Variable Air Volume (Vav) Units; Option And Accessory Control Wiring - Carrier WeatherExpert 48N2 Installation Instructions Manual

Route thermostat cable or equivalent leads of colored wire
from subbase terminals through conduit into the low voltage
connections in the main control box. For thermostat TB201
connections, see Fig. 46.
NOTE: For wire runs up to 50 ft, use no. 18 AWG (American
Wire Gage) 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.
FIELD SUPPLIED THERMOSTAT
a48-8735
RC Y1 Y2
R
Y1 Y2
R
TB201
Fig. 46 — Field Control Thermostat Wiring
Variable Air Volume (VAV) Units —
units may be used in applications with additional control fea-
tures, options, or accessories. Refer to the appropriate accesso-
ry installation instructions for more information on installing
that accessory. Refer to the Controls and Troubleshooting man-
ual for more information concerning installation and configura-
tion of options and accessories. Control options and accessories
available for VAV units are:
• thermostats
• differential enthalpy sensor
• return air humidity sensor
• outdoor air humidity sensor
• relative humidity space sensor
• CO sensors
2
• fan status switch
• filter pressure transducer
• return smoke detector
• CEM (controls expansion module)
• EXB (economizer control board) module
VAV CONTROL WIRING — The recommended types of
control wiring are shown below:
MANUFACTURER
Regular Wiring
Alpha
American A21451
Belden
Columbia D6451
Manhattan M13402
Quabik
SENSORS — Sensors should be wired using single twisted
pairs of 20 AWG (American Wire Gage) conductor cable rated
for the application, except for the T-56 accessory sensor which
requires 3-conductor cable.
HUMIDITY CONTROL AND HOT WATER AND
STEAM VALVES — These devices require 20 AWG twisted
pair conductor cables rated for the application for the 4 to
20 mA signal.
SPACE TEMPERATURE SENSOR (T-55) — The
temperature sensor (P/N 33ZCT55SPT), if used, is wired to
terminals in the unit main control box. To connect the space
temperature sensor, see Fig. 47.
SPACE TEMPERATURE SENSOR (T-56) — The
temperature sensor (P/N 33ZCT56SPT), if used, is wired to
terminals in the unit main control box. To connect the space
temperature sensor, see Fig. 47.
W1 W2 G
W1 W2 G C
The 48N
PART NO.
Plenum Wiring
1895 —
A48301
8205 884421
—
M64430
6130 —
COMMUNICATING SPACE TEMPERATURE SENSOR
(T-58) — The communicating space temperature sensor (P/N
33ZCT58SPT) is wired to the Carrier Comfort Network
(CCN) connections on TB202.
SPACE TEMPERATURE AVERAGING — Applications
that require averaging using multiple space temperature sen-
sors can be satisfied using either 4 or 9 sensors as shown in Fig.
48.
NOTE: Only Carrier sensors may be used for standard T-55
space averaging. Sensors must be used in multiples of 1, 4, and
9 only, with total sensors wiring not to exceed 1000 ft.
NOTE: Do not use T-56 sensors for space temperature averag-
ing because the 5-degree offset function will not work in a
multiple sensor application.
HEAT INTERLOCK RELAY (VAV Units Only — Not Neces-
sary for Digital Air Volume Applications) — Variable air vol-
X
ume (VAV) units using morning warm-up and/or occupied
heating require that room terminals be controlled to a position
that provides the minimum required heating cfm or greater
when the unit goes into Heating mode. The HIR (heat interlock
relay) function is provided for this control. When the unit goes
into Heating mode, the HIR is energized to provide switch clo-
sure or opening (depending on how the field-supplied power
source is set up) to open the room terminals. The field connec-
tions for the HIR are at TB201 terminals 9 and 10. See Fig. 49.
Option and Accessory Control Wiring —
The 48N Series units may be used in applications with addi-
tional control features, options, or accessories. Refer to the
Controls, Start-Up, Operation, Service and Troubleshooting
manual for more information concerning installation and con-
figuration of options and accessories. Figures 49-59 contain
wiring information on the following features:
• heat interlock relay (Fig. 49)
• outdoor air enthalpy switch (Fig. 50)
• CO space sensor (Fig. 51)
2
• filter status switch (Fig. 52)
• fan status switch (Fig. 53)
• space humidity sensor (Fig. 54)
• return air humidity sensor (Fig. 54)
• return air CO
• return air smoke detector (Fig. 56)
• smoke control — fire shutdown (Fig. 57)
• smoke control — purge (Fig. 58)
• smoke control — evacuation (Fig. 58)
• smoke control — pressurization (Fig. 58)
• CCN connections (Fig. 59)
a48-8736
1
UNIT
TB201
2
space
space
Fig. 47 — T-55 or T-56 Wiring
38
sensor (Fig. 55)
2
T55- SPT T56- SPT
SEN
SEN
11
3 5 9
7
4
8 12
6 10
T55
TB201
1 2
3
®
JUMPER
TERMINALS
SET
13
15
14 16