Drinking water heating process
Charging of the drinking water storage tank is started when the drinking water temperature in
the storage tank falls below the temperature value Drinking water heating ON or the value set
at a storage tank thermostat.
As a rule, the controller attempts to adapt the current flow temperature to the set Charging tem-
perature before the storage charging pump starts to operate. In such operating situations, the
flow temperature of the heating circuit may be raised by up to 10 K, however, up to the set limit
Max. flow temperature at the maximum.
When the heating circuit is deactivated, the controller does not attempt this; the storage charg-
ing pump starts up immediately, or when a return flow sensor is connected and FB 20 = ON is
activated with the option "SLP" selected, it first starts to operate when the return flow tempera-
ture reaches the temperature at the storage tank sensor SF1.
With the default setting FB 9 = OFF harsh priority, i.e. the heating circuit is deactivated while
the drinking water heating is active long-term charging can be interrupted after 20 minutes
for 10 minute periods by the heating operation. For this, set the function block FB 9 = OFF, and
select the option "20". The same applies to the setting FB 9 = ON with the option "US" selected
system with a circulation pump and changeover valve.
With the setting FB 9 = ON and the option "PU" selected parallel pump operation the heat-
ing circulation pump only continues to run when the increase in flow temperature in the heating
circuit is maximum 10 K Max. flow temperature at the maximum.
Should the capacity available for parallel operation be too low, causing the charging tempera-
ture to remain more than 5 K under the set value, the heating operation is interrupted for 10
minutes. The time span before the parallel operation is terminated can be set in FB 9.
The storage tank charging stops when the drinking water temperature in the storage tank
reaches the temperature value Drinking water heating OFF or the preset value at the storage
tank thermostat. This occurs when the flow temperature demand of the heating circuit is corre-
spondingly high because the storage charging pump has just been deactivated or in accord-
ance with the parameter setting End charging process when the flow temperature demand of
the heating circuit is lower. In any case, the storage charging pump is deactivated, at the latest,
after two transit periods of the control valve 2xTy have elapsed.
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