Description
The Trane CNT04959 Low-Pressure Control Switch closes contacts on pressure rise at 41 PSIG to enable compressor operation. Its bellows mechanism responds to suction line readings, signaling controllers when refrigerant charge supports safe startup. Like chillers and packaged units in HVAC systems, it prevents running under low-charge conditions that oil loss or slugging. Connected through tubing to evaporator outlets in control panels, the switch cycles units during pull-down phases. Deep vacuum protection blocks liquid flood back. During low-pressure events, prevent compressor operation until refrigerant pressure recovers to the rated setpoint without manual reset.
