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Siemens Building Technologies Heat-pump controller for wall mounting ACR12.481 CE1N3577en
HVAC Products 27.05.2004
Q
K
X
p
X
p
Q
H
W
K
3575D03
YCYHE
Y [%]
80
50
X
dz
50%
W
H
100
Q
H
Heating demand W
H
Heating set-point
Q
K
Cooling demand W
K
Cooling set-point
X
p
P-band
Y Positioning variable
YHE Electric heater output
YC Compressor output
YR Reversing valve output
Electric heater
If no reversing valve is available then the output of the controller can be used for
switching an external relay for an electric heater.
The controlling of the heater depends on the control deviation (the output is pulse dura-
tion modulated).
The cycle time is 240 s. For safety reasons, max. 50 % of heating output is possible at
manual fan speed I (relay 120 s “on” and 120 s “off”), at speed II max. 80 % and at
speed III max. 100 %.
Note that if the electric heater is inside the fan coil and is active then the fan will not
switch off immediately when for example the mode is changed from comfort to econ-
omy. The fan continues to run until the protection time of the heater has passed
(1...4 min, depending on the situation).
Changeover between heating and cooling operation
A changeover of the heat pump system between heating and cooling is only possible if
a reversing valve is available (defined by parameter P09). Parameter P10 defines in
this case whether the change-over happens automatically when the corresponding set-
point is reached or whether the controller must be switched manually from one state to
the other. There is a special key available on the controller for switching manually be-
tween heating and cooling (
)
Fan operation
In automatic mode (fan speed selector switch on the controller set to “Auto“) and the
controller in neutral zone, the fan can be operated in two different modes (defined by
P08). In one mode the ventilation remains constantly at speed 1, in the other mode it is
switched off in the neutral zone.
If the fan starts from standstill to stage 1, it starts with stage 3 for 1 second in order to
start reliable.
Cooling with com-
pressor, heating with
electric heater