IFD 258 · Edition 10.09
26
7 Project planning information
7 .1 Cable selection
Use mains cable suitable for the type of operation and com-
plying with local regulations.
Signal and control line: max. 2.5 mm
2
.
Cable for burner earth/PE wire: 4 mm
2
.
Do not route IFD cables in the same cable duct as frequency
converter cables or other cables emitting strong fields.
Ionisation cable and ignition cable
Use unscreened high-voltage cable for both lines, see
[Accessories – p. 30].
Recommended cable length:
Ionisation cable – max. 75 m,
Ignition cable:
IFD 258: max. 5 m, recommended < 1 m (with TZI/TGI),
IFD 258..I: max. 1 m, recommended < 0.7 m.
The longer the ignition cable, the lower the ignition capacity.
Avoid external electrical interference.
Lay cables individually and not in a metal conduit, if
possible.
Lay the ignition cable and UV cable/ionisation cable as far
apart as possible.
Screw the ignition cable securely into the ignition transformer
TGI/TZI and feed it out of the unit on the shortest possible
route (no loops).
Only use radio interference suppressed electrode adapters
(with 1 k
Ω
resistor) for ignition electrodes, see [Accessories –
p. 30].
UV cable
The UV cable should be no longer than 100 m and should be
laid as far as possible from the ignition cable.
7 .2 Star electrodes
We recommend using 7.5 kV ignition transformers on burners
with star electrodes.
7 .3 Purge
In the case of multiple burner applications, burners with forced
air supply are used. The air for combustion and pre-purge is
supplied by a central fan controlled by a separate logic. This
logic determines the purging time and controls an external
relay that switches the air valve to purge.
The automatic burner control unit must not be activated during
purging. This is achieved by interrupting the safety interlock,
amongst other methods.
IFS 258
10
L1, N, PE
3
µC
BIO/
BIC
VR..R
11
8
9
13
14
4
5
GIK..B
VAS
SPS
N
Purge
