maintaining the same physical dimensions and pressure specifications

allowing it to interface with a wide range of DDC controllers

which provides higher insulation resistance and reduces the risk of electrical breakdown between the 277V and 24V sides

Designed as a high-reliability replacement part

MARS 39004 Switch maintaining the same physical dimensionsThe MARS 39004 is a professional grade 390 Series SPDT Changeover Switch designed for automatic seasonal transition in hydronic heating and cooling systems. Specifically engineered for fan coil units, this summer winter changeover switch manages thermostat logic based on water temperature, ensuring seamless climate control without manual intervention. It features a high reliability SL 8 thermostat enclosed in a sealed case for environment protection