Oil Lifting Problem in NH3 screw compressor

[US Iceman]

We drain the 10 liter oil for every 24 hrs running from PHE chiller surge drum.

If you have to drain this much oil every 24 hours, then the compressors/oil separators are pushing too much oil into the system.

And, your problem may be caused by this...

Opoeration at -6 deg. evaporation, 30 deg condensing, 150 psi discharge

Since you provided the discharge pressure in psi, are the temperatures above in °C or °F?

[SURESH YADAV]

If you have to drain this much oil every 24 hours, then the compressors/oil separators are pushing too much oil into the system.

And, your problem may be caused by this...



Since you provided the discharge pressure in psi, are the temperatures above in °C or °F?

Discharge temparature is 100 °C

[US Iceman]

If the condensing temperature is 30°C (86°F) and you have 100°C (212°F) discharge temperatures the discharge superheat of the compressor is 70° (or 126° on the F Scale). That is very high!

At the same time you say the discharge pressure is 150 psi, which is fairly close to the saturation temperature of your condensing temperature.

You either have extremely high suction superheat or no oil cooling based on what this seems to be.

Another possible cause for high volumes of oil loss is if the discharge pressure suddenly decreases. Do you have hot gas defrost on the evaporators? When the coils go into defrost, what happens to the discharge pressure?

[Poodzy]

Another thing to look for is a bad check valve in another machine that may be off.. If you have another machine on the same system and it is off close the suction valve see if this solves your problem. (had similar issues here) Not sure how its piped in. But if you have a machine that is losing allot of oil i would start there. Are you draining the oil from the compressor or the surge drum? Is the sight glass on the oil separator side full? Is the pump in working order for oil return? Just some other ideas

[vinodvlimaye]

Discharge temparature is 100 °C

Have you installled secondary filter with what mesh size ?
& coalsecent filter with what size ?

[vinodvlimaye]

If you have to drain this much oil every 24 hours, then the compressors/oil separators are pushing too much oil into the system.

And, your problem may be caused by this...



Since you provided the discharge pressure in psi, are the temperatures above in °C or °F?

Have you used the Bitzer oil seperator , or you have made its own