Chiller AHU Pressure Cut off Switch controls for the HVAC units

Mostly HVAC manufacturers provide optional protective controls for the HVAC units they produce. In the past, these controls were standard features installed on every unit, but market pressures toward cost reductions resulted in their removal as standard features/benefits in lieu of currently offering protective control as options.

The compressor in a refrigeration or air conditioning plant has to be provided with some safeties to protect it from operational faults. The three common safeties provided are the high-pressure trip, the low-pressure trip, and the low oil pressure trip among the others. A compressor has to be protected against high pressure that can cause structural failure therefore a high pressure cut out is provided, similarly any deficiency in the oil pressure can damage the bearings and a low oil pressure cut out has to be provided, a lower atmospheric in the pipeline can cause air ingress and therefore must be avoided. In this article, we discuss the different safeties one by one.