start refrigerating machine

[QQQ]

Situation:
I have two refrigerating circuits (R-22) in common evaporator.
Temperature of boiling -28C (-18.4F). The leading compressor at first
is ON. OK.
Through 15-20 min. the catching up compressor is ON.
After that the icing on the filter,suction line is formed,
There are attributes of a damp course.
Through 20-25 min. the refrigerating machine is stabilized.
Question to the connoisseurs - It is normal whether or not?
(I hope you me have understood)

[Andy]

Hi, QQQ
you english is much better than my Russian, but still lacking something
-28 deg C evaporation, maybe -20 deg C at the compressor, you will have quite a bit of ice on the compressor, this doesnot mean wet compression. Measure the temp and pressure at the compressor inlet, same temp for pressure or within 2 deg C and you have wet compression.
Regards. Andy

[Prof Sporlan]

As Andy notes, superheat readings would confirm if you are having floodback programs, but your system may well be operating normally.

[QQQ]

Thank all for the answers!
More correctly to tell, that two independent circuits(two vertical
screw compressors) have two evaporators everyone, and work on common water cooler. Is absolutely correctly noticed that on an output evaporator T=-18C. Further refrigerant flows through
liquid suction heat exchanger and temperature rises up to 2-10C on an input of the compressor.