Start-up, Shutdown and Normal Operating Procedures
Core concepts
A safe start-up follows a sequence: pre-start checks, water level confirmation, safety valve and gauge checks, purge, light-off, warm-up, pressure raising, testing fittings, putting on line. Learn purge time and volume, warm-up rate, thermal stress, drum expansion, sliding feet and warming through connections.
Normal operation involves monitoring level, pressure, temperature, flue gas, feedwater, fuel supply, draft and blowdown schedule, plus log keeping. Shutdown may be normal, short-term standby or emergency. Understand cooling rate, draining, air flow and preservation (dry or wet lay-up).
Traps
- Skipping purge before light-off; unburnt fuel can explode.
- Raising pressure too quickly, causing thermal stress and leakage.
- Forgetting to drain superheater or to maintain air flow on shutdown.
- Assuming a boiler on standby needs no attention; level and frost protection still matter.
Worked rule of thumb
Allow a warm-up of roughly one hour per 1 000 kPa of pressure rise, or follow the manufacturer's rate, and never exceed the stated heating rate. A 700 kPa boiler therefore needs about 40–45 minutes minimum warm-up.