Common in top vent gas furnace repair

As a high-limit switch

A stuck sequencer often indicates a compromised internal thermal disk

allowing it to operate in any position

Operating with a 300-degree F trip point

McDonnell & Miller 326950 Junction Box Cover Els PW 17895 Common in top vent gasThe McDonnell & Miller 326950 Junction Box Cover is a precision engineered OEM replacement part designed for field technicians maintaining boiler control systems. This rugged component is specifically built for the McDonnell & Miller 42 and 150 Series low water cut offs and level controls, directly replacing Model Number 150 436. It provides critical protection for internal electrical connections, shielding terminal blocks and wiring from dust,