Furnace Control; Note On Ec Type-Examination; Mains Switch; Changing Parameters - Honeywell Krom Schroder PFU 780 Technical Information

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6 .12 Furnace control

Switch on the system to start up the furnace, then
release the burner start via the safety interlocks and
afterwards start the burner control so that the burner
control unit may monitor the burners as intended. To
shut down the furnace, first disconnect the burner
control unit from the temperature control (burner ON
signal), then disconnect the safety interlocks and finally
switch off the system.

6 .13 Note on EC type-examination

Since EN 298 (1993) does not describe all functions of
the PFU, the operator is responsible for ensuring that all
parameters and functions are matched to the respec-
tive application.

6 .14 Mains switch

The mains switch in the unit isolates the PFU on two
poles from the mains. It does not meet the require-
ments of EN 50156-1:2004 (5.2.2 Switch disconnec-
tors) set out in chapter 5 for a device to disconnect the
power supply. Although the mains switch cannot be
used for disconnecting from the electrical power supply
in accordance with EN 50156, it does allow the burner
to be isolated functionally from the central control sys-
tem. This function is required for manual operation and,
in the case of PROFIBUS units, to switch off the unit
without causing BUS errors. Disconnection for electri-
cal maintenance work is to be implemented with an ex-
PFU 780 · Edition 02.12l
ternal switch per unit or group only, in accordance with
Standard "EN 50156".

6 .15 Changing parameters

In certain cases, it may be necessary to change the de-
fault settings. Using a separate software package and
a PC opto-adapter, it is possible to modify certain pa-
rameters on the PFU, such as the switch-off threshold
of the flame amplifier, the behaviour in the event of a
flame failure or if the pilot burner is to burn permanently
in the case of pilot and main burner monitoring.
The software package with PC opto-adapter, as well as
"Changed parameters" stickers, are available as acces-
sories – see section entitled page 56 (Accessories) .
The unit parameters set at the factory are specified in
the delivery note.
Document changed parameters in BCSoft using the
protocol function and enclose the protocol with the
plant documentation.
If a replacement is ordered for a PFU with changed pa-
rameters, refer to the protocol for details.
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