Verify the specific furnace model number against the factory parts manual to confirm this is the correct technical specification for your system

and solid-state boards across multiple line voltages

The White Rodgers 3L09-17 is a board-mounted 1/2" bimetal disc limit switch engineered for precision thermal protection in HVAC systems

Replacing the older 100-402 or mercury-based Econostat models

ensuring electrical impedance and mounting alignment match original specifications

Maxitrol KMR212TL Top Loading Kit 30067439-890 Verify the specific furnace modelProfessional grade Maxitrol KMR212TL Top Loading Kit is an essential field replacement assembly specifically engineered for Maxitrol Selectra systems using MR212D, MR212E, and MR212G modulating regulator valves. Designed to maintain precise control in direct fired negative pressure burners, this kit ensures the atmospheric reference and vent sensing remain optimized for consistent burner performance. As a veteran verified solution for industrial gas