10
ADJUSTMENTS PRIOR TO IGNITION
THE FIRST IGNITION MUST BE CARRIED
OUT BY QUALIFIED PERSONNEL WITH THE
RIGHT INSTRUMENTS.
The adjustment of the combustion head, air,
was described on page 8.
In addition, the following adjustments must also
be made:
- open manual valves up-line from the gas
train.
- Adjust the minimum gas pressure switch to
the start of the scale (A).
- Adjust the air pressure switch to the start of the
scale (B).
- Purge the air from the gas line.
Continue to purge the air (we recommend
using a plastic tube routed outside the build-
ing) until gas is smelt.
- Assemble a pressure gauge (C) on the gas
pressure socket of the pipe coupling.
The manometer readings are used to calcu-
late MAX. burner power using the tables on
page 6.
- 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 delivery at the minimum.
SERVOMOTOR (D)
The servomotor provides simultaneous adjust-
ment of the air damper, by means of the variable
profile cam and the gas butterfly valve.
The angle of rotation of the servomotor is equal
to the angle on the graduated sector controlling
the gas butterfly valve.
The servomotor rotates through 90° degrees in
24 seconds.
Do not alter the factory setting for the 4 cams;
simply check that they are set as indicated
below:
Cam I
: 90°
Limits rotation toward maximum position. When
the burner is at max output, the gas butterfly
valve must be fully open: 90°.
Cam I I
: 0°
Limits rotation toward the minimum position.
When the burner is shut down, the air damper
and gas butterfly valve must be closed: 0°.
Cam I I I
: 15°
Adjusts the ignition position and the MIN output.
Cam I V
:
Integral with cam III
BURNER START-UP
Switch off the remote controls and place the
switch 1)(E) in position “MAN”.
As soon as the burner starts, check the direction
of rotation of the fan blade, looking through the
flame inspection window 17)(A)p.4. Make sure
that the lamps or testers connected to the sole-
noids, or pilot lights on the solenoids them-
selves, indicate that no voltage is present. If
voltage is present, stop the burner immediately
and check the electrical connections.
BURNER IGNITION
Having completed the checks indicated in the
previous heading, ignition of the burner should
be achieved. If the motor starts but the flame
does not appear and the control box goes into
lockout, reset and wait for a new firing attempt. If
ignition is still not achieved, it may be that gas is
not reaching the combustion head within the
safety time period of 3 seconds. In this case,
increase gas ignition delivery. The arrival of gas
to the pipe coupling is shown by the pressure
gauge (C). Once ignition has taken place, pro-
ceed with global calibration operations.
(A)
(C)
(D)
MIN GAS PRESSURE SWITCH
AIR PRESSURE SWITCH
(B)
SERVOMOTOR
D3855
D3854
D3841
D7679
(E)
D3833
In the event of a burner lockout, more than two consecutive burner reset opera-
tions could cause damage to the installation. On the third lockout, contact the Af-
tersales Service.
If further lockouts or burner faults occur, interventions must only be made by
qualified, authorised personnel (as indicated in this manual, and in compliance
with the laws and regulations currently in force).
ATTENTION
