Field Control Wiring - Carrier 50AJ/AK/AM020 Installation Instructions Manual

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IMPORTANT: On 208/230-v units, transformers 1-5
are wired for 230-v. If 208/230-v unit is to be run with
208-v power supply, the transformers must be rewired
as follows:
For transformer 1 move the black wires connected to termi-
nal H2 and connect it to terminal H3.
For transformers 2-4, that are used for the 24 volt control
circuits, connect as follows:
1. Remove cap from red (208 v) wire.
2. Remove cap from spliced orange (230 v) wire. Discon-
nect orange wire from black unit power wire.
3. Cap orange wire.
4. Splice red wire and black unit power wire. Cap wires.
If the unit is equipped with the optional convenience outlet
connect the yellow wire to H2 on transformer 5.
IMPORTANT: BE CERTAIN UNUSED WIRES ARE
CAPPED. Failure to do so may damage the transformers.
FIELD CONTROL WIRING — The 50A series units sup-
port a large number of different modes of operation as well as
factory-installed options and field-installed accessories that
will impact the field control wiring. Refer to Fig. 16-25.
The control options that the unit can provide are based on
the following parameters:
• CV (constant volume), VAV (Variable Air Volume), VVT®
(Variable Volume Variable Temperature) or Carrier TEMP
system.
• Standalone with a thermostat (CV) or with a space sensor
(CV and VAV)
• Network Application with Carrier CCN or other networks
• Demand Ventilation with CO
• Economizer and Economizer with Changeover control
• Building and Duct 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.
T-STAT (Conventional Thermostat) — Unit can be con-
trolled 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 ComfortLink™ controls.
Install thermostat according to the installation instructions
included with accessory thermostat. Locate thermostat assem-
bly on a solid interior wall in the conditioned space to sense av-
erage temperature.
Route thermostat cable or equivalent single leads of colored
wire from subbase terminals through conduit into unit to low
voltage connection in the main control box, as shown in Fig. 19
and 20. For thermostat TB4 connections see Fig. 16.
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:
STAGE 1
SIZE
(W1) ON
020-050
060
sensor
2
STAGE 2
(W1 & W2) ON
0.24 0.13
0.36 0.13
FIELD SUPPLIED THERMOSTAT
RC Y1
R
Y1
R
Fig 16 — Field Control Thermostat Wiring
T55 SPT
T1
T2
1
3
UNIT
TB5
2 4
Fig. 17 — T55 or T56 Wiring
Settings may be changed slightly to provide a greater degree of
comfort for a particular installation.
SPT (Space Temperature Sensor) — For constant volume ap-
plications the ComfortLink 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 ± 5 F temperature
set point offset at the thermostat. For variable air volume appli-
cations only the T55 sensor can be used.
Install sensor according to the installation instructions in-
cluded with accessory sensor. Locate sensor assembly on a sol-
id interior wall in the conditioned space to sense average tem-
perature.
Run wiring to the space sensor as shown in Fig. 17.
Note that when the remote sensor is used, the red jumper
wires must be connected from TB4 terminal 4 to 5 and TB4
terminal 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
more than 1 sensor is being used and averaged, sensors must be
wired in multiples of 4 or 9 as shown in Fig. 18.
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 Interface — The rooftop units can
be connected to the CCN. The communication bus wiring is
supplied and installed in the field. Wiring consists of shielded,
3-conductor cable with drain wire. The system elements are
connected to the communication bus in a daisy chain arrange-
ment. The positive pin of each system element communication
connector must be wired to the positive pins of the system ele-
ment 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 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 Navigator™ display or field service computer. There
is also another RJ14 LEN connection that is used to download
software.
28
LIGHT
Y2 W1 W2 G C
Y2 W1 W2 G C
TB4
T56 SPT
TH C
SN
11 13
5 9
7
8 12
6 10 14
X
X
15
16