Nu-Way MOL 3400-410, Installation & Maintenance Manual

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Control Program under Fault Conditions and Lockout Indication
In the event of fault conditions the sequence switch stops and simultaneously the lockout indicator. The
symbol appearing above the reading mark indicates the kind of fault encountered.
When lockout occurs, the control can be reset immediately. After the resetting (and also after the
correction of a fault which resulted in a controlled shutdown, or after each mains failure) the sequence
switch always runs through to the start position, whereby
only terminals 7, 9, 10 and 11 receive voltage in
accordance with the control program. It is only then that the control unit programs a fresh burner start-up.
Note: Do not press the lockout reset button (or remote reset switch) for more than 10 seconds.
MOL 3400-4100 Issue 2 10/08
Page 28
Symbol Fault
No start , because, e.g. the CLOSE signal has not been supplied to control box
terminal 8 by the servo motor limit or auxiliary switch, or a contact has not been
closed between control box terminals 12 and 4 or 4 and 5.
▲
Shut down of start-up sequence , because the OPEN signal has not been supplied
to control box terminal 8 by the servo motor limit switch. Terminals 6, 7 and 15
remain under voltage until the fault is corrected.
■
Lockout due to a fault in the flame supervision circuit.
▼
Shut down of start-up sequence , because the signal for the low flame position has
not been supplied to control box terminal 8 by the servo motor auxiliary switch.
Terminals 6, 7 and 15 remain under voltage until the fault is corrected.
1
Lockout , because no flame signal has been received on completion of the safety
time.
I
Lockout , because the flame signal has been lost during burner operation or an air
pressure failure has occurred.
Lockout on completion or after completion of the control program sequence
due to extraneous light (e.g. flame not extinguished, leaking fuel valves) or due to a
faulty flame signal (e.g. fault in the flame supervision circuit or similar).
a - b Start-up sequence
b - b’ Idle steps up to the self shutdown of
the sequence switch
b(b’) - a Post purge sequence