Emergency Off; In The Event Of Fire Or Electric Shock; Via The Safety Interlocks (Limits); Reset - Honeywell Krom Schroeder BCU 480 Manual

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6 . 7 Emergency off

6 . 7 .1 In the event of fire or electric shock

If there is a risk of fire, electric shock or similar, inputs
L1, N and 5 (safety interlocks) of the BCU should be
disconnected from the electrical power supply – this
should be reflected in the wiring on site.

6 . 7 .2 Via the safety interlocks (limits)

The safety interlock turns off the power to the input 5,
such as in the event of low air pressure or similar.Reset

6 .8 Reset

6 .8 .1 Parallel reset

Several automatic burner control units can be reset in
parallel using the external button. The BCU cannot be
reset by mains failure.

6 .8 .2 Permanent remote reset

Permanent remote reset gives rise to a malfunction. If a
remote reset signal is permanently applied to terminal
3, 52 flashes on the display to indicate a fault.
Reset with a pulse < 1 s.

6 .8 .3 Automatic remote reset (PLC)

In the case of automatic remote reset (PLC), the reset
pulse duration should not exceed 1 second. Check
compliance with standards.
If a fault is acknowledged by remote reset too often, er-
ror 10 (Too many remote resets) is displayed. The error
can only be acknowledged with the Reset/Information
BCU 480 · Edition 03.16l
button on the unit.
The burner malfunction must be remedied. The mal-
function cannot be remedied by changing the method
of activation.

6 .9 Burner start

A furnace start may only be initiated, if it has been ensured
using an appropriate procedure that there is no combus-
tible mixture in the combustion/processing chamber, in
the connected areas or in the exhaust gas system (heat
exchanger, dust collector). This can be achieved by pre-
purge, which occurs immediately before ignition or within
the period specified in the operating instructions.
In the case of multiple burner applications, pre-purge is
not necessary after a controlled burner shut-down.
Note the requirements of the Standards. For exceptions,
see Standards.

6 .10 Restart and start-up attempts

The precondition for a restart/start-up attempt is that
activation of the restart allows the burner to restart as
intended (in all operating phases). In this case, it must
be ensured that the program sequence started by the
BCU matches the application.
In accordance with EN 746-2, up to three start-ups are
permitted in specific cases if the safety of the instal-
lation is not impaired (note the requirements of the
Standards).
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