68
Unit powered, setup and commissioned
burner switch
closed?
pcv less than
cut-in?
PPC4000
Sequence of
Operation
Servos in closed position, P00, operating control relay
open, safety relay can be closed, low fire output on
Close operating control relay
Wait for profile
select
Wait for HIGH
purge request from
flame safeguard
Move servos to pre-purge position
Send purge position proved / high fire switch (8)
output to flame safeguard
Assume using HIGH, LOW
and AUTO output signals
from flame safeguard
Terminal M from flame
safeguard is used for
profile select
Wait for LOW fire start
request from flame
safeguard
Turn off high fire switch output (8)
Send low fire start signal (D) to flame safeguard
HIGH and AUTO
are OFF
To page
2
State 01
Revision 1.4
State 02
After State 01 and
throughout the cycle – If
Burner Switch Off or Profile
input lost or PCV above cut-
out, go to State 17 and
shutdown.
Throughout cycle, monitor
all digital inputs. Recycle
or Lockout as necessary.
State 03 to State 06
reserved for future –
valve proving
STANDBY
WAIT FOR PURGE
MOVE TO PURGE
State 07
State 08
PURGE
State 09
MOVE TO IGNITION
State 10
NO
NO
YES
YES
NO
NO
NO
YES
YES
Wait for servos to move to
pre-purge position, P01
Wait for servos to reach
Ignition position, P02
NO
NO