Data Sheet for Product
6/12
Siemens Building Technologies Heat-pump controller for wall mounting ACR12.481 CE1N3577en
HVAC Products 27.05.2004
If an alarm occurs then all outputs are switched off and the text “Err” is shown in the
display. The operating mode is switched to standby and nothing can be done until the
alarm disappears. When it disappears, the p
ointer to the standby sign ( ) appears in the
display in addition to “Err”. By pressing the Standby / AUTO /Fan-speed key, the alarm can
now be reset and the operating mode is changed back to AUTO and the text “Err” disap-
pears.
Note that with an electrical heater active the fan is only switched off when the protection
time of the heater is over (1...4min). The heating symbol is blinking during the time the
fan cannot be switched off because of the protection time.
Window Contact Input
The window contact input (DU1, GND) is used to switch the operating mode from nor-
mal mode (defined by P01) to reduced mode (defined by P02). The idle position of the
contact is defined by P03.
The window contact input is separated from 230V and is SELV (Secure Electric Low
Voltage). No additional power supply is needed for detecting the position of the external
contact (the current necessary is delivered by the controller).
Several contacts can be wired serially and up to 30 controllers can be connected to
these contacts. Make sure that GND is connected with GND and DU1 with DU1 of
the different controllers. The maximum cable length should not exceed 250m.
Since the currents of the individual inputs sum up, the diameter of the wires must care-
fully be chosen. If the diameter of the wires in the cable is below 1 mm
2
, then the follow-
ing graph shows the relationship between cable length, number of units connected in
parallel and the wire diameter.
0
5
10
15
20
25
30
0 50 100 150 200 250
Maximum cable length
Number of units
0.14 mm
2
0.25 mm
2
0.36 mm
2
0.08 mm
2
0.50 mm
2
0.75 mm
2
16 controllers are switched in parallel and the wire diameter is 0.25 mm
2
, then the
maximum cable length must not exceed 110 m. However with wire diameters of 0.75
mm
2
250 m are possible with up to 21 controllers.
Settings
Security
Wiring Controllers
Example of wiring