Adjustments Before Firing; Servomotor; Burner Starting; Burner Firing - Riello RS 28 Instrucciones De Instalación, Funcionamiento Y Mantenimiento

MIN GAS PRESSURE SWITCH
(A)
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(C)

SERVOMOTOR

(D)
Burner off
Burner on
(E)
AIR PRESSURE SWITCH
(B)
1 2
1st stage
2nd stage
ADJUSTMENTS BEFORE FIRST FIRING
Adjustment of the combustion head, and air and
gas deliveries has been illustrated on page 7.
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 zero
position 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.
- Fit a U-type manometer (C) to the gas pres-
sure test point on the sleeve.
The manometer readings are used to calcu-
late the 2nd stage operation burner power
using the tables on page 5.
- 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 gate valve, by means of the vari-
able 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 12 seconds.
Do not alter the factory setting for the 4 cams;
simply check that they are set as indicated
below:
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Cam St2
Limits rotation toward maximum position. When
the burner is in 2nd stage operation the gas but-
terfly valve must be fully open: 90°.
Cam St0
Limits rotation toward the minimum position.
When the burner is shut down the air gate valve
and the gas butterfly valve must be closed: 0°.
Cam St1
Adjusts the ignition position and the output in 1st
stage operation.
Cam MV

BURNER STARTING

Close the control devices and set:
• switch 1)(E) to "Burner ON" position
• switch 2)(E) to "1st STAGE" position.
As soon as the burner starts check the direction
of rotation of the fan blade, looking through the
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flame inspection window 18)(A)p.3.
Make sure that the lamps or testers connected
to the solenoids, or pilot lights on the solenoids
themselves, indicate that no voltage is present.
If voltage is present, then immediately stop the
burner and check electrical connections.

BURNER FIRING

Having completed the checks indicated in the
previous heading, the burner should fire. If the
motor starts but the flame does not appear and
the control box goes into lock-out, reset and wait
for a new firing attempt.
If firing is still not achieved, it may be that gas is
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not reaching the combustion head within the
safety time period of 3 seconds.
In this case increase gas firing delivery.
The arrival of gas at the sleeve is indicated by
the U-type manometer (C).
Once the burner has fired, now proceed with
global calibration operations.
12
: 90°
: 0°
: 15°
: not used