VMP-IOMM-2018-2
Fulton Ltd
Page 40
OPERATION - 4
It is important in the combustion process to maintain proper air mixtures between the outer
surface and centre of the blast tube area. On most boilers the damper is locked in a wide
open position. However, if it is necessary to close the damper, care should be taken to close
the damper slowly and no more than one quarter of the distance of the swing of the damper
assembly.
A visual examination down the blast tube should reveal that no heat, flames or fumes are backing
up through the burner plate area. If they are, the secondary damper must be opened up once
again. Failure to remove the flame or gases from the blast tube area can cause a backfire as well
as cause premature failure of electrodes, flame rods, and other burner components.
A visual inspection down the burner view port should also show the fire completely covering
the furnace walls. If the fire is tunnelling down or is not to the outside wall of the furnace, the
efficiency will drop off. Close the secondary air damper until tunnelling stops.
The primary air adjustment or main air control is located at the fan housing face. This control
is used to supply the burner with excess air needed to facilitate good combustion. Too much or
too little air will result in poor combustion. It is important to make sure the lowest level of excess
oxygen is present while still maintaining a high level of carbon dioxide and negligible carbon
monoxide. Using a CO2 or O2 tester it is possible to determine the percent of excess air in the
combustion mixture.
It is a good policy on a gas fired unit to have between 3.5% and 4% oxygen present in the
combustion gasses. This will give you 9.5% to 10.5% carbon dioxide. The carbon monoxide level
should always be less than 100ppm (refer to local regulations).
4.3
PRIMARY AIR ADjUSTMENT (AUTO)
Figure. 20 -
Primary Air Adjustment on Burner
1. Switch OFF the electrical supply at the door isolator switch.
2. Isolate the supply lines of the fuel not required.
3. Open the isolation valve on the required fuel supply.
4. Switch the fuel selector switch to the required fuel.
5. Switch ON the electrical supply to the boiler at the door isolator.
6. Start the burner.
4.4
CHANGING TO THE ALTERNATIVE FUEL
DUAL FUEL BURNER
