Trane CNT4959 Low Control 25 Open 41Close

The Trane CNT4959 Low Control is a pressure control switch used in HVAC systems. It works like a safety switch, recording system pressure and using preset settings to open or close electrical circuits. The switch opens at 25 PSI, shutting off the compressor's power, under typical circumstances. It prevents the compressor from running at low pressure, where it could be damaged. On the other hand, when the pressure reaches 41 PSI, the switch closes a second time to protect the system by stopping the compressor. It may be a sign of a fault in the system.