Specifically engineered for integration with Selectra Series 20

Common Questions How do I diagnose a failing Lennox 18G89 Flame Sensor

Standardized DIN Connection: Features a 24V DIN coil for rapid electrical swaps and improved moisture resistance

or diagonal—provided the flow direction matches the arrow on the body and the vent is protected from debris and moisture

When troubleshooting lockout codes or poor flame sensing

Lochinvar & A.O. Smith 100110973 Switch 318423-701 Specifically engineered for integration withThe Lochinvar & A. O. Smith 100110973 Blocked Flue Switch is a critical safety component designed for high efficiency boilers and commercial water heaters. As a veteran technician knows, this negative pressure switch (often referred to as a spill switch) is engineered to sense obstructions in the venting system, protecting the heat exchanger from hazardous flue gas recirculation. When the integrated sensor detects a lack of proper draft or a blocked