HelpCoolIt
14-01-2010, 11:13 AM
I must emphasise that I am an experienced Domestic Aircon serviceman that has been thrown in the deep end over the last two years. I now belive I can call myself a real fridgie. but I am still on a steep learning curve.
I have just replaced a Terry VS (V4) compressor on an old 400 gallon milk Vat with a reconditioned one. The old one seized and locked solid, gas charge gone, Oil everywhere shaft seal assumed to have failed. After re-commissioning with a new dryer in circuit I monitored the operation and found the oil levels dropping.
Upon further investigation I found the filter in the rebuildable Temprite 923 oil separator (never seen one before) to be torn and replaced it (this was then assumed to be the cause of the original failure), cleaned out the oil separator canister and used new oil.
Monitored operation removing excess oil as required.
Luckily I have a very smart farmer who also watched the system after I left.......Two days later I received a call, the oil level is very low. I returned, disassembled oil seperator to check new filter, rechecked float, rechecked needle and seat then over filled the oil seperator and pressurised it forcing oil back into the compressor confirming the oil seperator is working, monitored, then left.......Next call, Oil levels to high suggested run the vat and the oil rectified itself.
Today called oil low again. Added oil to compressor to prevent seizing, no apparent damage done so far. confirmed warm oil return on separator. Separator appears to be still working.
I did a pump down test, compressor pulled down to negative pressures in a reasonable time and then with the suction service valve front seated it held them.
This is a 30+ year old system. If the oil seperator seams OK and the compressor seams OK what else could be causing the erratic oil levels.
A friend suggested that Terry VS compressors were cast with the sight glass too high and will normally show low oil levels but I have another exact same system with a worn shaft seal that I have overfilled with oil to keep in operation till another reco compressor arrives (tomorrow) that system barely fluctuates
My boss has suggested that if the rings weren't done in the reco then the oil could be atomising as it blast past the pistons into the refrigerant and be carrying past the seperator. But from my test I believe the rings to be OK
With the testing that i have done I don't understand how anything could be causing an oil level problem, this system hasn't had a problem for 30+ years.
Does anyone have any ideas as to were I might look next.
Thanks
Dean
I have just replaced a Terry VS (V4) compressor on an old 400 gallon milk Vat with a reconditioned one. The old one seized and locked solid, gas charge gone, Oil everywhere shaft seal assumed to have failed. After re-commissioning with a new dryer in circuit I monitored the operation and found the oil levels dropping.
Upon further investigation I found the filter in the rebuildable Temprite 923 oil separator (never seen one before) to be torn and replaced it (this was then assumed to be the cause of the original failure), cleaned out the oil separator canister and used new oil.
Monitored operation removing excess oil as required.
Luckily I have a very smart farmer who also watched the system after I left.......Two days later I received a call, the oil level is very low. I returned, disassembled oil seperator to check new filter, rechecked float, rechecked needle and seat then over filled the oil seperator and pressurised it forcing oil back into the compressor confirming the oil seperator is working, monitored, then left.......Next call, Oil levels to high suggested run the vat and the oil rectified itself.
Today called oil low again. Added oil to compressor to prevent seizing, no apparent damage done so far. confirmed warm oil return on separator. Separator appears to be still working.
I did a pump down test, compressor pulled down to negative pressures in a reasonable time and then with the suction service valve front seated it held them.
This is a 30+ year old system. If the oil seperator seams OK and the compressor seams OK what else could be causing the erratic oil levels.
A friend suggested that Terry VS compressors were cast with the sight glass too high and will normally show low oil levels but I have another exact same system with a worn shaft seal that I have overfilled with oil to keep in operation till another reco compressor arrives (tomorrow) that system barely fluctuates
My boss has suggested that if the rings weren't done in the reco then the oil could be atomising as it blast past the pistons into the refrigerant and be carrying past the seperator. But from my test I believe the rings to be OK
With the testing that i have done I don't understand how anything could be causing an oil level problem, this system hasn't had a problem for 30+ years.
Does anyone have any ideas as to were I might look next.
Thanks
Dean