Viessmann Vitocal 300-G BW, Installation And Service Instructions Manual

Page: 16 / 216

16
Active cooling (AC) function
The AC-Box enables, together with a
suitable brine/water heat pump active
cooling (AC operation) and natural cool-
ing (NC operation). The AC-Box is linked
directly to the brine and DHW circuit of
the heat pump and enables an external
circuit reversal to actively cool living
areas in summer. The following can, for
example, be connected to the AC-Box:
Fan convectors, cooling ceilings/sails
and underfloor cooling. During NC oper-
ation, the heat pump remains switched
off; only the primary pump is switched
on. This operation prevails until AC opera-
tion (active cooling with activated heat
pump) becomes necessary through an
excessive cooling load. In this case, the
resulting heating energy at the con-
denser is primarily used for DHW heating
or for heating swimming pool water, and
is secondarily stored, as far as possible,
in the ground for the following winter.
DHW heating
In the delivered condition, DHW heating
through heat pump takes priority over the
heating circuit. The control unit switches the DHW cir-
culation pump OFF during cylinder heat-
ing to prevent cylinder heating from
being impaired.
Instantaneous heating water heater
An instantaneous heating water heater
can be installed in the unit (accessory,
see separate installation instructions).
Subject to the available mains, the sys-
tem may be supplied with either 230 V~
or 400 V~. Protect the instantaneous heating water
heater via a separate connection.
The heat pump control unit regulates this
function.
Power-OFF
It is possible for the power supply utility
to shut down the compressor and instan-
taneous heating water heater together.
This is done through switching off the
main contactor (see page 90). This must not shut down the control unit
power supply.
Preparing for installation
Function description in connection with the…
(cont.)
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