Oil Trouble on LT Pack

[ice_p]

Got an LT pack at a store and having problems with oil on one of the comps on it.

There are 5 comps on the pack each with liquid inject and oil is fed from a sep into the res then into seperate oil floats/regulators. The problem is that compressor 4 just seems to keep filling up with oil regardless of how the float is set. Have replaced the comp float which has had no effect. The sep float valve has been dropped and cleaned as this was sticking shut originally. Oil pump on comp is ok got about 40 psi diff. Checked diff valve on oil resevoir to suction 20 psi diff. Level on resevoir is just above bottom sight glass just over a third full.

Its a strange one as other 4 comps seem to control oil level fine. To get the level right and not risk the comp hydrolicing have basically had to leave oil in the system at a minimum anymore and it just fills this comp 4.

Any ideas would be most appreciated.

Ta!

[fowlie]

has the oil res got a pressure diff valve on it and is it maintaining the correct pressure in the res

[ice_p]

Yeh its maintaining a 20 psi diff above suction

[fowlie]

i take it the oil strainer in the comp is clean

[ice_p]

Certainly is yeh

[spacemanmark]

i have had it in the past were there is so much oil in the reservoir that the oil is blowing over through the diff valve and entering the suction header, this just happened to be over the suction line to compressor 4.

Worth a look.

Mark

[ice_p]

It looks like the extra oil is coming from the suction. As I'd said before the level on the resevoir wasn't too high but we have since pumped the pack down a number of times and emptied 4 full resevoirs worth of oil and still have enough left. It seems that someone has previously been ignoring the sticking float and been banging a load of oil in. All the excess oil must have worked its way around the system when the seperator float had previously stuck and filled up. I'm hoping things are going to be settling down with this pack now but I'm sure we may well have to drop more oil and clean the seperator float again in the not too distant future.

Thanks all for your input!

[ice_p]

Very strange how it only affected that comp. 2 though?

[ice_p]

Comp. 4 I mean