Carlyle multiple reciprocating compressor systems/ low oil alarm in Carrier chiller

Hello Dear Friends,
I have a refurbish carrier chiller type 30HT.
After I started up the chiller both systems A and B sounds an alarm 50 and 51 " Low oil pressure compressor A1 lead comp. in sys. A and B1 lead comp. in sys. B. (Note the compressors have oil equalizer pipe in each system).
I added a required oil to both systems and then less an hour all the oil in sys. A "four comp." and sys. B "three comp." disappeared completely.
Now I am confused !!
What happened and what should I do?
Even if one compressor in work also drag the oil from the rests.
Is it compressor's o-ring or vales problem?
I'm waiting your kind help my friends.
http://www.hosbv.com/data/specifications/3258%20-%20Carrier%2030%20HW%20052.pdf

Did you have crankcase oil heaters operating for at least 24 hours before starting compressor?

Hi Magoo,
Thanks to you.
Of course we have crankcase heaters, but not operating always because we have shortage in electricity and have programmed cutting about 6 hours a day. And our ambient temperature is 39 centigrade.
Now why the oil not coming back to comp. case? 3GS oil is light or easy-moving.
I thought also that in working time the oil pump pressure is not higher than suction pressure at least 12- 35 psi. but why have this situation in both systems?

Quote:

---

Originally Posted by Magoo

Did you have crankcase oil heaters operating for at least 24 hours before starting compressor?

---