SIEMENS- M 99980-18875 Siemens Flame Sensor

Product Details

Siemens offers a comprehensive range of flame detectors categorized by their detection technology (UV, Infrared, or Photoresistive) and their operational mode (Intermittent or Continuous). The following guide breaks down the full details of the Siemens portfolio for industrial and commercial burners. 1. Technology Comparison Choosing the right sensor depends on the fuel type and the specific light spectrum emitted by the flame. Sensor Series Technology Best For... Light Spectrum QRA Ultraviolet (UV) Gas, Blue-burning oil, Ignition sparks 190–270 nm QRI Infrared (IR) Gas, Oil, Coal (High-heat signatures) Approx. 2 $\mu$m QRB Photoresistive Yellow-burning oil flames Approx. 600 nm RAR Selenium Photocell Oil flames (Heavy oil) Visible light 2. Operational Mode: Intermittent vs. Continuous Intermittent Operation: For burners that shut down at least once every 24 hours. These sensors (like QRA2 or QRB1) do not have built-in self-testing. Continuous Operation: For burners running 24/7. These sensors (like QRA53/55 or QRA7) feature a self-checking shutter that periodically blocks the sensor to ensure it hasn't failed in a "flame-on" state. 3. Detailed Series BreakdownQRA Series (Ultraviolet) Most common for gas burners. UV cells are highly precise but sensitive to "false" UV from welding or ignition sparks. QRA2 / QRA10: Standard for intermittent operation. QRA10 has a die-cast aluminum housing for tougher environments. QRA4: Designed specifically for the US market (NPSM threads). QRA53 / QRA55: Industrial self-checking sensors for continuous use. QRA7: Advanced digital UV sensor designed for the LMV5 burner management system. QRI Series (Infrared) Designed for large-scale industrial burners where the flame produces significant heat but might have low UV output. QRI2A: Frontal illumination (looks straight ahead). QRI2B: Lateral illumination (looks out the side at 90°). Key Feature: They ignore static heat (like glowing bricks) and only respond to the flicker frequency of an active flame. QRB Series (Photoresistive) The "budget-friendly" standard for residential and commercial oil burners. QRB1: Small, plastic housing with or without a plug. QRB3: Rugged version with a metal protective tube. QRB4: High-sensitivity version for yellow-burning oil. 4. Mounting & Accessories Siemens sensors often require specific accessories to protect the sensor from heat and debris: AGG06: Glass/Quartz holder for QRA10/QRA53 to protect the lens from soot. AGG02: Heat insulation glass for high-temperature applications. AGG16: Right-angle adapters for tight installation spaces. 5. Maintenance Checklist Cleaning: Use only a dry, lint-free cloth. Never use chemical sprays on the lens. UV Cell Life: Standard UV tubes (like in the QRA2) have a life of ~10,000 hours. If you get frequent "no flame" lockouts on an old sensor, the tube is likely exhausted. Safety: Always isolate the mains power before swapping a sensor, as some (like the QRA53) have internal high-voltage or motorized parts.