Adjustment Prior To Ignition; Servomotor - Riello RS 44/M MZ Installation, Use And Maintenance Instructions

MIN GAS PRESSURE SWITCH
(A)
(C)

SERVOMOTOR

(D)
AIR PRESSURE SWITCH
D3855 (B)
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
D3854
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
D3841
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° in 24 seconds.
Do not alter the factory setting for the 4 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 I I
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 I I I
Adjusts the ignition position and the MIN output.
Cam I V
D790
10
WARNING
: 90°
: 0°
: 20°
: integral with cam III