13
ADJUSTMENTS BEFORE FIRST FIRING
Adjustment of the combustion head, and air and
gas deliveries has been illustrated on
page 9.
In addition, the following adjustments must also
be made:
- Open manual valves up-line from the gas train.
- Adjust the air pressure switch to the zero posi-
tion of the scale (A).
- Adjust the maximum gas pressure switch to the
start of the scale (B).
- Adjust the minimum gas pressure switch to the
start of the scale (C).
- Purge the air from the gas line.
Continue to purge the air (we recommend us-
ing a plastic tube routed outside the building)
until gas is smelt.
- Fit a U-type manometer (D) to the gas pressure
test point on the sleeve, (+) and to the combus-
tion chamber:
- pressure test point (-).
The manometer readings are used to calculate
the 2nd stage operation burner power using the
graphs on page 7.
- Connect two lamps or testers to the two gas
line solenoid valves VR and VS to check the
exact moment at which voltage is supplied.
This operation is unnecessary if each of the
two solenoid valves is equipped with a pilot
light that signals voltage passing through.
Before starting up the burner it is good practice
to adjust the gas train so that ignition takes place
in conditions of maximum safety, i.e. with gas de-
livery at the minimum.
SERVOMOTOR
The servomotor automatically adjusts the air
gate valve, enables the gas valves to open only
if the air gate valve is in the correct position and
establishes when the stage 2 gas valve will be
energized.
It makes a maximum rotation of 90° in 5s.
It is equipped with 7 cams, which can be adjust-
ed by 4 coloured levers. A graduated plate with 4
coloured sectors marks the lever operation point.
Blue lever
This lever sets the position of the air gate valve
3)(A)p.5 while the burner is at rest. It is factory-
set as shown in figure (A)p.14: lever on axis 1.
The air gate valve is therefore kept fully closed
when the burner is at rest, to minimize heat loss
caused by flue draught.
If instead the air gate valve is to be kept partly
open while the burner is at rest (e.g. to cool the
combustion head), turn the blue lever to the left
(+ sign on the plate). The new air gate position
may be checked after starting and stopping the
burner. Do not, however, go beyond the position
of the orange lever, which sets the position of the
air gate valve in stage 1.
To return the air gate valve to the fully closed po-
sition with the burner at rest, turn the blue lever
to the right (- sign on the plate) to the position in-
dicated in figure (A)p.14: lever on axis 1. In this
case the air gate valve follows lever movement.
All the installation, mainte-
nance and disassembly opera-
tions must be carried out with
the electricity supply discon-
nected.
The installation of the burner
must be carried out by qualified
personnel, as indicated in this
manual and in compliance with
the standards and regulations
of the laws in force.
(D)
U-TYPE MANOMETER
D3441
(C)
D896
D66
D68
MIN GAS PRESSURE SWITCH
AIR PRESSURE SWITCH
MAX GAS PRESSURE SWITCH
(A)
(B)
DANGER
WARNING
Summary of Contents for GAS 9/2
Page 2: ......
