Boiler Light Off Notes
Before starting the boiler we walk down the boiler checking that valves are lined up and there is oil in the bearings and water in the sight glass also control air is on. the boiler setting is inspected for integrity and hatches are shut.
The addition of blowing down the boiler ensures that the water glass and remote indicators are working.
The addition of water ensures the economizer is purged of air bubbles and the feedwater pumps and valves are lined up.
These two practices are enlightened procedures for boiler start up for plants where the boilers have been off line for long periods and the state of remote indicators is unknown and boiler feed pump status is unknown. The temperature of the feedwater must also be considered before using these "enlightened" practices though the economizer tempers the incoming feedwater greatly.
To "light off," "start," or "initiate start sequence" the SA900 boiler we must start the fan with the damper in the closed position. We check that the boiler protective relays are reset high drum or level low drum level conditions must be corrected before the Boiler trip is resetable.
The fan damper is opened to the purge position 100% open and the furnace purge timer starts. when the purge is complete the damper is set to low fire position. The furnace ready light comes on.
The main gas is opened. (the duct burner gas valves must be shut and the fan must be on and no premissive voilation)
Once the gas pressure<min light clears the burner ready ready light comes on.
Push the duct burner start button turns on the ignitor and open the pilot gas shut off valves and pilot gas vent valve. When flame is detected the main gas valves open and the main gas vent valve shuts. The duct burner can trip due a boiler trip: low or high water, or a furnace trip: loss of fan or loss of flame detection and lastly pushing the burner stop button. Any burner trips cause the loss of burner firing signal, loss of burner premissives, gas shut valves closing, gas vent valve opening, and a burner purge.