🔍 Key Concepts

• water level electrode assemblies and how different probe lengths correspond to water level alarms (high, normal, low) • relationship between boiler normal water level and the position of the steam space vs. water space in the shell • how many electrodes are used for pump control (normal level band) versus high- and low-water alarms/trips

💭 Think About

• Look at the three vertical electrodes and compare their lengths to the letters B, C, D, and E. Which segment would represent the normal working band where the feed pump cycles on and off, rather than an extreme high or low? • In a typical automatic boiler water-level control, where would the control electrode(s) sit relative to the low‑water cutoff and the high‑water alarm? Match that to the vertical positions marked by the arrows. • Imagine the boiler steaming normally: you want some margin above the low‑water cutoff and below the high‑water alarm. Which lettered level best reflects that mid‑range operating level?

✅ Before You Answer

• Identify which electrode tip is at the lowest point (true low‑water cutoff / burner trip) and which is at the highest point (high‑water alarm). Eliminate those from your choices for normal level. • Confirm which part of the shell at arrow B likely represents the waterline entry area where water and steam separate. • Before choosing, be sure you are picking a level that provides operating margin both above the heating surfaces and below the steam space, not an extreme limit.