20052068
20
GB
Installation
4.8
Combustion head adjustment
At this point of the installation, the combustion head is fixed to the
boiler as shown in Fig. 13.
It is therefore especially easy to adjust, and this adjustment de-
pends only on the maximum output of the burner.
Two adjustments of the head are foreseen:
➤
air adjustment
➤
gas adjustment
In the diagram of Fig. 14, find the notch at which to adjust both air
and central gas/air.
4.8.1
Air adjustment
Rotate the screw 2) (Fig. 15) until the notch you have found corre-
sponds with the front surface 1) of the flange.
4.8.2
Gas adjustment
When the burner is working at the maximum output
≤
5680 MBtu/
hr fit the discs 1) and 2)(Fig. 16), supplied as part of the standard
equipment, removing the internal tube 3)(Fig. 16).
If the mains gas pressure is low, the head can be left in the stan-
dard set-up, limiting the modulation minimum to 1970 MBtu/hr.
Example:
Burner output = 6000 MBtu/hr
The diagram of Fig. 14 shows that the adjustments for this potential
is external air R1 = notch 3.
NOTE:
The diagram indicates the optimum adjustment for a type of boiler
according to Fig. 5.
The adjustments indicated can be modified during the initial start-
up.
Fig. 14
D10512
N
o
tc
h
Burner output
CAUTION
To facilitate adjustment, loosen the screw 3)
(Fig. 15), adjust and then lock.
Fig. 15
D9279
1
3
2
Fig. 16
D8084
