As a direct HD54FK652 replacement

internal orifice sizing and spring rates are optimized for R22/R407C pressures

Does this assembly include the primary mounting hardware

If the switch is open and the reset button is engaged

preventing dust and debris from compromising the internal races

Lennox 80K89 Limit Switch 320788-702 As a direct HD54FK652 replacementThe Lennox 80K89 Limit Switch is a critical safety component designed for precise thermal regulation within residential gas furnaces. Engineered as a 150 180F AUTO Limit Switch, this L180 30F thermal cutout ensures the burner assembly shuts down if internal temperatures exceed the 180F threshold, preventing heat exchanger damage. Once the plenum cools by approximately 30F, the switch automatically resets, restoring normal furnace cycles. This Lennox