This genuine Lennox OEM part is engineered to break the electrical circuit to the blower motor and control board immediately upon the removal of the service panel

making it suitable for both pressurized HVACR lines and above-ground potable water supply systems

clogged filters

verifying airflow across the heat exchanger and checking for a restricted filter is essential before installing this automatic reset limit switch

Trane CNT1220 Limit Switch This genuine Lennox OEM partThe Trane CNT1220 (officially updated to CNT01220) is a high limit thermal safety control engineered for precise HVAC over temperature protection. Designed as a direct OEM replacement part, this 160F auto limit switch monitors the supply plenum temperature to prevent heat exchanger damage or unsafe operating conditions. Utilizing a normally closed SPST (Single Pole Single Throw) contact configuration, it interrupts the gas valve or heating circuit