PART III: OPERATION
40
AIR FLOW AND FUEL ADJUSTMENT
Adjustments - brief description
Adjust the air and gas flow rates at the maximum output (“high flame”) first, by means of the air damper and the adjusting cam respec-
tively.
Check that the combustion parameters are in the suggested limits.
.Check the flow rate measuring it on the counter or, if it was not possible, verifying the combustion head pressure by means of a
differential pressure gauge.
Then, adjust the combustion values corresponding to the points between maximum and minimum: set the shape of the adjusting
cam foil. The adjusting cam sets the air/gas ratio in those points, regulating the opening-closing of the throttle gas valve.
Set, now, the low flame output, acting on the low flame microswitch of the actuator in order to avoid the low flame output increasing
too much or that the flues temperature gets too low to cause condensation in the chimney.
ADJUSTMENTS FOR GAS OPERATION
1
check the fan motor rotation.
2
Before starting the burner up, drive the high flame actuator microswitch matching the low flame one (in order to let the burner ope-
rates at the lowest output) to safely achieve the high flame stage.
3
Start the burner up by means of the thermostat series and wait until the pre-purge time comes to an end and that the burner starts
up;
4
drive the burner to high flame stage, by means fo the thermostat
TAB
.
5
Then move progressively the microswitch to higher values until it reaches the high flame position; always check the combustion
values and eventually adjusting the gas by means of the valves group stabiliser.
6
go on adjusting air and gas flow rates: check, continuosly, the flue gas analisys, as to avoid combustion with little air; dose the air
according to the gas flow rate change following the steps quoted below;
WARNING! During commissioning operations, do not let the burner operate with insufficient air flow (danger of
formation of carbon monoxide); if this should happen, make the fuel decrease slowly until the normal combustion
values are achieved.
WARNING! the combustion air excess must be adjusted according to the values in the following chart.
Recommended combustion parameters
Fuel
Recommended (%) CO
2
Recommended (%) O
2
Natural gas
9 ÷ 10
3 ÷ 4.8
Heavy oil
11 ÷ 12.5
4.2 ÷ 6.7
Summary of Contents for KP91
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