What might cause a unit to short cycle on low pressure control?

A unit may short cycle on low pressure control primarily due to refrigerant loss. When the system experiences a loss of refrigerant, the charge becomes insufficient for proper heat exchange, leading to a drop in pressure in the evaporator. The low pressure control is designed to protect the system by shutting it off when the pressure falls below a certain threshold, which prevents damage. This frequent cycling on and off due to low pressure results in inefficient operation and could lead to further problems if not addressed.

Other factors may contribute to cycling, but they operate under different principles. An excessive refrigerant charge can lead to high pressure issues rather than low, while improper thermostat calibration could cause the system to behave erratically without directly causing low pressure short cycling. Lastly, blockages in the evaporator would typically cause a reduction in cooling performance and might lead to high pressures rather than triggering the low pressure control. Therefore, the loss of refrigerant is the most direct cause of short cycling on low pressure control.