🔍 Key Concepts

• Photoelectric cell function in burner management systems • Difference between detecting flame presence vs. flame failure • How an automatic fuel shutoff is triggered in case of flame loss

💭 Think About

• Ask yourself: does the photoelectric cell directly move mechanical parts, or does it send an electrical signal to a control circuit? • Consider what a photoelectric cell actually senses: is it visible light from the flame, infrared from refractory, or just temperature? • Think about safety: in a flame failure, what should happen automatically to the burner circuit and fuel supply?

✅ Before You Answer

• Verify which option correctly describes what the cell senses (flame light vs. refractory heat vs. temperature). • Check which choice properly describes an electrical control action, not a mechanical linkage. • Eliminate any option that would reduce safety, such as bypassing a flame safeguard at any firing rate.