Lennox 73K21 Limit Switch 319847-401 Technicians should check for continuity

Technicians should check for continuity across the coil

facilitating precise sequencing with external equipment

ensuring reliable thermal dissipation in high-static environments

using a higher wattage element than specified can trip breakers or damage the internal wiring

Lennox 73K21 Limit Switch 319847-401 Technicians should check for continuityThe Lennox 73K21 Limit Switch is a critical safety component designed for precise thermal regulation within residential gas furnaces and air handlers. Engineered as a Lennox replacement part, this 145 175F AUTO limit switch monitors discharge air temperatures to prevent heat exchanger overheating. It operates on a normally closed circuit that opens if temperatures exceed the 175F threshold, effectively cutting power to the gas valve or ignition