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Parameters
4 .8 Manual operation
For convenient setting of the burner or analysing faults.
The parameter display is not available in Manual mode.
Manual mode can be accessed only if the unit was not in
Fault state before switching off. The following times/functions
are not active in Manual mode: start-up attempts, restart,
minimum combustion time and cycle lock.
If the Reset/Information button is pressed for 2 s during switch-
on, the PFU reverts to Manual mode. Two dots blink on the
display.
In this operating mode, the burner control unit operates inde-
pendently of the status of the inputs (apart from the pre-purge
input and the safety interlocks. These are of higher priority and
will be processed first).
Each time after the button is pressed again, the PFU moves
to the next section of the program sequence and stops there.
After approx. 3 s, the flame signal will be displayed instead of
the program parameter. Briefly pressing the Reset/Informa-
tion button (< 1 s) displays the relevant Manual mode step. If
there is flame simulation during the start-up, the flame signal
is displayed immediately.
On units with air valve control, the air valve can be opened
and closed repeatedly by pressing the button during operation.
Manual mode can be terminated by switching off the PFU
(On/Off button).
PFU 780 · Edition 02.12
4 .8 .1 Manual mode limited to 5 minutes
Parameter 34:
Parameter 34 determines when Manual mode is terminated.
Parameter 34 = 0:
Manual mode is not limited in time. If this function has been
selected, operation of the furnace may be continued manually
in the event of failure of the central control system.
Parameter 34 = 1:
Manual mode ends automatically five minutes after the last
time the button was pressed. The PFU then moves abruptly
back to start-up position/standby.
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