What condition causes the differential contacts on an oil failure control to open?

The differential contacts on an oil failure control are designed to monitor the oil pressure in a refrigeration or air conditioning system. When there is an increase in net oil pressure, it indicates that the oil system is functioning correctly and that the oil is adequately circulating to lubricate the compressor and other components.

In a properly operating system, sufficient oil pressure is crucial for maintaining the health and efficiency of the system. If the oil pressure rises beyond a specified threshold, it can trigger the differential contacts to open. This action is a safety feature aimed at preventing potential damage to the compressor or other components due to excessive pressure.

Understanding the importance of proper oil pressure management helps ensure the longevity and reliability of refrigeration systems, making it essential to monitor these conditions closely.