🔍 Key Concepts

• Boiler safety valve operation – how the valve opens and reseats as pressure rises and falls • Blowdown – the difference between the pressure at which the valve pops and the pressure at which it closes again • Mechanical issues vs. pressure‑control/adjustment issues in safety valves

💭 Think About

• Ask yourself: Which condition would most likely cause the valve to open and close rapidly instead of opening smoothly and then reseating? • Consider how each option would affect the pressure at which the valve opens and the stability of the valve once it has opened. • Think about whether chattering is more often linked to poor pressure‑setting control or to downstream piping problems.

✅ Before You Answer

• Identify which options directly change how much the pressure must drop before the valve closes (blowdown behavior). • Decide which conditions would cause unstable, rapid cycling of the disc on the seat instead of a clean pop and reseat. • Separate issues that mainly restrict flow (like obstructions) from those that affect the opening/closing characteristics of the valve.