Cleaver-Brooks - Complete Boiler Room Solutions

Boiler Startup and Shutdown in a Hot System

Tip Sheet: April 2017

Key Facts

  • Startup and shutdown steps differ depending on whether the system is hot or cold
  • In a warm system, when the pressure reaches 10 to 15 psig, close the boiler vent
  • In both conditions, manually test the safety valve for proper operation

Questions often arise as to the best practices for recommissioning a boiler that has been offline. Note that the procedures for starting up a boiler differ depending on whether the system is hot or cold. The below steps apply to boiler coming back online in a hot system. It also details the proper steps to shut down a boiler when others in the system remain operational.

Boiler Startup 

  1. Power the burner switch and prove the pilot and main flames.
  2. Check to see that the boiler vent and drain between the main stop valve(s) and the non-return valve are open. This is done to bleed any air from the system.
  3. If installed, open the equalizing valve around the main steam-stop valves.
  4. Open the main steam-stop valve(s).
  5. When the pressure reaches 10 to 15 psig, close the boiler vent.
  6. Test the low-water cutoff by securing the boiler feed and let the boiler steam off naturally to see if the switch cuts power to the burner at the proper low level.  If it does not, break power to the burner immediately and take corrective action.  With a positive result, reopen the boiler feed valve.
  7. Open the non-return valve when the steam pressure reaches 75 to 85 percent of the system-line pressure.
  8. Manually test the safety valve for proper operation and reseating.
  9. Bring up the boiler pressure slowly during low fire, allowing the non-return valve to automatically cut the boiler into the live system.
  10. Close the drain between the main stop valve(s) and the non-return valve.
  11. Verify that all automatic controls are operating properly.

Boiler Shutdown

  1. Power the burner off.
  2. Shut off the fuel to the burner.
  3. If equipped, open the superheater outlet drain valve.
  4. Close the main steam stop valve(s), and open all drains.
  5. Shut down the boiler feed system.

Next month’s Tip Sheet will detail boiler startup and shutdown procedures in a cold system. 

For more information, contact your local Cleaver-Brooks representative