Lennox 57M67 Pressure Switch the stem extension should be

the stem extension should be threaded to a gauge height of 2-1/8 inches (54 mm)

ensuring the valve stem remains securely sealed without increasing mechanical friction that could lead to actuator hysteresis

Clear Calibration: Provided with high-visibility 60-90 degree inserts to ensure setpoint accuracy for facility operators

This pilot safety sensor is engineered to generate the necessary voltage to hold the gas valve solenoid open under standard operating temperatures

used to prevent overheating

Lennox 57M67 Pressure Switch the stem extension should beThe Lennox 57M67 Pressure Switch is a high precision OEM component engineered for critical safety monitoring in gas fired furnaces and HVAC systems. As a veteran technician knows, maintaining the correct pressure threshold is vital for inducer motor verification and combustion safety. This SPST pressure switch is factory calibrated to actuate at 1. 71" WC (water column), ensuring that the exhaust blower is moving sufficient air before the ignition