OPERATING CYCLE
A
B
B-C
C
C-D
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 lasting for 2,5 seconds.
T10 Begins when the motor starts up and withthe pre-purge phase; it lasts for 5 seconds,within which
the PA air pressure switchmust give the go-ahead.
T1 Pre-purge time, which lasts for at least 30 seconds, ending when the transformer starts up.
T3 Pre-ignition phase, it ends when the gas valve opens, and it lasts for 2 seconds.
T2 Safety time, within which the flame signal must reach the EC electrode; it lasts for 3 seconds.
UK
Necessary input signals
Output signals
Begin start up
Flame present
Operation
Control stop
Air gate closure + post-purge
TC-PG
Thermostats/Gas pressure
switch line
MB
Burner motor
PA
Air pressure switch
TR
Ignition transformer
V
Gas valve
EC
Control electrode
36
M