What pressures does an oil pressure differential switch utilize to open contacts to the time delay heater?

The oil pressure differential switch is a critical component in refrigeration systems, particularly in maintaining the proper oil flow and ensuring that the compressor operates efficiently. This switch monitors the pressure difference between the oil pump discharge pressure and the compressor crankcase pressure.

When the oil pressure in the crankcase drops below a certain threshold compared to the discharge pressure from the oil pump, the differential switch opens the contacts. This action activates the time delay heater, which warms the oil and helps return it to the necessary level for efficient compressor operation. This is vital because maintaining proper oil pressure is essential for lubrication and cooling of the compressor components, preventing potential system failures.

Using pressures from the system suction and discharge or from a sensing bulb alone fail to account for the specific relationship that the oil pressure differential switch monitors, which is focused directly on oil delivery and compressor health.