Lennox 12Y80 Sequencer 320735-701 it prevents dry-firing and protects

it prevents dry-firing and protects the heat exchanger from thermal stress

moisture exposure in the blower compartment

Secure Manual Reset: Prevents automatic recycling after a fault

or visible cracks in the translucent plastic body of the trap

Lennox 12Y80 Sequencer 320735-701 it prevents dry-firing and protectsThe Lennox 12Y80 Sequencer (OEM part number 104284 03) is a critical thermal sequencer relay used to manage staged heating in Lennox electric furnaces and air handlers. As a DPDT normally open component, it acts as a timing controller for 24V circuits, ensuring that heating elements and blower motors activate in a staggered sequence. This staged operation is vital for preventing massive inrush current and potential electrical overload on the job site.