baltur BT 75 DSPG Manual User Instructions page 56

Operation: The previous diagrams show both the connection circuit and the control program from the allowed input signals
necessary for the burner command control section and the relative flame supervision circuit. If the necessary input
signals are not present, the burner control stops the start-up sequence at the points indicated by the symbols and
it locks it if it's required by Safety Standards. The symbols used are the same as the ones on the burner lockout
command indicator...
A Consensus for start-up (for example through system thermostat or "R" pressure switch.)
A-B Start-up program
B-C Burner standard operation (according to the "LR" load regulator controls)
C Controlled stop through "R"
C-D Programmer return to start-up position A, post-ventilation. During the regulation stops, the flame control circuit is
powered for the detector and the stray lights test.
Necessary conditions for the burner start-up Unblocked equipment:
- Programmer in start-up position (for LAL1 shown by the presence of voltage to terminals 4 and 11; for LAL2
shown by the presence of voltage to terminals 11 and 12).
- Air damper closed. The limit switch z for CLOSED position has to allow the voltage passage between terminal 11
and 8.
- The safety thermostat or W pressure switch contact and other safety devices connected to the start-up circuit
from terminal 4 to terminal 5 must be closed (i.e. fuel oil pre-heating temperature control contacts).
Additional for LAL2...;
- Any fuel valve seal control contact or any other contact with similar functions must be closed between terminal
12 and LP air pressure switch.
- The N.C. normally closed air pressure switch stand-by contact must be in stand-by position (LP test).
Start-up program
A R start-up control
(R closes the start-up control ring between terminals 4 and 5}.
The programmer starts up. In the meantime the fan motor receives power from terminal 6 (only pre-
ventilation) and, after t7, also terminal 7 fan motor or chimney fan (pre-ventilation and post-ventilation).
At the end of t16, the air damper open control passes through terminal 9;
during the air damper travel time, the programmer does not start up because
terminal 8, from which the programmer receives its voltage, is not powered. The
programmer re-starts only after the air damper complete opening.
t1 Pre-ventilation time with open air damper.
During pre-ventilation time the flame detection circuit dependability is checked and, in
case of malfunction, the equipment triggers a shutdown in lock condition.
With LAL2: Shortly after the beginning of pre-ventilation time the air pressure switch must switch from terminal 13 to terminal
14. If not, the equipment would trigger a shutdown in lock condition (the air pressure check starts up).
t3' Long pre-ignition time
(ignition transformer on terminal 15.)
With LAL1, the transformer is inserted on burner startup, while with LAL2 only after the LP pressure switch
switching which is, at the latest, at the end of t10.
At the end of pre-ventilation time, the equipment commands through terminal 10 the air
damper servomotor to flame ignition position, determined by auxiliary contact m. After a
few seconds the programmer motor is powered directly by the active part of the equipment.
Now terminal 8 doesn't matter any more for the continuation of the burner ignition.
22 / 32
98320_201302