Siemens Flame sensor QRB1B-A048B70B

This is a Siemens flame detector and photosensor for diesel fuel or fuel oil burners. It uses photoelectric flame monitoring and is designed for boilers, heat generators and burner devices. The detector has a heat-resistant plastic housing and is built into burner equipment, and it is compatible with Siemens burner controls. It sends a signal to the burner control, with high sensitivity and fast response to flame loss, so it provides accurate flame monitoring.

Flame sensors of this type are selected by detection principle, response time, cable length and connector type, and the mounting thread or sleeve. The sensor must have a direct line of sight to the flame, so confirm the optical window is positioned correctly and the mounting arrangement matches the burner. Verify compatibility with the burner control model before ordering, and ensure the wiring and mechanical fixing are correct at installation.

Typical failures are a contaminated optical window, an aged sensor cell with a weakened signal, or a broken sheath. When the sensor no longer reports a flame, the burner control locks out and interrupts fuel supply after the safety time, often causing the burner to start and then shut down immediately. If the problem persists after replacing the sensor, check the burner control and wiring connections.