Johnson Controls P10FC-4 2-Stage SPDT Low Pressure Switch 3/20 PSI

The Johnson Controls P10FC-4 is a 2-stage, single-pole double-throw low-pressure switch for control of air pressure in HVAC systems. Constructed with metallic material, it has pressure control of 3-20 PSI and can work with up to 120VAC. The P10FC-4 uses a pressure-operated system that mechanically switches electrical contacts inside depending on the pressure detected. It can cause actions at two different pressure points, regards to the two stages. For instance, it can switch on a furnace fan at a low pressure level (for instance 3 PSI) to enhance air circulation and then a compressor at a higher pressure level 10 psi to cater for the increased heating needs.