Siemens QAA73.210 - Page 26

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Siemens Room Unit for Boiler Control CE1U2283en
Building Technologies Description of room unit settings 2015-09-16
With pump heating circuits, the amount of heat supplied is controlled by switching
the pumps on and off. This is accomplished with 2-position control by means of the
room temperature's switching differential.
Legend
TRx Actual value of the room
temperature
TRw Room temperature setpoint
SDR Switching differential of room
temperature
ON Switch-on point
OFF Switch-off point
t Time
P Pump
Pump ON TRx = TRw
Pump OFF TRx = TRw + SDR
°C
ON
Legend
TRx Actual value of the room
temperature
TRw Room temperature setpoint
SDR Switching differential of room
temperature
P Pump (ON / OFF)
w Setpoint
Switch-on point
Switch-off point
The heating circuit pumps are controlled not directly by the QAA73.110, but by
boiler control. For this reason, this functionality is not ensured by the room unit
alone.
Room temperature setpoint for heating circuit 2. Active only if supported by BMU.
Flow temperature setpoint for heating circuit 2. Active only if supported by BMU.
OFF
ON
P
°C
TRx
TRw+SDR
2371D02
TRw
t
Note
(HC2SR)
(HC2SF)