York S1 026 39189 000 Fan Center Refrigerant This 24Vac spring return damper This 24Vac spring return damper features a two wire This Apollo water gauge set features a 1 2" NPT male connection and comes standard with 5 8" OD x 12" length glass this York fan center is frequently used by contractors to provide the necessary 24V control power and relay switching needed to integrate a cooling coil and thermostat into an older heating system The York S1 026 39189 000 Fan Center is a specialized HVAC control relay and transformer assembly engineered for high performance fan management in York residential and commercial air handlers