Hi, all. One of our VRF systems has a problem. A week ago call us that one of systems is not heating. Ambient temp was 5-6 deg. cels. The system is 30HP with 6 compresors (1 inv. and 5 on/off). Hi pressure was near 18-19 bars, low pressure 2 bars, and going down. Both EXV ware 20 % open, and going closer to 10%. Compressors at the start run 3 of 6, but for 30 min. turn off 2 of them, and the Invertor one is slowing down.
Errors wich shows are:
Low pressure fall protection
Discharge gas Superheat falling retry
Pressure ratio control
High pressure fall protection

Temp on the top of the compressors is not more than 40 deg. cels. (normally its 80-100 deg)

Buth when the weather get better like 15-16 deg. cels., evrything looks fine.

So I think that is insufficiente refrigerant (R410A), but I'll glad to hear if there is any other viewpoint, becouse recovrering is not that easy part and the other reason is that we can't find any leak....for now.

Thank You futurful and I'm sorry for my English