🔍 Key Concepts

• Photoelectric cell operation in boiler flame safeguard systems • Typical flame color and temperature in efficient oil burner combustion • Which part of the light spectrum is used for reliable flame detection and least affected by brickwork glow

💭 Think About

• Think about what color a healthy, efficient oil flame usually is near its root, not at the smoky tip. • Consider which spectral color would clearly indicate the presence of flame itself rather than hot furnace walls or brickwork. • Ask yourself: if the cell is looking for actual combustion, which part of the flame spectrum is both strong and distinct from background furnace radiation?

✅ Before You Answer

• Identify the typical visible color of a proper oil burner flame at the burner throat. • Distinguish between light from flame versus light from incandescent refractory brickwork. • Verify which spectral region (orange vs blue) is more closely associated with reliable flame presence detection in oil-fired boilers.