Each start draws locked-rotor current and stresses the compressor, and short runs never dehumidify properly because the coil does not stay cold long enough to drain. Causes include oversized equipment, a thermostat in the path of supply air, a pressure switch tripping on low charge or high head, iced coils and faulty controls. Most systems carry an anti-short-cycle delay of a few minutes to protect the compressor.
It's short cycling on the low pressure switch, three minutes on and off, check the charge before you blame the switch.
Also heard as
- short-cycling
- rapid cycling
Related terms
LRA
Locked rotor amps: the current a motor draws at the instant of starting, before it turns, listed on the nameplate.
Iced up
Describes an evaporator coil or suction line coated in ice because it is running below freezing.
Cooling load
How much heat and moisture a cooling system has to pull out of a space each hour to keep it at design conditions.
Contactor
A heavy-duty relay that uses a 24 volt control signal to switch line voltage to a compressor and condenser fan.