3313
7
GB
COMBUSTION ADJUSTMENT
In conformity with Efficiency Directive 92/42/EEC, the application of the burner on the boiler,
adjustment and testing must be carried out by observing the instruction manual of the boiler,
including verification of the CO and CO
2
concentration in the flue gases, their temperatures and
the average temperature of the water in the boiler. It is advisable to set the burner according to the
type of gas used and following the indications of the table:
IONISATION CURRENT
The minimum current necessary for the
control box operation is 5 µA.
The burner normally supplies a higher cur-
rent value, so that no check is needed.
Should you want to measure the ionisation
current anyway, you must open the con-
nector (
CN1
), (see wiring diagram page 5) inserted in the red wire and insert a microammeter.
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 function at the required power, turn the knob slowly in a
clockwise direction until burner lockout.
Then turn the knob anticlockwise to an extent that is around 20%
of the adjusted value and then check that the burner starts up
properly. If the burner locks out again turn the knob slightly in an
anticlockwise direction.
Attention:
In conformity with the standard, the air pressure switch must pre-
vent the air pressure falling below 80% of the adjusted value and
the CO in the flue gases exceeding 1% (10,000 ppm). To check
this, insert a combustion analyser in the flue, slowly reduce the
burner air setting (for example with a piece of cardboard) and verify that the burner locks out before
the CO value in the flue gases exceeds 1%.
EN 676
AIR EXCESS: max. output
λ
≤
1,2 – min. output
λ
≤
1,3
GAS
Theoretical max. CO
2
0 % O
2
Setting CO
2
%
CO
mg/kWh
NO
x
mg/kWh
λ
= 1.2
λ
= 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
D4625
+
_
Probe
Connector
Socket
of control-box
D7404
