Function
WE
Configuration
Circulation pump operation
during storage tank charging
0
CO4 -> F11
6.7
Priority operation
In many district heating systems with primary DHW heating, the alloted amount of water is
only intended to supply the heating system. As a result, the capacity required for DHW heat-
ing needs to be taken from the heating system when great heating loads occur; and this, until
DHW heating has been concluded.
Nevertheless, heating operation is not to be interrupted simply. Only the amount of energy
required for DHW heating is to be deducted. This can be achieved by using the priority func-
tions
Reverse control
and
Set-back operation
.
6.7.1 Reverse control
In all systems with DHW heating and at least one heating circuit with control valve, DHW
heating can be given priority by applying reverse control. With the setting CO4 -> F08 - 1,
the charging temperature can be monitored.
In systems without the sensor VFx in the DHW circuit (e.g. Anl 4.5, Anl 11.0), the tempera-
ture directly at the storage sensor SF1 is monitored. If system deviations occur after the time
for
Activate priority in case of deviation has elapsed, the set point of the heating circuit with
the control valve (the set point of heating circuit RK2 in systems Anl 10.1 to 10.3) is gradu-
ally reduced each minute until the flow temperature set point has reached 5 °C at the mini-
mum. How strongly the controller responds is determined by the
Correction factor.
Functions
WE
Configuration
Priority through reverse control
0
2 min
1.0
CO4 -> F08 - 1
Activate priority in case of deviation / 2 to 10 min
Correction factor / 0.1 to 10.0
Priority through set-back operation 0
CO4 -> F09 - 0
6.7.2 Set-back operation
In all systems with DHW heating and at least one heating circuit with control valve, DHW
heating can be given priority by applying set-back operation. With the setting
CO4 -> F08 - 1, the charging temperature can be monitored. In systems without the sen-
sor VFx in the DHW circuit (e.g. Anl 4.5, Anl 11.0), the temperature directly at the storage
sensor SF1 is monitored. If system deviations occur after the time for
Activate priority in case
68
EB 5576 EN
Functions of the DHW circuit
