Control Sequence Under Fault Conditions And Lockout Indication; Lockout Indicator - Siemens LAL1.25 Manual

Control sequence under fault conditions and lockout indication

Lockout indicator

12/20
Siemens Building Technologies
HVAC Products
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:
3 No start
=
Interruption of startup
sequence
P Lockout
Lockout
>
Interruption of startup
sequence
1 Lockout
I
Lockout
LAL1 LAL2..., LAL3..., LAL4...
·
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 LAL.... will program a new burner startup sequence
· 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
·
No OPEN signal at terminal 8 from the
changeover end switch «a»
·
Terminals 6, 7 and 15 are live until fault has
been corrected
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
·
Defect in the flame supervision circuit
· No positioning signal at terminal 8 from the aux-
iliary switch «m» for the low-fire position
·
Terminals 6, 7 and 15 are live until fault has
been corrected
·
No flame signal at the end of the safety time
·
Flame signal has been lost during operation
a-b Startup sequence
b-b´ Idle steps
(with no contact confirmation)
b (b´)-a Postpurge program
CC1N7153en
14.10.2002