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Technical description of the burner
4.10 Burner description
1 Combustion head
2 Ignition electrode
3 Screw for combustion head adjustment
4 Pipe coupling
5 Minimum air pressure switch (differential type)
6 Flame sensor probe
7 Air pressure test point
8 Gas pressure test point and head fixing screw
9 Screw securing fan to sleeve
10 Slide bars for opening the burner and inspecting the
combustion head
11 Servomotor controlling the gas butterfly valve and the air
damper, by means of a variable profile cam mechanism.
When the burner is not operating the air damper is fully
closed in order to minimise heat dispersion from the boiler
due to the flue draught which draws air from the fan suction
inlet.
12 Plate with four hole knock-outs for electrical cable routing
13 Air inlet to fan
14 Gas input pipe
15 Gas butterfly valve
16 Boiler fixing flange
17 Flame stability disc
18 Flame inspection window
19 Plug-socket on ionisation probe cable
20 Motor contactor and thermal relay with reset button (RS 38
three-phase - RS 50)
21 Motor capacitor (RS 28 - RS 38 single-phase)
22 Control box with lockout pilot light and reset button
23 Two electric switches:
- one for “burner on - off”
- one for “1st - 2nd stage”
24 Plugs for electrical wiring
25 Air damper
Two types of burner lockout may occur:
CONTROL BOX LOCKOUT:
if the control box button (red LED) 22)(Fig. 4) lights up, it
indicates that the burner is locked out.
To reset, hold the pushbutton down for between 1 and 3 seconds.
MOTOR LOCKOUT (RS 38 three-phase - RS 50):
Release by pressing the button on thermal relay 20)(Fig. 4).
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