QRA4.U Siemens UV Flame Detector
$246.76
The Siemens QRA4.U is a UV flame detector for monitoring gas and oil flames in intermittent burner operation.
5 in stock
Description
- Designed for Intermittent Operation: Engineered specifically for burners that cycle off at least once every 24 hours, enabling essential automatic safety self-tests of the internal UV tube during routine start-up and shut-down sequences.
- Universal Gas, Oil, and Dual-Fuel Compatibility: Optimally tuned to detect ultraviolet spectral emissions across a wide variety of fuels—including natural gas, propane, light/heavy oil, and dual-fuel combinations—without requiring separate sensors or recalibration.
- Critical Combustion Safety Protection: Serves as a vital primary safety interlock, immediately identifying flame failures or flame loss to trigger fast safety shut-offs, mitigating the risk of furnace explosions and unburned fuel buildup.
Documentation
Technical Specifications
| Part Number | QRA4.U |
|---|---|
| Manufacturer | Siemens Combustion |
| Type | UV Flame Detector |
| Application | Flame Detection |
| Series | QRA |
| Size / Rating | Normal Sensitivity |
| Compatibility | Siemens burner controls |
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Description
The Siemens QRA4.U UV Flame Detector is a high-sensitivity optical flame sensor engineered for reliable combustion monitoring on gas, oil, and dual-fuel burners in intermittent operation. Built with a rugged, heat-resistant housing, the QRA4.U detects the ultraviolet radiation emitted by combustion flames, sending real-time signal feedback to compatible Siemens burner control units. By rapidly verifying flame presence during startup and firing cycles, this industrial flame safeguard prevents dangerous unburned fuel accumulation, ensuring maximum operational safety and system efficiency across commercial heating and process heating applications.
Frequently Asked Questions
What does "intermittent operation" mean for the Siemens QRA4.U?
Intermittent operation means the burner system must shut down automatically at least once every 24 hours. This brief interruption allows the burner control unit to test the QRA4.U UV tube for internal faults or aging before the next ignition cycle.
Can the Siemens QRA4.U detect both natural gas and oil flames?
Yes, the QRA4.U detects the narrow ultraviolet light band emitted by gas, liquid fuel (oil), and dual-fuel combustion flames, making it highly versatile for multi-fuel commercial burner systems.
Which Siemens burner controls are compatible with the QRA4.U UV detector?
The QRA4.U integrates with various Siemens burner management systems and flame safeguards designed for intermittent service, such as the LME, LMO, or LMV series, depending on the control panel voltage and system specifications.
How do you properly mount and position the Siemens QRA4.U flame sensor?
The detector mounts directly onto the burner sighting tube using its threaded connection adapter. It must be aimed directly at the primary ignition area (root of the flame) with a clear line-of-sight, free from obstructions or excessive ambient infrared interference.
How often should the UV sensor element in the QRA4.U be inspected or replaced?
Routine inspection and cleaning of the optical glass lens should occur during standard annual burner maintenance. Because UV photo cells degrade naturally over time (typically around 10,000 operational hours), regular signal testing and timely tube replacement are essential for preventing nuisance shutdowns.
