Burner Calibration (Light Oil Operation); Servomotor - Riello RLS 190/M MZ Installation, Use And Maintenance Instructions

SERVOMOTOR

(A)
BURNER CALIBRATION (light-oil operation)
N.B.
It is advisable to first set the burner for operating
on oil and then for gas.
WARNING
Execute the fuel exchange when the burner
is off.
FIRING
Set switch 1)(C)p.10 to "MAN".
During the first firing, during the passage from
the 1st to the 2nd stage, there is a momentary
lowering of the fuel pressure caused by the fill-
ing of the 2nd stage nozzle tubing. This lowering
of the fuel pressure can cause the burner to
lock-out and can sometimes give rise to pulsa-
tions.
Once the following adjustments have been
made, the firing of the burner must generate a
noise similar to the noise generated during oper-
ation.
D887
OPERATION
The optimum calibration of the burner requires
an analysis of the flue gases at the boiler outlet
and interventions on the following points.
• 1st and 2nd stage nozzles
See the information listed on page 6 and 7.
• Combustion head
The adjustment of the combustion head already
carried out (page 8) need not be altered unless
the 2nd stage delivery of the burner is changed.
• Pump pressure
12 bar: This is the pressure calibrated in the fac-
tory which is usually sufficient for most pur-
poses. Sometimes, this pressure must be
adjusted to:
10 bar in order to reduce fuel delivery. This
adjustment is possible only if the surrounding
temperature remains above 0 °C;
14 bar in order to increase fuel delivery or to
ensure firings even at temperatures of less than
0 °C.
In order to adjust pump pressure, use the screw
5)(B)p.10.
• 1st and 2nd stage fan air gate valve
See adjustments of servomotor.
SERVOMOTOR (A)
The servomotor provides simultaneous adjust-
ment of the air gate valve, by means of the
variable profile cam, and the gas butterfly valve.
The servomotor rotates through 130 degrees in
33 seconds.
Do not alter the factory setting for the 5 cams;
simply check that they are set as indicated
below:
Cam I
Limits rotation toward maximum position.
When the burner is at max output the gas butter-
fly valve must be fully open: 90°.
Cam II
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 III
Adjusts the ignition position and the MIN output.
Cam IV
Adjusts the ignition position and the 1st stage
output.
Cam V
Determines when the 2nd-stage diesel oil valve
opens.
11
: 130°
: 0°
: 30° (gas)
: 30° (oil)
: 90°