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Control sequence in the event of fault
Siemens Building Technologies
HVAC Products
In case of any disturbance, the supply of fuel is immediately interrupted. At the same
time, the sequence switch stops and thus the lockout indicator also.
The symbol appearing above the reading mark indicates the kind of fault:
No start, because one of the contacts is not closed (also refer to «Prerequisites for
burner startup») or lockout during or after completion of the control sequence due
to extraneous light (e.g. flame not extinguished, leaking fuel valves, faulty flame
supervision circuit, or similar).
Abortion of startup sequence, because end switch «a» has not fed the OPEN sig-
nal to terminal 8. Terminals 6, 7 and 14 and, in case LOK16... is used, terminal 15,
also remain live until the fault is corrected.
P
Lockout, because the air pressure signal has not been received at the start of the
air pressure check.
Lockout due to a fault in the flame supervision circuit.
Abortion of startup sequence, because auxiliary switch «m» has not delivered the
positioning signal for the low-fire position to terminal 8. Terminals 6, 7 and 14 and,
in case LOK16... is used, terminal 15, also remain live until the fault is corrected.
1
Lockout, because no flame signal has been received on completion of the (first)
safety time.
2
Only with LGK16...:
Lockout, because no flame signal has been received on completion of the second
safety time (flame signal of the main flame with interrupted pilot burners).
I
Lockout, because the flame signal has been lost during burner operation or air
pressure failure has occurred.
Only with LOK16...:
If wire link «B» was cut off and the flame is lost during burner operation, the burner
control programs a repetition of the startup sequence with the full program.
11/20
CC1N7785en
15.10.2003
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