7
2736
GB
4.3 AIR DAMPER SETTING
The regulation of the air-rate is made by adjusting the air damper
(1)
, after
loosing the screws
(2)
.
When the optimal regulation is reached,
screw tight the screws (2)
.
4.4
COMBUSTION CHECK
It is advisable to set the burner according to the type of gas used and following the indications of the table:
IONIZATION CURRENT
The minimum current necessary for the control box operation is 3
μ
A.
The burner normally supplies a higher current value, so that no check is needed. However, if you want to measure
the ionization current, you must open the connector fitted to the red wire and insert a microammeter.
4.5
AIR PRESSURE SWITCH
The air pressure switch is set after all other adjustments have been made. Begin with the switch at the lowest
setting. With the burner working at the minimum output, adjust the dial clockwise, increasing its value until
the burner shuts down. Now reduce the value by one set point, turning the dial anti-clockwise.
Check for reliable burner operation, if the burner shuts down, reduce the value by a half set point.
Attention:
To comply with the EN 676 standard, the air pressure switch must operate when the CO value exceeds 1%
(10,000 ppm). To check this, insert a combustion analyser in the flue, slowly reduce the burner air setting and ver-
ify that the burner shuts down by the action of the air pressure switch before the CO value exceeds 1%.
EN 676
AIR EXCESS:
max. output
1.2
– min. output
1.3
GAS
Theoretical max. CO
2
0 % O
2
Setting
CO
2
%
CO
mg/kWh
NO
x
mg/kWh
= 1.2
= 1.3
G 20
11.7
9.7
9.0
100
170
G 25
11.5
9.5
8.8
100
170
G 30
14.0
11.6
10.7
100
230
G 31
13.7
11.4
10.5
100
230
1
D5231
2
2
Probe
Connector
Terminal board
of control-box
D5006
10