🔍 Key Concepts

• Water level electrode assembly function in an automatic boiler control system • Which devices respond to low water level (safety shutdown) versus normal operating level (pump control) • Difference between pressure control (pressuretrol/pyrostat) and level control (feed pump / burner interlock)

💭 Think About

• Look at where the electrodes are positioned vertically: which ones would call for more water, and which would protect the boiler by shutting off heat? • Ask yourself: do the wires labeled "F" carry a signal related to water level or to steam pressure/temperature? • Which of the listed components must be directly interlocked to the water level so the boiler cannot fire under dangerous low‑water conditions?

✅ Before You Answer

• Verify that the leads marked F come from the individual electrode terminals at the top of the assembly, not from the boiler shell or pressure connections. • Confirm which of the answer choices are level‑sensitive devices (feed pump, burner safety interlock) versus pressure/temperature devices (pressuretrol, pyrostat). • Make sure your selected pair of devices would logically use separate electrodes at different levels inside the boiler for control and safety.