CellarPro Fan Cycling Control Switch (P/N 6972). All CellarPro cooling units can be operated in temperatures down to 40F without additional equipment.

Below 40F, you must add the addition of our compressor heater item #1727, which is included as standard equipment for all outdoor hoods and cooling units, and allows CellarPro cooling units to be operated in temperatures down to 20F.

Below 20F, you should add the fan cycling control switch, which allows CellarPro self-contained and electronic control split cooling units to be operated in temperatures down to -20F.

The fan cycling switch is required to assist the thermal expansion valve (TEV), which regulates flow of refrigerant based on system pressures. When those pressures fall outside of the design range, eg below 20F, the TEV does not regulate properly because the pressure of the liquid feeding the TEV gets too low for efficient regulation of the refrigerant flow, thereby resulting in reduced cooling capacity of the cooling unit.

The fan cycling switch compensates for the low pressures by turning off the condenser fan when system pressure falls below 75PSIG, thereby causing the system pressure to rise until it hits 120 PSIG, which is when the fans will turn on again.

Please note: At temperatures below 20F, in addition to requireing the fan cycling switch, CellarPro split systems must always be configured with electronic control, not valve control.