SUPCO Fixed Temp Auto Reset Plenum Mount 150-170F

Fixed-Temperature Limit Control

The SUPCO Fixed Temp Auto Reset Plenum Mount is a safety limit switch designed for HVAC air-handling systems. It opens the circuit when the plenum temperature rises above the set point and automatically resets once the temperature falls back within the defined range. This device suits technicians and installers fitting or servicing forced-air equipment that requires a primary or backup high-limit protector. It is not intended for applications needing adjustable trip points or manual-reset functionality.

Sustained Operation Behaviour

Under continuous exposure to elevated plenum temperatures the switch cycles at the fixed 150-170F range with a 20-degree differential. The auto-reset action restores the closed contact without user intervention once the sensed temperature drops sufficiently. The SPST contact set is rated for 15 amps at 120 volts and 10 amps at 240 or 480 volts, supporting sustained control-circuit duty across the listed voltage range. Installations requiring a latching lockout or a different differential must select an alternative control.

Plenum-Mount Interface Limits

The switch mounts directly into the plenum through an insertion probe measuring 3 1/8 inches in length. Overall housing dimensions are 1 7/16 inches high by 1 5/8 inches wide, requiring adequate clearance inside the ductwork for proper airflow across the sensing element. The device operates solely as a temperature-activated SPST switch and provides no fan-speed staging, communication protocol, or variable-temperature programming. Systems needing multi-stage sequencing or digital integration require additional controls.