Siemens Flame sensor QRB1B-A068B70B

This Siemens flame sensor is identified by SKU QRB1B-A068B70B and type designations 31070 and 31069. It belongs to the flame sensor category and is intended for burner control systems. The sensor monitors the flame presence during and after the ignition sequence.

Flame sensors of this type are chosen by matching the detection principle required by the burner control—ionisation, ultraviolet, or infrared—along with spectral range, response time, cable length, connector type, and mounting sleeve or flange. Before ordering, compare the electrical and mechanical interface with the existing control. During installation, position the sensor so it views the flame directly without obstruction.

Common failure modes for this sensor class include a contaminated optical window, an aged cell producing a weak signal, or a broken sheath or cable. When a failure occurs, the burner control does not receive the required flame signal within the safety time and may lock out. Inspect the sensor window for soiling and check the cable and sheath for damage.