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Siemens RDG100, RDG100T, RDG110, RDG140, RDG160 Basic Documentation CE1P3181en
Building Technologies Functions 14 Dec 2011
4.7.8 2-stage heating or cooling
On 2-stage applications, the thermostat controls 2 valves or compressors in
heating or cooling mode or changeover (automatic or manual).
“Cooling only" is factory-set (P01=1).
In heating mode, the 1st stage is activated if the acquired temperature is below the
setpoint.
The 2nd stage is activated if the acquired room temperature drops below “setpoint”
minus “setpoint differential”.
In cooling mode, the 1st stage is activated if the acquired temperature is above the
setpoint.
The 2nd stage is activated if the acquired room temperature rises above “setpoint”
plus “setpoint differential”.
The diagrams below show the control sequence for 2-position control.
Heating mode (P01=0) Cooling mode P01=1)
Y
TR [°C]
1
0
w
SDH
SDH
w
D
YHC2
YHC1
3181D15
Y
TR [°C]
SDCSDC
YHC1
YHC2
3181D16
w
w
D
1
0
Changeover (P01=2 or P01= 3)
T[°C] Room temperature
w Room temperature setpoint
YHC1 Control command “Stage 1"
YHC2 Control command “Stage 2”
SDH Switching differential “Heating” (P30)
SDC Switching differential “Cooling” (P31)
X
dz
Dead zone (P33)
Y
TR [°C]
SDH
SDH
SDC
SDC
Changeover
YHC2
YHC1
YHC2
3181D17
w
w
D
w
D
1
0
w
D
Setpoint differential (P34)
2-stage heating
or cooling
Heating mode
Cooling mode
ON/OFF control