Siemens Flame Sensor QRA4.U

Product Details

Energy combustion,Ahmadabad importer and suppliers of siemens make flame sensor. The Siemens QRA4.U is a UV flame detector designed for intermittent operation (burners that shut down at least once every 24 hours). It is essentially the "US version" of the QRA series, featuring specific NPSM threading for pipe mounting directly onto the burner or boiler. Unlike the QRA53 or QRA75, the QRA4.U cannot be serviced—the UV cell is glued into the housing. If the cell fails, the entire unit must be replaced. Full Technical Specifications Feature Specification Detection Type Ultraviolet (UV) Spectral Sensitivity 190 to 270 nm Operating Mode Intermittent Operation only Sensitivity Normal (QRA4.U) or High (QRA4M.U) Mounting Thread ¾"-14 NPSM (for pipe/burner mounting) Conduit Thread ½"-14 NPSM (for protecting connecting wires) Cable Length Approx. 1.8 meters (stripped ends) Degree of Protection IP54 Temperature Range -20 °C to +60 °C Weight Approx. 180 g UV Cell Life Approx. 10,000 hours (at max +50 °C) Key Features Frontal Illumination: The sensor is designed to "see" the flame looking straight out of the front of the detector housing. Fuel Compatibility: Monitors gas flames, yellow-burning oil flames, blue-burning oil flames, and ignition sparks. It is also tested for "green fuel" blends like HVO. Housing Material: Durable die-cast aluminum, making it suitable for harsh industrial environments. Ignition Spark Proving: Highly sensitive to the UV radiation emitted during the ignition phase. Compatible Burner Controls The QRA4.U is a versatile sensor used with a wide range of Siemens controllers, often requiring an ancillary unit (like the AGQ1/2/3) depending on the control box: LFL / LAL / LME series LGB2... / LGB4... LMV2 / LMV3 / LMV5 (when configured for intermittent operation) Comparison: QRA4.U vs. QRA4M.U The "M" variant is the high-sensitivity version of this sensor. QRA4.U: Standard sensitivity for most gas and oil applications. QRA4M.U: High sensitivity, often used when the flame is very small, far away, or obscured by burner components. Installation Note Because the QRA4.U is sensitive to UV light, it can be "fooled" by other UV sources. Avoid mounting it where it might see halogen lamps, welding sparks, or X-rays, as these can cause a false "flame present" signal even when the burner is off.