Alco Controls PS2-W7A Dual Adjustable Pressure Control Switch

Alco Controls PS2-W7A Dual Adjustable Pressure Control Switch (4360100) is a compact refrigeration/air‑conditioning protection device that provides two isolated SPDT contacts for monitoring the low and high pressure sides with automatic reset capability. The auto‑reset version is designed to re‑energize after a fault condition, making it suitable for continuous compressor protection in typical cooling and HVAC circuits. The low‑pressure setpoint is adjustable from about -0.5 to 7 bar, while the high‑pressure setpoint covers roughly 6 to 31 bar, with a differential in the vicinity of 3.5 to 4.5 bar to minimize nuisance cycling. The unit uses a 115–230 V AC supply and features a 7/16″‑20 UNF pressure connection, compatible with brazed or capillary fittings common in commercial refrigerant systems. As a dual‑channel switch with two independent SPDT contacts, it provides coordinated protection on both the suction and discharge sides, helping prevent compressor damage due to under‑ or over‑pressure conditions. Typical applications include protection of compressors in refrigeration and air‑conditioning systems where precise dual‑pressure monitoring and reliable auto reset are required.