Honeywell Lead assy 45900414-004

This Honeywell lead assembly (45900414-004) is a thermocouple circuit breaker reserve (adapter) used in flame control systems of gas boilers, water heaters, and burners. It mounts between the thermocouple and the solenoid gas valve. In an emergency, it opens the electrical circuit, triggering the safety system to shut off the gas supply. The long reserve design accommodates extended distances to the valve. Supplied as a complete assembly with crimped connections and a long eco tip connector. Made in the USA or Europe.

When selecting a replacement of this kind, measure the distance between the thermocouple and the gas valve and compare the thread size and pitch. The 'long reserve' version provides extra thread length for deep mountings. Ensure the crimped connections are tight and corrosion-free. Route the lead away from hot surfaces and sharp edges to prevent arcing.

When these breakers fail, the burner may not hold flame or the gas valve may close unexpectedly. Common causes include a broken wire, corroded crimps, or damaged insulation. Check continuity with a multimeter and inspect the lead for wear, especially near the hot end.