PART IV: OPERATION
28
Burner front panel
Gas operation
Check that the flame control is not in lockout position (signalling on LMV) and unlock it if necessary by pressing the dedicated but-
ton (for further information on the LMV.., see the relevant manual).
In the event of a burner blockage, always check that the pilot light (B6) for flame return blockage is off. If the light is on, it means
that the photocell has detected a flame inside the combustion head mesh.
In order to unlock the burner after a flame backfire warning lockout, it is necessary to switch off the power to the control panel
(necessary before inspecting the combustion head), wait a few seconds and then switch the power back on.
Finally, press the burner unlock button (S2).
Check that the gas pressure is sufficient (indicated by an error code on the AZL..display and PGMIN light on).
Verify that the set of pressure switches or thermostats gives operating consent to the burner.
Burners fitted with gas proving system:
the gas proving system test begins; when the test is performed the proving system LED
turns on. At the end of the test, the burner staring cycle begins: in case of leakage in a valve, the gas proving system stops the bur-
ner and the lamp
B1
turns on.
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
B2
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
B4
on the front panel) then, few seconds later, the EV1 and EV2 gas valves are energised (light G1 and G2 on the front
panel).
Few seconds after the gas valves opening, the ignition transformer is de-energised and light
B4
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).
DANGER!
Do not restart the burner without first inspecting the good condition of the combustion head according to the
maintenance chapter.
Keys
B1
Lock-out LED
B2
Hi-flame operation LED
B3
Lo-flame operation LED
B4
“Ignition transformer operation” LED
B5
“Fan motor overload tripped” LED
G1
“EV2 opening” LED
G2
“EV1 opening” LED
G3
“Gas pressure switch signal ” LED
S1
Main switch
S2
Reset pushbutton for control box
S3
Operation selector MAN - AUTO (operation in manual or automatic
mode):
MIN = operation with minimum output
MAX = operation at the maximum output
A1
Burner Modulator (only on fully modulating burners)
A2
AZL..
B2 B3
B4
B5
G1
G2
G3
B1
S2
S3
S1
B6
A1
A2
Summary of Contents for C70N US
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