Samson 5100, 5179 operating instructions 6.3Priority operation, Reverse control, Appendix

Appendix

Parameters	WE	Parameter level / Range of values
DHW demand ON	40 °C	PA4 / 20 to 90 °C
Hysteresis	5 °C	PA4 / 0 to 30 °C
Charging temperature	55 °C	PA4 / 20 to 90 °C
Storage tank charging pump	50 °C	PA4 / 20 to 90 °C
deactivation limit

6.3Priority operation

In many district heating systems with primary DHW heating, the allotted amount of water is only intended to supply the heating system. As a result, the capacity required for DHW heating 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 simply interrupted. Only the amount of energy re- quired for DHW heating is to be deducted. This can be achieved by using the priority functions Reverse control and Set-back operation.

6.3.1 Reverse control

In all systems with DHW heating and at least one heating circuit with a control valve, the DHW heating can be given priority by applying a reverse control. With the setting Co4 -> Fb06 = ON, the charging temperature can be monitored. If the temperature also falls below the charg- ing temperature after the time period set in function block Fb07 has elapsed, the heating circuit is closed and the set point remains the same.

Which circuit is closed depends on how the system (Anl) is configured:

￿Anl 2:	Heating circuit with the highest flow set point
￿Anl 4:	Heating circuit
￿Anl 5:	Heating circuit 1;
	Switching off the pump heating circuit with Co4 -> Fb05 possible.
￿Anl 7:	Pre-control circuit of heating
￿Anl 8:	Pre-control circuit of heating
￿Anl 9:	Heating circuit 1
￿Anl 10:	Both heating circuits

Functions	WE	Configuration
Reverse control	ON	Co4 -> Fb06 = ON
Time until reverse control	ON	Co4 -> Fb07*

* Co4 -> Fb07 = ON: 2 minutes Co4 -> Fb07 = OFF: 10 minutes

56EB 5179 EN