Siemens LAL1.25 - Fault Conditions and Lockout Management; Lockout Indication and Fault Types; Lockout Reset Procedure

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Building Technologies Division CC1N7153en
21.09.2016
Control sequence under fault conditions and lockout indication
In case of any disturbance, the supply of fuel will immediately be interrupted.
Whenever a fault occurs, the sequence switch stops and with it the lockout indicator.
The symbol appearing above the reading mark indicates the type of fault:

No start  One of the contacts is not closed (also refer to «Preconditions for burner startup»)
 Extraneous light:
Lockout during or after completion of the control program
Examples:
– Nonextinguished flame
– Leaking fuel valves
– Faulty flame supervision circuit
=
Interruption of
startup sequence
 No «OPEN» signal at terminal 8 from the end switch «a»
 Terminals 6, 7 and 15 are live until fault has been corrected
P
Lockout Does not apply to LAL1:
 No air pressure indication at the beginning of the air pressure check
 Air pressure failure after the air pressure check

Lockout  Defect in the flame supervision circuit
>
Interruption of
startup sequence
 No positioning signal at terminal 8 from the auxiliary switch «m» for the low-fire
position
 Terminals 6, 7 and 15 are live until fault has been corrected
1
Lockout  No flame signal at the end of the safety time «TSA»
I
Lockout  Flame signal has been lost during operation
After the lockout reset, the burner control sequence switch first returns to the start
position and then initiates a burner restart.
If lockout occurs any other moment in time between start and preignition not indicated
by a symbol, the usual cause is a premature flame signal, that is, a faulty flame signal
caused, for instance, by extraneous light.
a-b Startup sequence
b-b´ Idle steps
(with no contact confirmation)
b (b´)-a Postpurge program
LAL1 LAL2, LAL3
 Burner control can immediately be reset after lockout:
– Do not press the lockout reset button for more than 10 seconds
 The sequence switch always travels to the start position first
– After resetting
– After rectification of a fault that led to shutdown
– After each power failure
During this period of time, power is only fed to terminals 7 and 9...11.
 Then, the burner control will program a new burner startup sequence

Note!
Do not press the lockout reset button for more than 10 seconds.
Lockout indicator