Hello.

We have 2 chiller units with 3pc of TT500 turbocor in each unit and Danfoss MXC Control.

I have a problem with discharge checkvalves that i assume, that starts to clutter then we run 3of3 compressors.
It dosent matter if its Comp 1 Comp 2 or Comp 3 that stage in as the last compressor.

Sometimes is then it stage in and checkvalve clutter and the compressor fails on High superheat / 3-phase current trip or Bearing failure.
And other times the stage in is complete and after like 4-5min one of the checkvalves starts clutter and the turbin trips on the same.

Conditions of the unit is following:

500 ton (1750kW) on each unit

Condenser EWT 25 and LWT 35°C
Evaporator EWT 14 and LWT 6°C

What i see in the 3G tool then the valve start clutter is that the superheat rise from 0°K to 20°K in the compressor and the 3-phase amps goes up.

I have seen some thread with simular problem.

But dose anyone know what it is that make this problem with the checkvalve clutter?