Heating Through Heating Water Buffer Storage Unit - Viessmann Vitolig
200 Technical Manual

4 Vitolig 200
H Heating through heating water buffer
storage unit
If the Vitolig boiler water temperature
falls, more heat is drawn from the heating
water buffer storage unit, the more the
mixing valve 4 of the return
temperature raising facility opens the
path from the boiler flow to the boiler
return (bypass). The boiler circuit
pump 3 is switched off and the heat is
only drawn from the heating water buffer
storage unit, when the boiler water
temperature falls below 55 °C.
The heating water buffer storage unit
provides the heating, until the actual
temperature falls below the temperature
set at thermostat qW (manually matched
to the heating system return temperature,
e.g. 40 ºC in spring and autumn, and, for
example, 60 ºC when there is a high heat
demand). Thermostat qW on the heating
water buffer storage unit determines the
necessary heating flow temperature. The
three−way changeover valve qP changes
to connect the oil− or gas−fired boiler with
the distributor, the burner of the oil− or
gas−fired boiler starts and heating will be
provided by that same boiler, if the
temperature inside the heating water
buffer storage unit falls below the value
set at thermostat qW.
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