Specifications

4
4. It is suggested to use a shielded cable
for all installations.
5. The shielding of the cable has to be
connected with earth potential, i.e.
boiler covering, connecting terminals -
for earth potential etc. Multiple
grounding is not permitted (humming
loop).
In star shaped networks it is not
permitted to ground cables on both
sides. They should be grounded in the
center.
6. The outside sensor may not be
installed close to transmitting or
receiving equipment (on garage walls
close to receivers for radio-controlled
garage door openers, amateur radio
antennas, radio controlled alert
systems or close to large scale radio
transmission equipment).
Recommended cable cross-sections
and maximum permitted cable lengths:
A – Sensor lines
For all low voltage cables such as
sensors, external selectors, bus and
analogue in- and outputs, heat requiring
by means of external contact, modem
connection cables, etc.: 0.0008 in (0.5 mm )
2
Maximum permitted cable length: 164 ft
(50 m).
Longer connecting cables should be
avoided in order to reduce the risk of
electrical interference.
B – Data bus lines
Recommended cable:
J-Y(St)Y 2 x 0.0009 in (0.6 mm )
2
Maximum permitted cable length: 164 ft
(50m)
Longer connecting cables should be
avoided in order to reduce the risk of
electrical interference.
Fig. 5: Grounding in star shaped networks
Screen
2-wire
data bus line
Distribution
terminal
Distribution box
Do not ground here!
Fig. 4: Screen grounded in centre
Boiler control in
boiler control unit
Connection,
depending on version,
directly or via suitable
interface
2
2
(18 AWG)
(18 AWG)