2.3 Vitocal 333-G BWT-NC, one heating circuit without mixer, DHW heating and natural
cooling
ID: 4605088_1304_07
Note
A system volume of at least 3 litres per kW of heat pump output is
required.
Application range
Detached house with underfloor heating system and cooling
demand.
Main components
■ Vitocal 333-G BWT-NC with integral DHW cylinder and
Vitotronic 200, type WO1C
■ Heating circuit distributor with heating circuit without mixer
■ Cooling with integral NC module
Requirements
The minimum flow rate of heat pump 1 is safeguarded by overflow
valve oW and the integral secondary pump. In these heating systems,
install an overflow valve at the heating circuit distributor of the under-
floor heating system. This safeguards a minimum volume of circulating
water, even in sealed heating circuits.
Note
Vitocal 333-G BWT-NC cannot be operated in conjunction with a heat-
ing water buffer cylinder.
Central heating by heat pump
Heat pump 1 and the integral primary pump start if the actual tem-
perature captured by the return temperature sensor in the secondary
circuit is lower than the temperature set at control unit 2 or for DHW
heating.
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 circuit. The integral secondary pump delivers the
heating water via a 3-way diverter valve either to the heating circuit or
to the integral DHW cylinder.
Opening and closing the valves of the underfloor heating distributor
regulates the flow rate within the heating circuit. Heat pump 1 and
the secondary pump are switched off once the actual return tempera-
ture at the return temperature sensor exceeds the temperature set at
the control unit.
DHW heating by heat pump
In the delivered condition, DHW heating by heat pump 1 is given
priority over the heating circuit 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.
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.
Natural cooling function
The Vitocal 333-G BWT-NC can cool the building. Control unit 2
enables the natural cooling function as soon as the outside tempera-
ture exceeds the cooling limit temperature that can be adjusted at
control unit 2. The integral 3-way diverter valves "Heating/cooling"
are switched to cooling, and the integral secondary pump transports
cooled water into the secondary circuit.
Contact humidistat iE monitors the dew point. Ensure that any instal-
led room thermostats are able to be opened manually or by servomo-
tors when using the cooling function.
Simultaneous DHW heating is not possible in this operating mode.
Required parameter settings
ID: 4605088_1304_07
Parameter Value Function
7000 2 With heating circuit A1/HC1, DHW cylinder (delivered condition)
7103 180 Min. flow temperature, cooling
7104 50 Influence room temperature hook-up cooling circuit
7111 4 Cooling curve slope
2003 1 Vitotrol 200A or 300B remote control activated for heating circuit A1/HC1
Vitocal 222-G/242-G/333-G/333-G NC/343-G (cont.)
System examples VIESMANN 15
5822 472 GB
2
