Perform a continuity test across the terminals when the unit is cool

maintaining the integrity of the heater enclosure is vital for thermal efficiency and safety

or a "hard start" condition where the compressor hums but fails to turn over

designed to interrupt the burner circuit if internal plenum temperatures exceed safe operating parameters

Lennox 13W87 Run Capacitor Perform a continuity test acrossThe Lennox 13W87 Run Capacitor is a high spec 50 7. 5 MFD 440V dual rated component engineered for demanding condenser applications. As a veteran preferred Lennox OEM replacement part, this round dual run capacitor provides the critical phase shift required to stabilize compressor start up and maintain efficient condenser fan motor RPMs. Rated for 440VAC, it is backward compatible with 370V systems, offering superior dielectric strength and thermal