Viessmann VITOTRONIC 200 Service Instructions Manual page 27

Heating circuits/cooling circuit
Systems with large water volumes
Systems with large water volumes (e.g.
underfloor heating systems) can operate
without a heating water buffer cylinder.
In these heating systems, install an over-
flow valve at the heating circuit distribu-
tor of the underfloor heating system that
is furthest away from the heat pump.
This safeguards the minimum flow rate,
even in sealed heating circuits.
Central heating/cooling via a heating/cooling circuit
The heat pump control unit can control
one heating circuit without mixer and a
maximum of two heating circuits with
mixer.
In this respect one heating circuit can
also be used for cooling (as a heating/
cooling circuit) (Parameter "Cooling
7101").
Note
If a separate cooling circuit is connected,
a heating circuit cannot be used for cool-
ing.
Subject to the heat pump type, the fol-
lowing configurations are possible for
heating circuits with mixer:
■ Up to 1 heating circuit with mixer M2:
Control of the mixer motor via KM BUS
(extension kit for heating circuit with
mixer required).
■ Up to 2 heating circuits with mixer:
– Direct control of the mixer motor for
heating circuit with mixer M2 with
signal 230 V~.
– Control of the mixer motor for heat-
ing circuit with mixer M3 via KM BUS
(extension kit for heating circuit with
mixer required).
(cont.)
As a heat demand, the heat pump
receives the maximum value of the
demands from all heating circuits. The
flow temperature of heating circuit with-
out mixer may consequently become
higher than necessary.
Subject to the outside temperature, the
heat pump control unit switches between
central heating/cooling and frost protec-
tion mode.
For central heating/coding, the required
start and stop limits can be set as differ-
entials for the set room temperature:
■ Heating limit:
Set room temperature – "Tempera-
ture differential for calculating the
heating limit 7003"
■ Cooling limit:
Set room temperature + "Tempera-
ture differential for calculating the
cooling limit 7004"
Function description
27