Wiring
The SZ1018 use standard terminal designations for wir-
ing. See diagram below.
REMOTE SENSOR WIRING
Use 18 AWG shielded twisted-pair grounded at the sen-
sor mounting location. Sensor wiring runs of up to 250
feet are attainable if properly shielded wire is used and
the installation environment is free of electrical noise.
Sensor wire should be kept at least five feet away from
line voltage wiring.
The SZ1018 accept two remote sensors. Consult the
TS Series Temperature Sensor Submittal Data sheet for
a complete listing of packaging and application styles.
When using TCS Basys Controls three-wire sensors,
use the black and red leads and either clip or twist off
the white lead. Make sure that the dip switches are set
for the sensors you are using.
POWERING THE SZ1018
The SZ1018 are powered from 24 VAC +/- 20 %.
If wiring for communications, dedicated power must be
used to power the SZ1018. Several S-series thermostats
may be powered from the same transformer, provided
that the transformer has sufficient power, although the
polarity must be kept the same throughout because
these are half-wave rectified devices. (SZ1018 thermo-
stats require 8 VA @ 24 VAC).
When the SZ1018 are used as a stand-alone thermostat
without communications, the unit transformer may be
used to power it. However, using separate power will
eliminate possible ground loops which may damage the
thermostat.
Packaged Unit/Modulating Terminations
3
4
4
4
5
5
Zone/Return
Air Temp
Discharge
Air Temp
R
G
Y1
or
W1
Y2
or
W2
Time Clock
Output
+
-
5
Outdoor
Air Temp
7
6
Damper
2
+
6
HWV
or
CWV
A
B
8
8
A
B
1
R
E
F
CAUTION
When multiple TCS devices are
using a single transformer, the
polarity of the power wiring must
be maintained because all TCS
devices are half-wave rectified
and have common return paths.
!
!
1
2
For communication wiring,
use twisted, shielded 18 AWG.
Must be run separately.
Dry momentary contact.
Must not be powered.
24 VAC transformer. See pow-
ering instructions.
3
4
Dry contact. Must not
be powered.
Sensor input wiring 18 AWG,
twisted, shielded pair.
6
7
4 to 20 mA output. 600 ohm max. Do not power actua-
tor with power from the thermostat. The thermostats
are half-wave rectified, whereby the power ground is
common with the signal ground.
Up to nominal 28 VAC from equipment transformer.
Add 500
Ω
resistor (included in bag) to convert 0/4 to
20mA to, 0/2 to 10 VDC.
R
2800 LAURA LANE • MIDDLETON, WI 53562 • (800) 288-9383 • FAX (608) 836-9044 • www.tcsbasys.com
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