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efficiency/capacity loss using fan cycling control
I'm working with a 3.5 tonne split unit needing to run year round with outdoor ambient temps going down to 32F or lower. There is a fan cycling control installed to maintain head pressure as well as a crankcase heater. This is for a computer server room and according to my calculations the heat load is around 50% of total capacity based on room size and power consumption.
When outdoor ambient temps are around 70F and above, all is well. The room is able to reach and maintain 71F with apparent consistent compressor cycling patterns (there's a temperature recording device in the room).
However, when outdoor temps drop, even a few degrees, the system is no longer able to maintain the temp and it appears the compressor is now constantly running; or at least is no longer cycling with any regularity/apparent pattern.
When outside ambient returns to 70F and above, operation returns to normal.
Is this the expected operation when using a fan cycling control to maintain head pressure?