Data Sheet for Product

5/12
Siemens Building Technologies Heat-pump controller for wall mounting ACR12.481 CE1N3577en
HVAC Products 27.05.2004
With 10 % control of the heating or cooling valve, the fan switches to speed I, with 80 %
to speed II and with 100 % to speed III. The switching hysteresis of the fan speeds are
shown in the following diagram.
Q1
Q2
Q3
010
50
80
100
0105080100
3575D04
Q
K
[%]
Q
H
[%]
W
H
W
K
X
p
X
p
X
dz
Ventilation in neutral zone OFF. (parameter P08 = 1).
If a return air sensor is used (B2, M) then the fan is switched ON for 2 min every
30 min. as long as the controller remains in the dead (neutral) zone.
Note that with an external electric heater the return air sensor cannot be used since the
fan is not periodically switched when the controller is in heating mode.
W
H
W
K
X
p
X
p
X
dz
Q1
Q2
Q3
50 80 1005080100
3575D05
Q
K
[%]
Q
H
[%]
Ventilation ON in neutral zone of comfort mode
Ventilation OFF in neutral zone of economy or frost protection.
(Parameter P08 = 0).
Legend to the drawings above:
Q1 Fan speed 1 W
H
Heating set-point
Q2 Fan speed 2 W
K
Cooling set-point
Q3 Fan speed 3 X
p
P-band
Q
H
Heating demand X
dz
Neutral zone
Q
K
Cooling demand
There is a speed dwell time defined of 1 minute (minimum duration of one state). This
dwell time is used in automatic operation and cannot be changed. It prevents the fan-
speed from changing too often.
Alarm input
The input B2, M for the external sensor is also used as alarm input. If the external sen-
sor and the alarm input are both used, then they have to be connected serially. The
rules for the input at B2 and M are the following:
• If the resistance between B2 and M is > 10K Ohm or open circuited (< 0°C) then
this means alarm.
• If the resistance is < 1.5K Ohm or short circuited (> 40.0°C) this means no sensor
is connected and the internal sensor is used instead.
• If the resistance is according to a temperature of > 0°C and < 40°C then the exter-
nal sensor is used.