Liquid return during the running cycle. More commonly known as refrigerant flood back. The expansion valve plays a part in all the conditions here whether directly or indirectly this is obviously because the refrigerant can only really come this route.
What about the very special oil separating system of a VRV? Is it not too complex compared to common oil separators? What's the advantage of this system?
The original VRV 2 did not have a suction accumulator installed, this caused liquid to wash oil away and eventual seizure of compressor. The compressor would then draw locked rotor amps and blow the inverter board. All models after the RXY**MY1 had suction accumulator installed as far as I know.
Similar situation on a recent job, four Fujitsu units with tandem compressors, 6 comoressors died. Originally No overload installed in power circuit of compressor, bi-flow drier filter is located in a tight corner with sensor cables around, leaving a hard time to the service people who have to struggle on how to torch it off without burning his eyebrow and cables.
We have a similiar problem. Our site has 19 Daikin VRV condensers and 99 ceiling mounted cassette type evaporators. Within the last 3 years, over 15 compressors have failed as well as the circuit boards. the installation contractor had indicated that the failures are due to voltage problems. However the failures are limited to only five systems. The other systems are not affected. We did our own investigation into the voltage problems, however our data loggers did not reveal any problems. Can anyone assist?