User Manual

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Siemens RXC20, RXC21, RXC22 – Room controllers CA2N3834en_12
Building Technologies 2015-12-23
• The dimensions and fuse protection for the supply cables depend on the total load
and on local regulations. The cables must be secured with cable restraints.
• If serial wiring is applied on the terminal block 19/21, the connection will be inter-
rupted if the block is removed from the controller (the jumpers 19-19 and 21-21 are
on the PCB, not in the block, see terminal diagrams on pages 10 … 12).
The volt-free relay outputs allow switching of loads up to AC 250 V, 5 A (4 A). The heat-
ing coil relay in the RXC22 switches resistive loads up to 1.8 kW.
The cable dimensions depend on the connected load and the local installation regula-
tions. The circuits must be externally fused (≤ 10 A) as there are no internal fuses.
The cables must be secured with cable restraints.
Parallel operation of the fans is not permitted.
The simultaneous load on outputs Y1 … Y4 must not exceed 9.5 VA.
Example: Y1 (heating) 2 thermic valve actuators, type STP73 5 W
Y2 (cooling) 2 thermic valve actuators, type STP73 5 W
Y3, Y4 (outside air) 3-position damper actuator 3.5 VA 3.5 VA
The maximum load is 8.5 VA for the heating sequence and 8.5 VA for the
cooling sequence. This is acceptable because the two sequences never
operate at the same time.
When using small loads (< 2VA), the voltage tolerance may be > + 20%
(see technical data, Triac outputs below)
Mounting instructions
The room controllers can be mounted in any orientation using the following fixing options:
Rail mounting
The housing base is designed for snap-
mounting on DIN rails, type EN50022-35 x
7.5 (can be released with a screwdriver).
Surface mounting
There are two drill holes for screw-mounting (see “Dimensions” for drill-
ing template). The housing base is fitted with raised supports.
Screws: Max. diameter 3.5 mm, min. length 38 mm
STOP
Note!
Tightening torque for fixing screws max. 1.5 Nm
AC 230 V supply cables
AC 230 V volt-free
relay outputs
STOP
Note!
AC 24 V triac outputs