20016967
10
GB
WARNING
³
Tighten the screws (7) completely (without locking them); then lock them with a torque wrench setting of
3-4 Nm.
³
Check there are no gas leaks from the screws during these operations.
³
If the pressure test point (11) should work loose, it must be correctly fixed ensuring that the hole (F)
inside the head assembly (1) is facing downwards.
4.3
AIR DAMPER SETTING
,
(see fig. 9, page 9)
Do not carry out the first ignition with the air damper lower than set point 1.
The air damper leaves the factory set for minimum output.
To vary the setting proceed as follows:
³
Loosen the nut (9) and the screws (8).
³
When the burner shuts down the air damper closes automatically until a max. chimney depression of 0.5
mbar is reached.
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 con-
trol box operation is 5 µA.
The burner normally supplies a higher cur-
rent value, so that no check is needed. Any-
way, if you want to measure the ionization
current, you have to open the connector
(CN1)
(see electrical scheme page 8) fitted
on the wire and insert a microammeter.
4.5
AIR PRESSURE SWITCH
Adjust the air pressure switch after having performed all other burner adjustments with the air pressure
switch set to the start of the scale. With the burner operating at the required power, slowly turn knob clock-
wise until burner locks out. Then turn the knob anti-clockwise by about 20% of the set point and subse-
quently check to see if burner has started correctly. If the burner locks out again, turn the knob anti-
clockwise a little bit more.
Attention:
As a rule, the air pressure switch must prevent the air pressure from lowering below 80 % of the adjustment
value as well as preventing the CO in the fumes from exceeding 1% (10,000 ppm).
To check this, insert a combustion analyser into the chimney, slowly close the fan suction inlet
(for example
with cardboard)
and check that the burner locks out, before the CO in the fumes 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
WARNING
D4631
+
_
SO
CN1
Fig. 10
