Viessmann Vitocal 300-G Installation And Service Instructions Manual page 90

Installation sequence
Power supply
(cont.)
We recommend making the power
connection for accessories and
external components to the same
fuse, with at least the same phase
as the control unit.
Connection to the same fuse pro-
vides additional safety when the
power is switched off. However,
observe the power consumption of
the connected consumers for this
(control unit fuse protection max.
16 A).
If the compressor and/or the instan-
taneous heating water heater are
operated at a lower tariff (power-
OFF), provide an additional cable
for the switching contact "power-
OFF" (e.g. NYM 3x1.5 mm
the distribution board (meter box) to
the heat pump.
The power supply to the control unit
2
(3x 1.5 mm ) and the cable for the
power-OFF signal (for the control
unit) can be combined in a 5-core
cable. Observe the technical con-
nection requirements of the power
supply utility.
Combining the cables requires a
cable length of 2 m inside the appli-
ance plus wall clearance. Guide 2
individual cores for the power-OFF
signal through the rubber grommet
above the power terminals to
PCB 1.
90
Danger
The absence of component
earthing can transfer danger-
ous body currents, should an
electrical fault occur.
The appliance and the pipe-
work must be connected to the
earth bonding of the house in
question.
!
Please note
An incorrect phase sequence
can cause damage to the unit.
The power supply connection
to the compressor must have a
clockwise rotating field in the
phase sequence that is speci-
2
) from fied at the terminals.
In negotiations with your power sup-
ply utility, different feed tariffs for the
main power circuits may be offered.
The control unit/electronics feed
must be implemented without possi-
ble blocking from the power supply
utility; tariffs that are subject to possi-
ble shutdowns must not be applied to
these feeds.
The allocation of the power-OFF (for
compressor and/or instantaneous
heating water heater) is made via the
type of connection and by settings in
the control unit (see pages 92
and 83). Blocking of the main supply
is limited to max. 3 times 2 hours per
day (24 h) in Germany.