🔍 Key Concepts

• Boiler water level electrode probes (shortest vs longest and what each one controls) • Relationship between normal operating range and the alarm/cutout levels • How water level moves in a boiler: between pump cut-in and cut-out points, not between alarm points

💭 Think About

• Look at which electrodes are the shortest and which are the longest. Which ones are most likely used for high‑water alarm and low‑low‑water cutoff? • For normal operation, should the water level be cycling between alarm points, or between the pump control points that are slightly above/below the normal level? • If the lowest probe is for burner/cutoff protection, and the highest is for overfill alarm, which two labeled levels enclose the region where it is safe and normal for the level to float up and down?

✅ Before You Answer

• Identify which letter corresponds to the highest alarm probe and which corresponds to the lowest safety cutoff probe; eliminate those from the normal band. • Confirm that the normal operating range is between the pump-on and pump-off electrodes, not at the extreme ends. • Make sure the pair you choose sits between the top and bottom safety electrodes shown in the illustration.