Stulz Tel-Air-2 Series, Operating Instructions Manual

Page: 48 / 72

E/0618/35A/48

Section of power supply cables must be selected in accordance to their length, kind of power
supply and the current absorbed by the unit, as prescribed by current regulations. These
cables must comply with currently applicable standards. In any case we recommend using
shielded cables unless the installer carries out, at his expense, tests that demonstrate that
shielding is not necessary.

Check that power cables are installed with a sufficient distance from alarm cables, from the
network connection cable and from the master-slave connection cable.

On the main power supply line, install a disconnect switch (in overvoltage category III),
please refer to the electric diagram on part 2 manual. Size of main switch must be
determined according to the maximum current consumption of the components (standard +
options). Current absorption data are in the technical data sheets.

Do the same on emergency 48VDC power supply line, if present.

Verify carefully the polarities of DC power supply, according to the wiring diagram.

For 3-phase scroll compressors: take care of correct phase sequence after the connection of
the main power supply. The sequence is important for the correct sense of rotation of the 3-
phase Scroll compressor. A loud noise coming from the compressor means it is turning in the
wrong direction. If this continues for a few hours, it will overheat and irreparably damage the
compressor. Correct compressor operation can be easily checked by measuring the
temperature at the condenser outlet. If this temperature is noticeably higher than the external
temperature, the compressors is working correctly. Otherwise, the compressor is turning in
the wrong direction and the phase sequence must be changed.
The inobservance of these points can provoke damages or malfunction of
components and warranty shall become forthwith void.
For use of leakage-current (FI) circuit breakers, EN 50178 5.2.11.2 must be taken
into account. Only type B pulse-current FI circuit breakers are permitted. FI circuit
breakers do not provide protection against bodily harm during operation of the unit
or frequency converters.

The power lines must be connected to the power terminal board inside the electric panel. To
reach this position, insert the cables in the holes in the connector plate on the roof of the unit,
behind the internal air return opening. Then, follow the route indicated in the drawing on the
next page.

This plate also contains the connectors for the digital output (alarms), analogue input
(humidity probes) and digital input (customer's external devices) signals connected to the
electronic control board, as shown in the drawing on the following page. All digital output
signals are voltage-free type, with the following rating for contacts: maximum allowed voltage
= 24V AC / 48V DC, maximum allowed current = 1A. All digital inputs require a voltage-free
signal from external devices eventually connected to them.
I/O signal connectors C1 and C2 are SUB-D type. ACTADAPT accessory is available as
interface from SUB-D to screw terminals.
All the devices connected to the digital outputs and analogic inputs of the
controller, must be connected to a SELV type power source (voltage limit
42Vdc/ac). The digital inputs of the controller must be connected to voltage-free
contacts.
Please refer to use and maintenance manual part 2 for more information.