Viessmann VITOCAL 300-G Installation And Service Instructions Manual page 19

Function description for the system examples
Cooling operation
Cooling mode is possible either with one
of the available heating circuits, or with a
separate cooling circuit (e.g. chilled ceil-
ings or fan convectors).
Types and configuration
Subject to system version, natural cool-
ing, optionally with or without a mixer, or
active cooling are possible. For natural
cooling, the compressor is shut down
and heat exchange occurs directly with
the primary circuit. Active cooling uses
the heat pump as a refrigeration unit,
meaning a higher cooling capacity is
possible than with natural cooling.
Parameter "Cooling 7100" specifies the
type of cooling mode. Active cooling is
only possible outside a power-OFF
period, and must be enabled separately
by the system operator.
Enabling cooling mode
Operating instructions
Even if active cooling is selected and
enabled, the control unit will initially start
the natural cooling function. If the set
room temperature cannot be achieved
with this function, the compressor
starts.
A mixer can only be used with natural
cooling, and particularly in cooling mode
on underfloor heating circuits, it keeps
the flow temperature above the dew
point. To ensure the transfer of the high
cooling output in active cooling at all
times, no mixer is provided.
Preparing for installation
(cont.)
Operating status
Cooling mode in the heating circuits is
carried out in "Normal" and "Fixed val."
operating statuses. The separate cool-
ing circuit is additionally cooled in
"Reduced" and "Only DHW" operating
statuses. The latter enables continuous
cooling of a room, e.g. a warehouse dur-
ing the summer months.
The cooling output is subject to either
weather-compensated control according
to the heating or cooling curve, or room
temperature-dependent control.
Note
For cooling operation in the following
cases, a room temperature sensor must
be installed and enabled (parameter
"Remote control 2003" set to "1"):
■ Weather-compensated cooling mode
with room influence
■ Room temperature-dependent cooling
mode
■ "Active cooling"
A room temperature sensor must always
be installed for a separate cooling cir-
cuit.
Weather-compensated control
In weather-compensated cooling mode,
the set flow temperature is calculated
from the relevant set room temperature
and the current outside temperature
(long-term average) according to the
cooling curve. Its level ("Cooling curve
level 7110") and slope ("Cooling curve
slope 7111") are adjustable.
Room influence
19