the underlying airflow or venting issue must be corrected

Universal Locking Design: Prevents unauthorized setpoint adjustments

ensuring proper electrical and mechanical alignment

technicians recommend installing a new gasket whenever the head assembly is removed to ensure a positive seal and prevent unexpected system downtime

Built to meet stringent UL 1585 and NEMA standards

MARS 39220 Limit Switch the underlying airflow or ventingThe MARS 39220 Limit Switch is a versatile, high reliability solution for field service technicians needing an exact or universal replacement for furnace high limit applications. This adjustable snap disc thermostat features a temperature range of 135F to 175F with a fixed 40F differential, allowing for precise calibration to match specific internal plenum requirements. Designed as an open on rise safety device, the 39220 ensures the heating circuit