Unigas N880X-FGR, Руководство по установке, использованию и обслуживанию, Страница: 32 / 60

PART III: OPERATION
32

Choose the type of fuel by turning the switch, on the burner control panel.
CAUTION: if the fuel chosen is light oil, be sure the cutoff valves on the feed and return pipes are open.

Check the control box is not locked; if so, reset it by means of the reset LMV button.

Check the series of thermostats and pressure switches allow the burner to start.
Gas operation

Choose the type of fuel by turning the switch, on the burner control panel.

Check that the control box is not in the lockout position (light B on); in case unlock it by pressing the relevant key (for further infor-
mation on the LMV5.., see the related manual).

Check that the pressure switches/thermostats series enables the burner operation.

Check that the gas pressure is sufficient (signalled by an error code on the AZL2.. display).

At the beginning of the start-up cycle, the actuator drives the air damper to the maximum opening position, then the fan motor
starts up: the pre-purge phase begins. During the pre-purge phase, the air damper complete opening is signalled by the light
F on
(see front panel).

At the end of the pre-purge, the air damper is driven to the ignition position, the ignition transformer is energised (signalled by the
light
H on the front panel) then, few seconds later, the EV1 and EV2 gas valves are energised (light L and I on the front panel).

Few seconds after the gas valves opening, the ignition transformer is de-energised and light H turns to off.

The burner operates in the low flame stage; few seconds later the two-stages operation begins and the burner output increases or
decreases, driven by the external thermostats (progressive burners) or by the modulator (fully-modulating burners).
.
Light oil operation

The fan motor starts and the pre-purge phase as well. Since the pre-purge phase must be carried out at the maximum air rate, the
control box drives the actuator opening and when the maximum opening position is reached, the pre-purge time counting starts.

At the end of the pre-purge time, the actuator is in the light oil ignition position: the ignition transformer is energised (lamp L on); the
ignitor gas valves and the light oil valves open. Few seconds after the valves opening, the transformer is de-energised and lamp L
turns off.

The burner is now operating, meanwhile the actuator goes to the high flame position; after some seconds, the two-stage operation
begins; the burner is driven automatically to high flame or low flame, according to the plant requirements.Operation in high or low
flame is signalled by LED
N on the burner control panel.