Lennox 66J78 Limit Switch Els PW 17895 A 70W heater is sized

A 70W heater is sized to maintain proper oil viscosity for specific compressor frames

and shuttering valves caused by mineral scale or mechanical wear

This 160F CO Auto Limit Switch acts as a critical safety benchmark

Broad Interchangeability: Replaces multiple previous versions

Lennox 66J78 Limit Switch Els PW 17895 A 70W heater is sizedExperienced HVAC contractors recognize the Lennox 66J78 Limit Switch as a critical safety component for maintaining furnace integrity and preventing heat exchanger damage. This OEM Lennox replacement part is a 36T series disc style control designed for High Limit or Secondary Rollout applications. It features a Normally Closed (NC) circuit that opens on temperature rise to interrupt the heating cycle if internal temperatures exceed safe operating