Lochinvar & A.O. Smith 100109908 Flame Sensor 320819-301 The Over-Pressure Protection Device (OPD)

The Over-Pressure Protection Device (OPD) is a safety mechanism required for regulators used on piping systems with inlet pressures exceeding 2 PSI (up to 5 PSI) to protect downstream equipment in the event of a regulator failure

color codes signify specific temperature ratings

though it is typically factory-configured for Natural Gas

Fail-Safe Operation: The manual reset with power outage feature ensures that critical low-water conditions are addressed by a technician before the burner resumes operation

Lochinvar & A.O. Smith 100109908 Flame Sensor 320819-301 The Over-Pressure Protection Device (OPD)The Lochinvar & A. O. Smith 100109908 Flame Sensor is a critical OEM replacement part designed for precise flame rectification in high efficiency water heaters and boilers. As a seasoned tech, you know that a failing flame sensor rod is the primary culprit behind intermittent data signals and "no flame detected" lockouts. This genuine factory part (formerly identified as part number 9004520215) ensures the flame sensing circuit maintains the microamp