Lennox 73K21 Limit Switch 319847-401 This time delay relay kit

This time delay relay kit is the direct field-replacement for the obsolete Reznor 116044 and Thermodisc 12530305256 models

NEMA 4 models (such as the F261MFH series) provide a higher level of protection against dust and high-pressure water washdowns

Technicians should check for continuity across the coil

facilitating precise sequencing with external equipment

Does this board require specific programming in the field

Lennox 73K21 Limit Switch 319847-401 This time delay relay kitThe 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