What causes this coil to fail in the field

this module provides field-selectable pre-purge timing (0 or 30 seconds) and adjustable trial for pilot ignition (15 or 90 seconds)

this mechanical temperature control monitors air or liquid temperatures and opens the SPDT switch when the temperature drops below the setpoint across any 1 foot of its 20-foot vapor-actuated sensing element

this component is engineered to resolve common pilot lighting issues and erratic temperature fluctuations found in older iterations

The upper thermostat (like the 100108951) manages the initial heating cycle and controls the ECO safety switch

Heil Quaker ICP 1184896 Limit Switch 322838-753 What causes this coil toThe Heil Quaker ICP 1184896 Limit Switch is a critical safety component engineered for forced air furnace applications. This L200 20F limit switch serves as a primary high limit control, designed to interrupt the burner circuit if the heat exchanger temperature exceeds safe operating parameters. Rated for a 200? F cutout and a 180? F cut in, this normally closed disc switch features an automatic reset mechanism that re establishes the circuit once