For technicians diagnosing a "4-flash" error code or an open limit circuit

While widely used in the L1RC residential furnace series

A resistored element like the SP10552MH helps equalize the electrical potential

Efficient Coil: Low-power 208/240V coil stays cool to prevent insulation breakdown

Built for versatility in high-demand residential split systems and mobile home air handlers

Lochinvar & A.O. Smith 100165930 Flame Sensor For technicians diagnosing a "4-flash"The Lochinvar & A. O. Smith 100165930 Flame Sensor is a critical OEM replacement part engineered for precise flame rectification in high efficiency heating systems. Designed specifically for the Lochinvar Knight series, including WH 55 through WH 399 and KH 55 285 fire tube boilers, this sensor accurately detects the burner flame to maintain combustion safety and fuel efficiency. It is a direct genuine OEM substitute for the PLT3022 and includes a