Key
A Fuel aspiration line
B Fuel filter
C Fuel aspiration line gate
D Flow-stop solenoid valve
E Return line gate
F Return line
G Bottom valve
H Rapid on-off gate with remote control
L One-way check valve
WORKING CYCLE
When switched on the burner motor starts and the 15-second pre-ventilation phase begins. During this phase the ignition
transformer comes on and the inter-electrode arc is generated. Once pre-ventilation is over the fuel on-off valve opens
and the fuel starts flowing out of the nozzle thus igniting a flame. After another 10 seconds (post-ignition phase) the inter-
electrode arc is switched off. If the flame fails to appear within 10 seconds of the end of pre-ventilation the burner is shut
down. If the flame accidentally goes out during routine operation an automatic re-ignition sequence begins. Burner shu-
tdown is indicated by the boiler system warning light (20) and/or by the room thermostat indicator. Burner restart is effected
by pressing the reset button (20).
A
TA
TC
MB
VE
t1
TR
t3
FR
Key
FR
Photoresistance
MB
Burner motor
TA
Ambient thermostat
TC
Termostato caldaia
TR
Ignition transformer
VE
Fuel valve
D
G
B
C
t3n
TSA
t1
Prepurge time (15 sec.)
t3
Preignition time (15 sec.)
t3n
Postignition time (10 sec.)
TSA
Safety time (10 sec.)
H
D
1
3
4
6
11
12
- 24
-
H
L
F
E
A
C
B
Required input signals
Control signals
A
Start of startup sequence
B
Time of flame establishment
C
Operating position
D
Controlled shutdown by TA-TC
Fig. 4
Fig. 5