Siemens UV Flame Detectors QRA4 Series

Siemens UV Flame Detectors QRA4 Series

Siemens QRA4 Series ultraviolet flame detectors are designed for supervising gas and oil burner flames in industrial combustion systems. They operate with compatible Siemens burner controls to monitor flame presence during burner operation.

Operating Principle

The Siemens QRA4 detects ultraviolet radiation emitted by gas or oil flames within the wavelength range of 190–270 nm. Its UV-sensitive cell responds to sufficient ultraviolet radiation by generating an electrical signal for the connected burner control.

The UV cell does not respond to daylight or glowing firebricks inside the combustion chamber. The detector is designed for flame supervision in intermittent operation.

Key Features

• Ultraviolet (UV) flame detection technology
• Suitable for gas flames and yellow- or blue-burning oil flames
• Supports ignition spark proving
• UV detection wavelength range of 190–270 nm
• Durable aluminum housing
• Frontal flame detection design
• IP54 protection when correctly mounted
• Available in normal- and high-sensitivity versions
• Compatible with selected Siemens burner control systems

Available Models

• QRA4.U: Normal-sensitivity UV flame detector
• QRA4M.U: High-sensitivity UV flame detector

Applications

The Siemens QRA4 Series is suitable for flame supervision in industrial boilers, gas burners, oil burners, industrial heating equipment, and combustion systems equipped with compatible Siemens burner controls.

Installation and Maintenance

The detector should be positioned to receive sufficient ultraviolet radiation from the flame. Detector wiring must be routed separately from other cables, particularly high-voltage ignition cables, to minimize electrical interference.

The UV cell is permanently fixed inside the detector housing and cannot be replaced separately. When the UV cell reaches the end of its service life, the complete flame detector must be replaced.

Important: Verify burner control compatibility and follow Siemens installation and safety instructions. Installation, wiring, and maintenance must be performed by qualified personnel.