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

making it an essential item for any direct vent furnace repair kit

ensuring optimal compressor cycles and preventing system failure due to overheating

ensuring electrical impedance and mounting alignment match original specifications

For technicians servicing boilers or hydronic systems

Maxitrol KMR212TL Top Loading Kit 30067439-890 Replacing the older 100-402 orProfessional 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