Riello G20 Installation, Use And Maintenance Instructions page 8

Combustion head settings indicated in the schedule are valid for most cases.
The setting of the fan output according to the installation should normally be done only through the air
damper. Should one subsequently want to retouch also the setting of the combustion head, with the
burner running, operate on the rod (1) with a 6 mm spanner (2) as follows:
TURN TO THE RIGHT: (sign
In order to increase the volume of air entering the combustion chamber and thus diminishing its
pressure. There is a reduction of CO
(Setting advisable for ignitions at low temperatures).
TURN TO THE LEFT:
In order to reduce the volume of air entering the combustion chamber and thus increasing its pressure.
improves and the adhesion of the flame to the diffuser tends to reduce. 
The CO
2
(This setting is not advisable for ignitions at low temperatures).
In any case do not bring the combustion head setting more than one point away from that indicated in
the schedule. One set-point corresponds to 3 turns of the rod; a hole (3) at its end facilitates counting
the number of turns.
2
1
6
4
AIR DAMPER ADJUSTMENT
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).
The settings indicated in the schedule are purely indicative.
Each installation however, has its own unpredictable working conditions: actual nozzle output;
positive or negative pressure in the combustion-chamber, the need of excess air, etc. All these
conditions may require a different air-damper setting.
20013653
+
)
and the adhesion of the flame to the air diffuser disc improves. 
2
(sign – )
3
D5285
D5231
6 GB
1
2