Viessmann Vitocal 222-G User Manual page 20

Vitocal 222-G/242-G/333-G/333-G NC/343-G
2.5 Vitocal 222/242-G, one heating circuit without mixer, one heating circuit with mixer,
DHW heating (for Vitocal 242-G also solar) and heating water buffer cylinder
ID: 4605091_1304_05
Note
DHW heating with solar backup is only possible with the
Vitocal 242-G.
Application range
Detached house with up to two heating circuits with different utilisation
patterns (different heating circuit design layouts).
Main components
■ Vitocal 222/242-G with integral DHW cylinder and Vitotronic 200,
type WO1C
■ Heating circuit distributor with one heating circuit without mixer and
one heating circuit with mixer (controlled via KM BUS)
■ Heating water buffer cylinder
■ Solar thermal system (option, only with the Vitocal 242-G)
Requirements
The minimum flow rate of heat pump 1 is safeguarded via heating
water buffer cylinder zP and the integral secondary pump. It is possible
to use differential pressure-dependent heating circuit pumps uZ and
oZ.
Central heating by heat pump
Heat pump 1 and the integral primary pump start when the actual
temperature captured by cylinder temperature sensor zQ of heating
water buffer cylinder zP falls below the set temperature selected at
control unit 2.
Heat pump 1 supplies the heating circuit with heat. Control unit 2
of heat pump 1 regulates the heating water flow temperature and
thereby the heating circuits. The integral secondary pump delivers the
heating water via a 3-way diverter valve either to heating water buffer
cylinder zP or to the integral DHW cylinder.
Required parameter settings
ID: 4605091_1304_05
Parameter
7000
7A00
C002
System examples
Value Function
6 With heating circuit A1/HC1, M2/HC2, DHW cylinder
3 Solar control module, type SM1
2 Variable speed solar circuit pump with PWM activation
(cont.)
Heating circuit pumps uZ and oZ deliver the required water volume to
the heating circuits. The heating circuit flow rate is regulated by open-
ing and closing the thermostatic radiator valves or the underfloor dis-
tributor valves and/or through an external heating circuit control unit.
Heat pump 1 and the integral secondary pump are switched off once
the actual return temperature at the return temperature sensor
exceeds the temperature set at the control unit.
To balance the difference in energy between the primary and secon-
dary circuits, operate heating water buffer cylinder zP in parallel to the
heating circuits. Any heat not absorbed by the heating circuits is stored
in heating water buffer cylinder zP. In addition, heat pump 1 achieves
long runtimes.
During the power-OFF period, the heating circuits will be supplied with
heat from heating water buffer cylinder zP.
DHW heating by heat pump
In the delivered condition, DHW heating by heat pump 1 is given
priority over the heating circuits and takes precedence at night.
The heat demand is issued via the integral cylinder temperature sensor
and the control unit, which controls the integral secondary pump in
conjunction with the integral 3-way diverter valve and, in the case of
the Vitocal 242, the cylinder loading pump.
The control unit raises the flow temperature to the value required for
DHW heating.
The control unit switches the heating flow to the heating circuit via 3-
way diverter valve "Heating/DHW" if the actual temperature at the cyl-
inder temperature sensor exceeds the value set at the control unit.
The flow temperature can be raised > 60 °C via integral instantaneous
heating water heater 4.
DHW heating with solar backup (only for Vitocal 242-G)
The DHW cylinder will be heated by the solar collector if the temper-
ature differential between collector temperature sensor rR and the
integral lower cylinder temperature sensor exceeds the temperature
differential set at the control unit. For this, the heat pump control unit
controls solar circuit pump rE which is integrated into Solar-Divicon
rW.
The control unit stops solar circuit pump rE again if the temperature
falls below the temperature differential.
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VIESMANN
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