Startup, Normal Operation, and Shutdown Procedures
Core concepts
Packaged boiler start-up: verify water level and quality, confirm drains, vents, and valves are correctly lined up, prove interlocks and the flame scanner, purge the furnace with air flow proven, establish pilot, then main flame. Warm the boiler slowly and raise pressure per the manufacturer's schedule. Watch drum level as water expands; open the main steam stop slowly and warm the header with drains cracked. Avoid thermal shock from fast firing or rapid cooling.
Normal operation is mostly observation: level in the gauge glass, steam pressure, stack temperature, flue gas O2 and CO, fuel and feedwater flow, burner flame, and unusual noise. Routine tasks include blowdown, soot blowing at stable moderate load, water testing, and logging.
Shutdown: reduce firing gradually, hold level slightly high, blow down, close the main steam stop, and keep the boiler vented while cooling if it will be drained. For layup, choose wet storage (deaerated, chemically treated water, nitrogen blanket) or dry storage (desiccant).
Traps
Questions test the order of purge versus light-off, or whether to add water on low water. Purge always precedes pilot; never add water to a hot boiler when the level is uncertain.
Worked example
On a cold start, raise pressure at a rate the drum can tolerate - a common guideline is roughly 50 to 100 psi per hour for small packaged units; consult the manufacturer before assuming a rate for your boiler.