Siemens Oxygen Sensor ( QG020.000D27 )

Energy Combustion, Ahmedabad India Importer and suppliers of all accessories for Siemens Burner Managment Systems. The Siemens QGO20.000D27 is a specialized zirconium dioxide oxygen (O2) sensor used for combustion optimization in industrial burner systems. It measures the residual oxygen content in flue gases to help burner controls (like the LMV52) adjust the fuel-air ratio for maximum efficiency. Full Technical Specifications Feature Specification Measuring Principle Zirconium dioxide ($ZrO_2$) ion conductor Measuring Range 0.2 to 20.9% O2 Mains Voltage (Heater) AC 230 V ±15% (50–60 Hz) Power Consumption Max. 90 W (typically 35 W once regulated) Flue Gas Temperature Max. 300 °C at the measuring point Cell Operating Temp 700 °C ±50 °C (internally heated) Protection Rating IP40 (when installed correctly) Permitted Fuels Natural Gas (H), Light Fuel Oil (EL) Weight Approx. 0.9 kg Mounting Flange installation (often with AGO20 flue gas collector) Key Features & Operation Oxygen Trim Control: When paired with an LMV52 burner control and a PLL52 O2 module, it allows for "O2 trim," which automatically compensates for changes in air pressure, temperature, or fuel quality. Self-Heating: The sensor includes an internal heating element to bring the zirconium dioxide cell to its required operating temperature ($700$ °C). Construction: It features a stainless steel sensor tube and a die-cast aluminum connecting head. It is resistant to the aggressive substances typically found in gas and light oil flue gases. Service Life: This is a wearing part. Its lifespan depends on the flue gas composition (sulfur, silicon, and heavy metals like lead can shorten its life). Wiring and Connection The QGO20 requires a shielded 6-core cable for signal transmission. It is recommended to use twisted-pair wiring (e.g., LifYCY 3 x 2 x 0.2) to prevent electrical interference. B1/B2: Signal from the measuring cell and thermocouple. Q4/Q5: Mains power for the sensor heating element. Note: The shielding must be connected to the GND terminal of the PLL52 module, not to the protective earth. Maintenance & Installation Notes Orientation: The sensor should be installed horizontally or vertically, but never in a way that allows condensation to collect in the sensor tube. Heating Phase: Upon first commissioning or after a long shutdown, the sensor should be powered on for approximately 2 hours before the burner is started to allow it to reach thermal equilibrium. Forbidden Substances: Avoid fuels containing silicon, halogens, or heavy metals, as these will "poison" the zirconium cell and cause premature failure.