First of all I want to apologise if my English is not the best. Just wanted to share with you a common VRF problem when brazing without nitrogen. Indoor Unit #0 with stuck wide open EEV because of the oxidation made while brazing without nitrogen. All of the liquid/gas refrigerant just goes trough the evaporator coil with no working evaporator fan in order to transfer that heat. Goes back to the suction, filling up the accumulator which may end up flooding the compressor. From the outdoor unit side: The unit’s logic will decrease compressor’s frequency / turn a compressor off (decreasing refrigerant mass flow), as you may see it just happened to compressor #1, due to the suction low super heat. From the Indoor unit’s side: You can see that the some of the indoor units which demands cooling capacity (#7 , #10) are “starving” and making a relatively big steps opening of the EEV around 850 steps (out of 2000 steps). Suction super heat in this screen can be calculated by this formula: SH = Suction1Temp- Saturated T_Ps Few knocks and it came back to work just fine. Edit: I think it is worth mentioning the how I determined for indoor unit 0 a stuck open EEV. On the screen you may only see the steps output goes to the EEV. At this moment it is closed therefore your temperatures at evap in and out should be around the room temp with no big differences between them. In here you can see refrigerant enters at 5°c (41°f) and leaving at 4°c (39.2°f). #teachme #vrf #samsungvrf #troubleshooting

Posted by Deleted (7b938969) at 2021-03-30 21:32:31 UTC