All Topics
Startup & Shutdown
Safe boiler startup sequence, normal shutdown, and emergency shutdown procedures.
In this topic:
Cold Startup Sequence
Starting a cold boiler requires a specific sequence to prevent thermal shock and ensure safety.
- 1. Verify water level is at the normal operating level
- 2. Open the vent valve (allows air to escape as steam forms)
- 3. Verify fuel supply is available and valves are in correct position
- 4. Check all controls: pressuretrol, LWCO, flame safeguards
- 5. Start the burner on low fire
- 6. Warm the boiler SLOWLY — avoid thermal shock
- 7. Close the vent valve when steam appears (positive pressure)
- 8. Monitor pressure rise — do not exceed MAWP
- 9. Test safety valve(s) when at 75%+ operating pressure
- 10. Put the boiler on line gradually — open the steam stop valve slowly
Opening steam valves rapidly causes water hammer in cold steam lines. ALWAYS open slowly.
Normal Shutdown
A controlled shutdown follows a safe sequence to cool the boiler gradually.
- 1. Reduce firing rate to low fire
- 2. Allow pressure to drop gradually
- 3. Close the steam stop valve when boiler is isolated from the header
- 4. Secure the burner
- 5. Maintain water level during cooldown
- 6. Open the vent valve once pressure drops below 5 psi to prevent vacuum
- 7. Do NOT drain the boiler hot — let it cool naturally
Emergency Shutdown
Emergency shutdown is performed when immediate danger exists.
- Secure the burner IMMEDIATELY
- Emergency conditions: low water, overpressure, flame rollout, tube rupture, fuel leak
- Do NOT add water to an overheated boiler
- Do NOT drain a hot boiler rapidly
- Notify supervision and document the incident
- Boiler must be inspected before returning to service
In any emergency, the FIRST action is always to secure the burner.