14
BURNER OPERATION
BURNER STARTING
(A) - (B)
Starting phases with progressive time intervals
shown in seconds:
• Thermostat/pressure switch TL closes.
After about 3s:
•
0 s :
The control box starting cycle begins.
•
2 s :
The fan motor starts. Servomotor (12)
starts, air damper opens in 1
st
stage position.
•
3 s :
The ignition transformer is connected.
The pump 3) sucks the fuel from the tank
through the piping 1) and the filter 2) and
pumps it under pressure to delivery. The pis-
ton 4) rises and the fuel returns to the tank
through the piping 5) - 7). The screw 6) closes
the by-pass heading towards suction and the
solenoid valves 8) - 9) - 10), de-energized,
close the passage to the nozzles.
22 s :
Solenoid valves 8) and 9) open and the
fuel is sprayed out through the nozzle, igniting
when it comes into contact with the spark. This
is the 1st stage flame.
•
29 s:
The ignition transformer switches off.
•
36 s:
If the control device TR is closed or has
been replaced by a jumper wire, the 2nd stage
solenoid valve 10) opens and the servomotor
moves the air damper to 2
nd
stage position
.
The starting cycle comes to an end.
STEADY STATE OPERATION
System equipped with one control device TR
Once the starting cycle has come to an end,set
0-auto-man
selector to auto the command of the
2nd stage solenoid valve passes on to the con-
trol device TR that controls boiler temperature or
pressure.
• When the temperature or the pressure increas-
es until the control device TR opens, solenoid
valve 10) closes, and the burner passes from
the 2nd to the 1st stage of operation.
• When the temperature or pressure decreases
until the control device TR closes, solenoid
valve 10) opens, and the burner passes from
the 1st to the 2nd stage of operation, and so on.
• The burner stops when the demand for heat is
less than the amount of heat delivered by the
burner in the 1st stage. In this case, the control
device TL opens, and solenoid valves 8)-9)
close, the flame immediately goes out. The
fan's air gate valve closes completely.
Systems not equipped with control device
TR (jumper wire installed)
The burner is fired as described in the case
above. If the temperature or pressure increase
until control device TL opens, the burner shuts
down (Section A-A in the diagram).
FIRING FAILURE
If the burner does not fire, it goes into lock-out with-
in 5 s of the opening of the 1st nozzle valve and 30
s after the closing of control device TL.
The control box red pilot light will light up.
UNDESIRED SHUTDOWN DURING OPERA-
TION
If the flame goes out during operation, the burner
shuts down automatically within 1 second and
automatically attempts to start again by repeat-
ing the starting cycle.
HYDRAULIC SYSTEM LAYOUT
1
Pump suction
2
Filter
3
Pump
4
Pressure governor (with cut-off system)
5
Return pipe
6
By-pass screw
7
Pump return
8
Safety solenoid
9
1st stage valve
10 2nd stage valve
11 Filter
M
Pressure gauge
V
Vacuometer
(B)
(A)
5
6
2
3
4
M
V
8
9
10
11
1°
2°
7
1
Off
Yellow
Green
Red
For further details see page 15.
*
LED
RMO
*
D3950
LED
RMO
*
D3394
D3395