If the system fails to modulate or enter higher firing stages despite demand

In standard configurations

When performing a Lennox HVAC control board troubleshooting procedure

these 22 AWG leads can be lengthened up to 800 feet using shielded cable to maintain signal integrity in high-EMI environments

Operating as a direct-acting controller at 15 and 20 psig

Carrier P283-0380 Fan Relay 320735-701 If the system fails toThe Carrier P283 0380 Fan Relay is a specialized electromechanical switch designed for high cycle reliability in residential and commercial HVAC units. Featuring a 24V coil, this relay serves as the critical interface between low voltage thermostat controls and high voltage blower motor circuits. The SPNO SPNC (Single Pole Normally Open Single Pole Normally Closed) configuration provides dual circuit flexibility, allowing for the switching of