11/15
Building Technologies Division
CC1N7418en
21.06.2016
Function
(cont´d)
If lockout occurs, the outputs for the fuel valves, the burner motor and the ignition
equipment are immediately deactivated (<1 second).
The lockout indication lamp changes to red and voltage is fed to terminal 10 (Alarm) for
remote lockout indication.
This state will also be maintained in the event of power failures.
Cause
Response of LGA41...
Response of LGA52... / LGA63...
Erroneous flame signal during «t1»
or «t3» (extraneous light)
Lockout ²) prior to the release of gas Lockout ²) prior to ignition and the
release of gas
No flame on completion of «TSA»
Lockout ²)
Lockout ²)
Loss of flame during operation
Repetition
Repetition
No air pressure signal during «t1»
---
No start
Air pressure failure during operation
---
Shutdown
²)
After lockout, the burner control can be reset after about 60...90 seconds
After lockout, the LGA will remain locked (lockout cannot be changed).
This state will also be maintained in the event of power failures.
After lockout, the burner control can be reset after 60...90 seconds (also refer to
Warning notes
).
The conductivity and rectifying effect of hot flame gases are used for flame supervision.
For that purpose, AC voltage is applied to the ionization probe which projects into the
flame. The current that flows in the presence of a flame (ionization current) generates
the flame signal which is then fed to the input of the flame signal amplifier. The amplifier
is designed such that it only responds to the DC current component of the flame signal,
thus ensuring that a short-circuit between ionization probe and ground cannot simulate
a flame signal (since in that case, AC current would flow).
Control sequence in the
event of fault
Lockout
Resetting the burner
control
Flame supervision with
ionization probe
