H Dual Mode Dhw Heating And Central Heating Backup By Heating Water Calorifier, With Vitosolic 200 - Viessmann Vitosol
100 Technical Manual

4.2 System design 2
Dual mode DHW heating and central heating backup by heating water calorifier, with
Vitosolic 200
DHW heating without solar energy
The upper indirect coil of the DHW
cylinder is heated by a boiler. The
cylinder thermostat with cylinder
temperature sensor 6 of the boiler
control unit switches the cylinder loading
pump 7.
DHW with solar energy
Solar circuit pump 4 is switched ON, if a
temperature differential higher than
start−up temperature differential DT
measured between collector temperature
sensor 2 and cylinder temperature
sensor 3.
Pump 4 is switched OFF when:
H the actual temperature falls below
shutdown temperature differential DT
H the electronic temperature limit (safety
shutdown at 90 ºC) set at the control
unit or that set at the high limit safety
cut−out (if required) is exceeded.
The additional function requirements (see
page 60) are met by circulation pump 8.
Central heating without solar energy
Diverter valve qW remains at zero volts
(setting AB−B), if the differential
temperature between calorifier
temperature sensor qP and central
heating return temperature sensor 9
falls below shutdown temperature
differential DT6
. No flow through the
off
heating water calorifier takes place.
The boiler provides heat to the heating
circuit according to the heating curve set
at the boiler control unit.
VITOSOL
Central heating with solar energy
When the DHW cylinder cannot be
heated, and the temperature differential
between collector temperature sensor 2
is
on
and calorifier temperature sensor qQ is
greater than start−up differential DT2
circulation pump qE for heating heat
exchanger qT will be started, and
switched OFF when the temperature falls
below shutdown temperature DT2
off
when maximum temperature T
has been reached.
Calorifier loading pump qR is switched
ON, if a temperature differential higher
than the start−up temperature differential
DT5
is measured between temperature
on
sensor qZ (heat exchanger) and calorifier
temperature sensor qQ.
Pump qR is switched OFF , if the actual
temperature falls below shutdown
temperature differential DT5
circulation pump qE is switched OFF .
The temperature in the calorifier is limited
by the electronic temperature limiter
(safety shutdown at 90 ºC) or by the high
limit safety cut−out (if required). It will
switch calorifier loading pump qE OFF , if
the set temperature is exceeded.
4.2 System design 2
Circulation pump qE is switched OFF for
approx. 2 minutes, roughly every 15
minutes (values t−st and t−circ adjustable),
to check whether the temperature at the
collector temperature sensor is high
enough to change over to DHW cylinder
, loading. The DHW cylinder continues to
on
be loaded if, during that time, DT
exceeded.
Diverter valve qW is set to AB−A, if the
or
off
differential temperature between
cyl2max
calorifier temperature sensor qP and
heating return temperature sensor 9
exceeds start−up temperature differential
DT6
; the heating return water will be
on
routed to the boiler via the calorifier. If the
temperature of the pre−heated return
water is insufficient, the boiler re−heats
the water to the necessary flow
temperature level.
or if If the actual temperature falls below
off
shutdown temperature differential DT6
the diverter valve will be set to AB−B.
is
on
off,
65