QRA4.U Siemens Detector

Overview

The Siemens QRA4.U is a high-performance ultraviolet (UV) flame detector specifically designed for the supervision of gas or oil flames and for ignition spark proving. Constructed with a durable aluminum housing, this sensor is engineered for intermittent operation in industrial and commercial burner systems. It utilizes a UV-sensitive cell that detects radiation in the 190 to 270 nm range, ensuring reliable flame monitoring while remaining insensitive to daylight or glowing firebrick in the combustion chamber.

Features

• UV-sensitive cell with two electrodes that trigger a current signal upon detecting 190 to 270 nm radiation
• Durable aluminum housing designed for direct mounting on burners or boilers
• Integrated 3/4 inch-14 NPSM connecting thread for secure mechanical installation
• Insensitive to infrared radiation, daylight, and glowing firebrick to prevent false signals
• Includes approximately 1.8 meters of connecting wire for flexible electrical integration
• Optional accessories available, such as thermal insulation glass (AGG02) and mounting couplings (AGG04)

Specifications

• Model: QRA4.U
• Detection Type: Ultraviolet (UV)
• Sensitivity: Normal
• Spectral Response: 190 to 270 nm
• Supply Voltage: Determined by compatible burner control
• Operating Temperature: -20 C to +60 C (-4 F to +140 F)
• Maximum Combustion Chamber Pressure: 150 mbar (2.17 PSIG)
• Protection Rating: IP54 (when properly mounted)
• Weight: Approximately 180 g (0.4 lb)
• Service Life: Average UV cell life of 10,000 hours at +50 C

Applications

• Supervision of gas flames and yellow or blue-burning oil flames
• Ignition spark proving in industrial burner systems
• Intermittent operation cycles in commercial heating and boiler applications
• Compatible with a wide range of Siemens burner controls, including LFL, LFE1, LMG, LMV2, LMV3, and LMV5 series