Adjustment Prior To Ignition; Servomotor - Riello RS 25/M BLU Installation, Use And Maintenance Instructions

MIN GAS PRESSURE SWITCH
(A)
(C)

SERVOMOTOR

(D)
AIR PRESSURE SWITCH
D3855 (B) D3854
D3841
D7679
10
ADJUSTMENTS PRIOR TO IGNITION
ATTENTION
THE FIRST IGNITION MUST BE CARRIED
OUT BY QUALIFIED PERSONNEL WITH THE
RIGHT INSTRUMENTS.
ATTENTION
Refer to paragraph "Safety test - with gas ball
valve closed" on page 17 before the first
start-up.
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