Viessmann FB2B Installation And Service Instructions Manual page 18

Installation sequence
Electrical connections
Never interchange cores
"L1" and "N".
■ Install an isolator in the power
supply line that simultaneously
isolates all non-earthed conduc-
tors from the mains with at least
3 mm contact separation.
We additionally recommend
installing an AC/DC-sensitive
RCD (RCD class B
DC (fault) currents that can occur
with energy efficient equipment.
Remove the existing cable grom-
met when using larger cross-sec-
tions (up to 714 mm). Secure the
cable with cable grommet F (see
page 21) integrated into the cas-
ing base.
■ Max. fuse rating 16 A.
gD External safety solenoid valve
(LPG) C
Do not remove jumper between "1"
and "L" when making this connec-
tion.
lH Power supply of accessories
Where the boiler is installed in a wet
area, the connection of accessories
to the power supply must not be car-
ried out at the control unit. If the
boiler is installed outside wet areas,
the power supply for accessories
can be connected directly to the
control unit (230 V/50 Hz). The con-
nection is switched by the system
ON/OFF switch.
Note
If the total system current exceeds
6 A, connect one or more extensions
via a mains isolator directly to the
mains supply; see page 19.
18
(cont.)
Low voltage plug X3
! Outside temperature sensor
Installation:
■ North or north-western wall, 2 to
2.5 m above ground level; in multi-
storey buildings, in the upper half
of the second floor
■ Not above windows, doors or ven-
tilation outlets
■ Not immediately below balconies
) for
or gutters
■ Never render over
■ Cable length max. 35 m with a
cross-section of 1.5 mm
? Flow temperature sensor for low
loss header (accessories)
% Cylinder temperature sensor (fitted
and connected)
aVG KM BUS subscriber (accessory)
■ Vitotrol 200A or 300A remote
control
■ Vitocom 100
■ Extension kit for one heating cir-
cuit with mixer
■ Extension AM1 or EA1
■ Open Therm extension
2