APPENDIX - TECHNICAL CHARACTERISTICS
29
LANDIS OIL BURNERS AUTOMATIC CONTROLLER LOA44
Operation
Burners without fuel pre-heater
Start-up, thermostat and pressure switches R, burner motor G and
ignition transformer Z are all controlled at the same time.
After about 25 seconds the solenoid is energised (in this period the
flame amplifier is at maximum sensitivity). The command to the first
solenoid BV1 marks the start of the safety time during which, either
there is no flame in the burner and the controller locks it out, or after 5
seconds the stage 2 solenoid BV2 is energised and this ends the bur-
ner start-up programme.
Burners with fuel pre-heater
(Operational all-clear from contact OW which short circuits terminals
3 and 8). The burner start-up programme is exactly the same as
above except that it is initiated by the closing of the OW contact of the
preheater OH.
When the flame lights the flame relay contact (fr2) is short circuited
and should the contact OW open that does not cause a lockout but a
repetition of the cycle.
Commands in the event of operational interference
Premature ignition / Flame present during pre-purge: Lockout and
termination of pre-purge
Defective components in controller or electronic programmer:
Lockout
No flame signal at the end of safety time: Lockout
No flame during post-ignition: Lockout
No flame during normal operation: Repetition of start-up pro-
gramme
Power cut during start-up programme or operation: Automatic
repetition of programme when power restored.
Lack of sufficient power (~160V): Solenoid BV1 de-energised, sole-
noid BV2 de-energised when flame goes out
Lockout which occurs within less than 1 second, cuts off power to ter-
minals 3-8 and 12; terminal 10 still remains live in order to activate the
optical lockout indicator. The controller can be reset 2 seconds after a
lockout.
Important: when external wiring is replaced ensure that it is switched
on at the same phase of terminal 2 (so that terminal 9 is connected up
to neutral).
Electrical connections and programmer's layout
A’
burner start-up
B
Flame signal with oil pre-heater present
C
End of programme-start of normal operation
A
burner start-up
C-D
normal operation without oil pre- heater
D
normal stop
Programme or command cycle
tw
fuel pre-heating time acc. to system
tl
pre-purge time, ~25secs.
t3
pre-ignition time, ~25secs.
t2
safety time max.5 secs.
t3n
post-ignition time, ~2 secs.
t4
interval between BV1 and BV2 commands, ~5 secs* - lockout
from absence of flame, <1 sec.
* In relation to the moment when the flame occurs.
Key to internal diagram
AL
Remote optical lockout indicator
AR
Main relay with contacts ar...
BV..
Fuel solenoid
BR
Lockout relay with contacts br..
EK
Reset button
FR
Flame relay with contacts fr...
FS
Flame present signal
G
Burner motor
HR
Auxiliary relay with contacts hr..
L
Lockout LED incorporated in the reset button
OH
Fuel pre-heater
OW
All-clear contact for pre-heater
QRB Photo resistor (flame detector)
R
Normal thermostat or pressure switch
V
Flame signal amplifier
W
Safety thermostat or pressure switch
Z
Safety transformer
