24
4. Splice red wire and black unit power wire. Cap wires.
If the unit is equipped with the optional convenience outlet, con
-
nect the yellow wire to H2 on transformer 5.
FIELD CONTROL WIRING
The 50A Series units support a large number of control options
that can impact the field control wiring. See Fig. 21 and 22.
The control options that the unit can provide relate to the follow
-
ing parameters:
• CV (constant volume), VAV (variable air volume), SAV
(staged air volume), or VVT
®
(variable volume and vari
-
able temperature) control operation
• Standalone with a thermostat (CV) or with a space sensor
(CV and VAV)
• Network application with CCN (Carrier Comfort Network
®
)
or other networks
• Demand controlled ventilation with CO
2
sensor
• Economizer and economizer with changeover control
• Building and duct static pressure control
• Fire shutdown and smoke control
• Diagnostics and monitoring
• For constant volume applications a thermostat (T-Stat) or
space temperature sensor (SPT) will be required.
Fig. 21 —
Field Control Thermostat Wiring
Fig. 22 —
Space Temperature Sensor Wiring
T-STAT (Conventional Thermostat)
Unit can be controlled with a Carrier-approved accessory electro-
mechanical or electronic thermostat that has two stages of cooling,
two stages of heating control, and an output for indoor fan control.
It may also include time of day scheduling or use the scheduling
routines built into the
Comfort
Link controls.
Install thermostat according to the installation instructions in
-
cluded with accessory thermostat. Locate thermostat assembly
on a solid interior wall in the conditioned space to sense average
temperature.
Route thermostat cable or equivalent single leads of colored wire
from sub-base terminals through conduit into unit to low voltage
connection in the main control box, as shown in Fig. 21 and 22.
For thermostat TB4 connections see Fig. 21.
NOTE: For wire runs up to 50 ft, use no. 18 AWG (American
Wire Gage) insulated wire (35 C minimum). For 50 to 75 ft, use
no. 16 AWG insulated wire (35 C minimum). For over 75 ft, use
no. 14 AWG insulated wire (35 C minimum). All wire larger than
no. 18 AWG cannot be directly connected at the thermostat and
will require a junction box and splice at the thermostat. Set heat
anticipator settings as follows:
Settings may be changed slightly to provide a greater degree of
comfort for a particular installation.
SPT (Space Temperature Sensor)
For constant volume applications the
Comfort
Link controls can
also be used with T55 and T56 space temperature sensors that use
a 10K thermistor. The T56 sensor also has the capability for a con
-
figurable temperature set point offset at the thermostat. For vari
-
able air volume applications only the T55 sensor can be used.
Install sensor according to the installation instructions included
with accessory sensor. Locate sensor assembly on a solid interior
wall in the conditioned space to sense average temperature. Run
wiring to the space sensor as shown in Fig. 22.
NOTE: When the remote sensor is used, the red jumper wires pro
-
vided must be connected from TB4 terminal 4 to 5 and TB4 termi
-
nal 5 to 1.
Both the T55 and T56 have a CCN communications port and this
should be wired to the CCN Communications TB3 board if it is
desired to have access to the CCN system through the sensor. If
more than one T55 sensor is being used and averaged, sensors
must be wired in multiples of 4 or 9 as shown in Fig. 23.
T58 Communicating Thermostat
Carrier also has a fully communicating thermostat which, if
used, will be wired to the CCN communication connections on
TB3 as described in the Carrier Comfort Network
®
Interface
section below.
Carrier Comfort Network (CCN) Interface
The rooftop units can be connected to the CCN system. The com
-
munication bus wiring is supplied and installed in the field. Wiring
consists of shielded, 3-conductor cable with drain wire. The sys
-
tem elements are connected to the communication bus in a daisy
chain arrangement. The positive pin of each system element com
-
munication connector must be wired to the positive pins of the
system element on either side of it, the negative pins must be
wired to the negative pins, and the signal pins must be wired to
signal ground pins. Wiring connections for CCN system should be
made at the TB3 terminal block using the screw terminals. The
TB3 board also contains an RJ14 CCN plug that can be used to
connect a field service computer or other CCN device. There is
also an RJ14 LEN (local equipment network) connection that is
used to connect a Navigator™ display or download software.
IMPORTANT: BE CERTAIN UNUSED WIRES ARE
CAPPED. Failure to do so may damage the transformers.
TB4
a48-8243
R
Y1
Y2
W1
W2
G
C
X
R
Y1
Y2
W1
W2
G
C
X
FIELD-SUPPLIED THERMOSTAT
LIGHT
RC
1
2
3
4
5
6
7
8
TB4
a48-6854
T1
T2
1
2
4
3
5
6
7
8
9
10
11
12
13
14
15
16
TH
C
SN
T56 SPT
T55 SPT
UNIT
TB5
UNIT SIZE
50A
STAGE 1
(W1) ON
STAGE 2
(W1 AND W2) ON
020-050
0.24
0.13
060
0.36
0.13