MARS 39004 Switch this is the enclosure cover

this is the enclosure cover only

contractors can resolve gurgling noises and recurring drain pan clogs

supporting both heating and cooling cycles

The compact design and standard mounting flange allow for rapid integration into existing control strings

making it a staple for any HVAC repair kit

MARS 39004 Switch this is the enclosure coverThe 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