64
DIAGRAM OPERATION TWO PROGRESSIVE STAGES
Legend
T11
Air shutter opening time, from 0 to max.
TW
Begins with the closure of the thermostatic line
or the PG. The PA must be in the rest position.
This is the waiting and self-test time.
T10
Begins when the motor starts up and with the
pre-purge phase, within which the PA air
pressure switch must give the go-ahead.
T1
Pre-purge time.
T3
Pre-ignition phase, it ends when the gas valve
opens.
T2
Safety time, within which the flame signal must
reach the EC electrode.
T4
Interval between the opening of the gas valve
and the opening of the second stage.
T6
Air shutter closing time and program zero-setting
time.
T12
Time in which the air shutter shifts to the start-up
position.
EC
TR
MB
TC
PG
PA
VE
0
max.
min.
MT
M
TW
T11
T1
T12
T4
T10
T3
T2
T6
Input signals
Output signals
A
Begin start up
B
Flame present
B-C
Operation
C
Control stop
C-D
Air shutter c post-purge
TC-PG
Thermostats/Gas pressure switch line
MB
Burner motor
PA
Air pressure switch
TR
Ignition transformer
VE
Gas valve
EC
Control electrode
MT
Air servo control
