Viessmann Vitolig
200 Technical Manual page 46

Application example 3
boiler, heating water buffer storage unit, Vitocell 333 and one or two heating circuits with mixer.
Priority cylinder heating in parallel operation Vitolig/heating water buffer storage unit
Notes
The water connection designs on the
following pages also apply to Vitolig 100.
Alternative functions and wiring
diagrams are described from page 64
onwards.
The temperatures stated in the
application example are standard values;
set alternative values according to the
relevant requirements.
The heating circuits and one DHW
cylinder are heated by Vitolig, one
Vitocell 333, one heating water buffer
storage unit and one oil− or gas−fired
boiler. The operation is automatically
changed over between Vitolig and the oil−
or gas−fired boiler. Both are either
connected to two different chimneys or to
one common chimney acc. to DIN 4759−1.
Combustion controller and control of the
Vitolig circulation pump
After Vitolig has been heated up, it is
operated at full load.
The Vitolig boiler circuit pump 2 is
switched on, when a boiler water
temperature of 60 ºC has been reached.
Either the heating circuit or the DHW
cylinder are heated up. The heat not
drawn off by consumers is transferred to
the heating water buffer storage unit.
The layer load operation begins, if 70 ºC
is exceeded for longer than 30 min. at
sensor qQ at the top of Vitocell 333.
Vitolig is operated at 50% output, and
Vitocell 333 is heated up to 80 ºC boiler
water temperature.
The layer load operation ceases, if the
temperature at the top of Vitocell 333 at
sensor qQ falls below 70 ºC. The boiler
output is enabled and the boiler water
temperature regulated to 70 ºC.
The Vitolig boiler circuit pump 2 is
switched off by the differential
temperature control if Vitocell 333 or the
heating water buffer storage unit is
loaded, and the boiler water temperature
is below that at sensor qW at the bottom
of the buffer (T + 5K).
PU
Return temperature raising facility
Vitolig requires a minimum return
temperature of 45 ºC. When the boiler
circuit pump 2 is switched on, the
mixing valve3 opens the path from the
heating return to Vitolig in line with the
rising return temperature, and
simultaneously closes the path from the
flow to the return (bypass).
Vitolig 200 (or Vitolig 100) with oil /gas fired boiler or wall−mounted gas−fired
Heating through Vitolig
If the Vitolig boiler water temperature lies
above 60 ºC, the heat generated by Vitolig
is transferred by the boiler circuit
pump 2 to Vitocell 333 or to the heating
water buffer storage unit.
The whole top section of Vitocell 333 is
heated, thereby also producing DHW.
Space heating with Vitolig and with solar
energy
When a temperature difference higher
than the differential temperature 2 preset
in Solartrol M wP is measured between
the temperature sensor wT and the
heating circuit return temperature
sensor wZ, the three way changeover
valve9 is switched to position "AB−A".
The heating return water is fed into the
boiler via the combination cylinder. If the
temperature of the pre−heated return
water is too low, the boiler re−heats the
water to the necessary flow temperature
level.
Domestic hot water heating without
solar energy
The top part of the combination cylinder
is heated by the boiler. The integrated
instantaneous water heater/standby
reservoir is heated by the surrounding
hot water of the buffer storage unit.
The DHW control thermostat with
connected DHW cylinder sensor qP of
the oil−/gas−fired boiler control unit
switches the circulation pump to heat
cylinder 4.
4 Vitolig 200
Domestic hot water heating with solar
energy
When a temperature difference higher
than the differential temperature 1 set in
Solartrol M wP is measured between the
collector temperature sensor wQ and the
cylinder temperature sensor wW, the
circulation pump of the solar heating
circuit wR is switched on and the
combination cylinder is heated up.
The temperature inside the combination
cylinder will, in this step, be limited by
the electronic temperature limiter in
Solartrol M wP.
If the preset temperature is exceeded, this
device switches off the circulation pump
of the solar heating circuit wR.
The electronic temperature limiter is
factory−set to 75 ºC and can be adjusted.
The entire combination cylinder will be
heated by the solar heating system if the
solar radiation is sufficient for heating the
domestic hot water.
The top part of the combination boiler
will only be re−heated by the boiler if the
temperature of the water falls below the
temperature set at the boiler control unit.
If the solar irradiation is insufficient, the
DHW will be pre−heated in the lower part
of Vitocell 333 by solar energy whilst the
top part is raised to the required
temperature by the boiler.
¨ Safety instructions
With temperatures higher than 60 ºC, the
domestic hot water temperature must be
limited to 60 ºC by installing a mixing
device, e. g. a thermostatic mixing valve
(DHW cylinder accessory). The mixing
device does not prevent the risk of
scalding at the drawing point.
The installation of a mixer tap is required.
Please note
To avoid re−circulation, it is advisable to
install a heat insulating loop or an
additional check valve into the flow of the
solar heating circuit.
47