Carrier WEATHERMAKER 48A2 Installation Instructions Manual page 28

a48-8243
FIELD-SUPPLIED THERMOSTAT
RC Y1 Y2
R
Y1 Y2
R
1 2 3
Fig. 20 — Field Control Thermostat Wiring
Staged Gas Control Option Thermistors — If the unit is
equipped with the staged gas heat option, supply-air thermis-
tors must be installed. Three supply-air thermistors are shipped
with staged gas units and are inside the heating section. The
supply-air thermistors should be located in the supply duct
with the following criteria:
• Downstream of the heat exchanger cells
• Equally spaced as far as possible from the heat
exchanger cells
• In a duct location where none of the supply-air thermis-
tors are within sight of the heat exchanger cells
• In a duct location with good mixed supply-air portion of
the unit.
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 configurable tem-
perature set point offset. For variable 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. 21.
Note that when the remote sensor is used, the red jumper
wires provided 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
it is desired to have access to the CCN system through the sen-
sor. If more than one T-55 sensor is being used and averaged,
sensors must be wired in multiples of 4 or 9 as shown in Fig. 22.
T55 SPT
T1
T2
a48-6854
1
3 5
UNIT
TB5
2 4
6
Fig. 21 — Space Temperature Sensor Wiring
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 system. The communication bus
wiring is supplied and installed in the field. Wiring consists of
shielded, 3-conductor cable with drain wire. The system
LIGHT
W1 W2 G C X
W1 W2 G C X
4 5 6 7 8
TB4
T56 SPT
TH C
SN
11 13
9
7 15
8 12
10 14 16
elements are connected to the communication bus in a daisy
chain arrangement. The positive pin of each system element
communication 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
temporarily. There is also an RJ14 LEN (local equipment net-
work) connection that is used to connect a Navigator
download software.
Conductors and drain wire must be 20 AWG minimum
stranded, tinned copper. Individual conductors must be insulat-
ed with PVC, PVC/nylon, vinyl, Teflon, or polyethylene. An
aluminum/polyester 100% foil shield and an outer jacket of
PVC, PVC/nylon, chrome vinyl, or Teflon with a minimum
operating temperature range of –20 C to 60 C (–4 F to 140 F) is
required. Table 9 lists cables that meet the requirements.
Table 9 — CCN Connection Approved Shield Cable
MANUFACTURER
Alpha
American
Belden
Columbia
IMPORTANT: When connecting to CCN communi-
cation bus to system elements, use color coding
system for the entire network to simplify installation
and checkout. See Table 10.
Table 10 — Color Code Recommendations
CCN BUS CONDUCTOR
SIGNAL TYPE
INSULATION COLOR
Positive (+)
Ground
Negative (–)
If a cable with a different color scheme is selected, a similar
color code should be adopted for the entire network. At each
system element, the shields of the communication bus cables
must be tied together. If the communication bus is entirely
within one building, the resulting continuous shield must be
connected to a ground at one point only. If the communication
bus cable exits from one building and enters another, the
shields must be connected to grounds at the lightning suppres-
sor in each building where the cable enters or exits the building
(one point per building only).
To connect the unit to the network:
1. Turn off power to the control box.
2. Cut the CCN wire and strip the ends of the red (+), white
(ground), and black (–) conductors. (If a different net-
work color scheme is used, substitute appropriate colors.)
3. Remove the 3-pin male plug from the base control board
in the main control box, and connect the wires as follows:
a. Insert and secure the red (+) wire to terminal 1 of
the 3-pin plug.
b. Insert and secure the white (ground) wire to termi-
nal 2 of the 3-pin plug.
c. Insert and secure the black (–) wire to terminal 3 of
the 3-pin plug.
4. Insert the plug into the existing 3-pin mating connector on
the base module in the main control box.
VAV Units with Heat — For variable air volume units that
will use heat, the variable air volume terminals should be
interlocked with the unit at TB5 terminals 1 and 2.
28
™
device or
CABLE PART NO.
2413 or 5463
A22503
8772
02525
CCN PLUG PIN
NO.
RED 1
WHITE 2
BLACK 3