51
20068423
GB
Maintenance
Combustion
If the combustion values found at the start of the intervention do
not satisfy current standards or anyway indicate a poor state of
combustion (consult the table below), contact the Technical As-
sistance Service for the necessary adjustments.
Tab. S
7.2.3
Measuring the ionisation current
The burner is fitted with an ionisation system to check that a
flame is present.
The minimum current for control box operation is 4 µA. The Op-
erator Panel visualises “30%” (see
parameter no. 954).
The burner provides a much higher current, so controls are not
normally required.
However, if it is necessary to measure the ionisation current, dis-
connect the plug-socket on the ionisation probe cable and insert
a direct current microammeter with a base scale of 100 µA - see
Fig. 39.
7.2.4
Checking the air and gas pressure on the
combustion head
To carry out this operation a pressure gauge must be used to
mesure the air and gas pressure at the combustion head, as
shown in Fig. 40.
EN 676
Air excess
CO
Max. output
1.2
Max. output
1.3
GAS
Theoretical
max. CO
2
0 % O
2
CO
2
% Calibration
mg/kWh
= 1.2
= 1.3
G 20
11.7
9.7
9
1000
G 25
11.5
9.5
8.8
1000
G 30
14.0
11.6
10.7
1000
G 31
13.7
11.4
10.5
1000
WARNING
Carefully check the polarities!
Fig. 39
D8154
+
_
_
+
D8155
Checking
air pressure
Checking
gas pressure
Fig. 40
