any oil regulator on the 3 compresor.

Any other suggestion is very much appreciated.

regards,

[boy]

Mark,
I:ve heard there are oil screws on each compresor say you have 3 so with the oil adjusting screws.Does it necessary to adjust it?
Any thougths?

regards,

[Slatts]

We do a compression test on the compresor and we have discharge press test of 450 psi and it went down to 425 psi after 1 hour.Based on the test above what do you think sir.oil return line did not have a sight glass and doesnt have any oil regulator on the 3 compresor.

Any other suggestion is very much appreciated.

regards,
Do I understand you correctly? you put 450PSI on top of the discharge reeds?

[750 Valve]

Do I understand you correctly? you put 450PSI on top of the discharge reeds?


think so... slammed them buggers shut.... they may never open again :D


they held though :D

[Slatts]

think so... slammed them buggers shut.... they may never open again :D


they held though :D
I should bloody well think they would!
They've probably got convex dimples in them that line up quite nicely with the ports now:D

[boy]

gentelmen

yes.450 psi then shut the comp.will not start the comp under that pressure.we only done the comp test.i was just asking guys why comp loses oil .

[Slatts]

Boy, all that test will do is stress your discharge reeds. it won't tell you anything about the condition of your piston rings or cylinders. if the bore and or rings are worn the compressor will pump more oil out with the refrigerant.
Before condemning the compressor though, I'd have a close look at the oil return system and find out if it is indeed returning the oil to the sump of the compressor in question.
I don't suppose the compressor has a lot of ice on it when it's running does it?

[R DAVIES]

Might be a bit late but this might help.

Sounds like this Linde Pack relies on suction accumilated oil to satify the compressor requirements.

If the other comps are working fine then there could possibly be oil starvation to that compressor. If this Pack has oil supplied via the suction accumilator the it can be adjusted/set correctly be adjusting the regulator on the suction accumilator.

This can be found under the associated compressor suction from the accumilator. It could be blocked or not set, if you have no info then i would recomend removing the nut and screwing the adjuster in fully, accuratley counting the number of turns and then returning it to the original possition, this might clear any blockage. Or you can check it agains the number of turns on a comp operating correctly.

If they are all different I would recomend you obtain a commisioning sheet from Linde and compare the comp data to the applied requirements and this will tell you how many turns to set the oil reg to.

Sorry to drag on!

[Magoo]

Strip down and re-build time. magoo

[chillled]

These linde packs used to have no separator or oil floats and rely on the suction lines to the comps being so far into the suction header which had an oil level in it, you could see this by a floating sight glass on flexi lines on the side of this. as i remember there was a valve that needs cleaning now and again. Also you experienced lads taking the mick out of the lad winding his poor machine up to 450psi, is anyone going to tell him how to do a proper pump test?? or shall I??

[Slatts]

you and R DAVIES have already broadened my knowledge base chilled.

re:
If this Pack has oil supplied via the suction accumilator the it can be adjusted/set correctly be adjusting the regulator on the suction accumilator.

And now I feel bad about my earlier flippancy.

[reymund]

hi' maybe you have broken gasket on your compressor

[Shibhrac]

To solve this problem, we should aask ourselves why when how the said compressor loses it's oil charge and why the oil pressure switch had tripped? We lose oil only during leaks put we call this oil migrant. Compressor pumps oil when liquid gets into the suction port. Liquid inters the compressor when there is poor heat transfer in the evaporator,crankcase heater is not working before the start up, or over charge in the cases of faulty evaporator fan motor. We have to put every thing back to normal and add the required oil, record the added amount ,and be ready to drain it . if the compressor has crankcase heater allow time to warm up the compressor.start the system and when the oil level become above normal drain it gradually.

[Slatts]

i would suggest you re-read posts number 13 and 15 Shibhrac

[geraray]

what is the maximum pressure I can apply on pack system to check and make sure of the maximum pressure a system can with stand?

[Joy]

Mark,
I:ve heard there are oil screws on each compresor say you have 3 so with the oil adjusting screws.Does it necessary to adjust it?
Any thougths?

regards,
Hallo Boy,
There are 1X oil return screws on each compresor(Suction Chember).Only 1/2 Turn the oil return screw.Run the compressor 1 Hr then check the oil level.

[andywill]

If you need any info on these type of linde packs I will be glad to send you the full PDF documents. It has all the settings for the oil levels, adjusting screws,compressor types and controllers plus commissioning etc. Just send me a message with your e-mail..

[Frank Day]

Hi andywill,

Plse mail me the PDF docs to fdref@hit.co.za

Thanks

Frank Day