Riello MB 405/1 Manuel D'entretien page 48

5 Activation, calibration and functioning
5.1 Notes on safety for the first start-up
The first start-up of the burner must be carried out
by qualified personnel, as indicated in this manual
and in compliance with the standards and regula-
tions of the laws in force.
WARNING
5.2 Factory presetting
The valve leaves the factory with the pressure adjuster regulated
to minimum.
Normally this calibration allows the burner to ignite, it is then ad-
justed as indicated in successive chapters. For the pressure val-
ue to set, refer to the manual "burner train combination" supplied
with the burner.
5.3 Adjustment of the pressure stabiliser
Calibrate the pressure adjuster by rotating the adjustment screw
using a screwdriver: by rotating clockwise there is an increase in
output pressure, by rotating anticlockwise there is a decrease in
pressure.
When the nominal desired pressure value has been reached,
close the cover and seal the extremities of the wire leaving the
passing ring short.
The greater the loss of pressure p between the inlet and the out-
let of the pressure stabiliser, the more effective its action; its func-
tionality increases with the increase in downstream pressure, as
an increment of obtainable pressure, compatible with the other
operational needs and with the network pressure availability, lim-
iting the opening of the upstream valve.
5.4 Valve adjustment
The slow ignition delivery (valve opening phase) should be ad-
justed, after having unscrewed the cover, by rotating the screw
below in the correct direction +/-; the cover itself may be used as
a tool by turning it upside down.
The steady state output is progressively reached starting from
the ignition delivery following the action of the hydraulic brake;
the steady state delivery may be adjusted by rotating the ring nut
6)(Fig. 1, page 4) in the appropriate direction + / – after having
loosened the unsealed screw 7).
5.5 Delivery optimisation
Optimal Multibloc functionality is achieved by first using the open-
ing of the valve and then adjusting the stabiliser to achieve the re-
quired delivery. If this is not obtained, repeat the operation
described above.
5.6 Low gas pressure switch adjustment
Please refer to the burner manual.
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Activation, calibration and functioning
10
Check the correct working of the adjustment, com-
mand and safety devices.
WARNING
If the burner goes into lockout without the formation of a flame
when started, check:
 the pilot light on the valve comes on
 connect a pressure gauge to the pressure test point
(between the valve and the combustion head) and check the
pressure during the lockout, if the pressure is too low, turn
the adjustment screw of the stabiliser clockwise 4)(Fig. 1,
page 4) by 1 turn and repeat the firing attempt.
5.3.1 Pressure couplings
Should the train be connected to power supply lines in which gas
may have a variable pressure coupling in accordance with the
calorific power of the gas, the stabiliser will need to be removed
using a dedicated kit.
In any case, where not already present, a maximum gas pres-
sure switch with manual reset must be fitted to the burner, elec-
trically connected in the thermostatic range and correctly
calibrated.
It is nonetheless preferable to calibrate this output by using the
upstream pressure of the stabiliser; the considerations made in
relation to the functionality of the pressure stabiliser already stat-
ed remain valid, optimal functioning of the valves is obtained
when they are fully opened: it is therefore necessary to seek the
best compromise between the requirements of the stabiliser and
of the valves.
GB