Unit installation

52
Low Voltage Terminal Board (TB)
The field connection terminal board has 30 terminals oriented in 3
rows of 10 terminals. The front has screw terminals and the back has
spade connectors. This board provides connection fo the thermostat,
space sensor, and most field installed accessories. See Table 19.
Table 19 – Field Connection Terminal Board (TB) Connections (04--14 Size Units)
TERMINAL
LABEL
DISPLAY
NAME*
DESCRIPTION
SENSOR
LOCATION
TYPE OF I/O
TERMINAL NUM-
BER
C --- 2 Transformer 2 Common 24 VAC common 1,2
R --- 2 24 VAC power Transformer 2 24 VAC 9,10
SPT+ SPT Space temperature (T55/56) space 10k thermistor 14
S P T --- SPT Space temperature (T55/56) space 10k thermist or 13
SPTO SPTO Space te mperature offset (T56) space 10k thermistor 12
FDWN FDWN Fire shutdown switch input supply/return/space 24 VAC input 30
X ALRM Alarm output (normally open) space 24 VAC output 3
G G Thermostat G (Fan) space 24 VAC input 4
W1 W1 Thermostat W1 (1st stage heat) space 24 VAC input 5
W2 W2 Thermostat W2 (2nd stage heat) space 24 VAC input 6
Y1 Y1 Thermostat Y1 (1st stage cool) space 24 VAC input 7
Y2 Y2 Thermostat Y2 (2nd stage cool) space 24 VAC input 8
RAT RAT Return Air Temperature Sensor return section 10k thermistor 15,16
SAT SAT Supply Air Temperature Sensor Blower or duct 10k thermistor 17,18
HUM HUM Humidistat switch input supply/return/s pace switch input 27
LPWR Analog Sensor Loop power (24vdc) 24 VDC 24
COM Analog sensor common Ground 22
IAQ IAQ Indoor air quality sensor return/space 4 --- 2 0 m A i n p u t 23
SPRH SP.RH or OAQ
Relative humidity sensor or
Outdoor air quality sensor
field installed 4 --- 2 0 m A i n p u t 21
RMOC RM.OC Remote occupancy switch field installed 24 VAC input 25
ENTH
ENTH or
IAQ.S
Outdoor enthalpy switch, or
Indoor air quality switch
economizer, or
return/space
24 VAC input 26
Not Used 11,19,20,28,29
*Point name displayed on the Scrolling Marquee or Navigator .
Communication Interface Board (CIB)
This circuit board provides a field connection point for unit
communications. The Local Equipment Network (LEN) RJ--11
connector allows a handheld Navigator to be plugged in to access
the unit’s menus. The Carrier Comfort Network
R
(CCN) RJ--11
connector or the CCN screw terminals allow building
communication connections. See Fig. 19.
1 2
3
4
LEN CCN
CCN
(+) (-)(com) shield
C11508
Fig. 19 -- Communications Interface Board (CIB)
Central Terminal Board (CTB)
This circuit board is a simple trace board that serves as a junction
point between components and the ComfortLink system. It is the
distribution center for transformer 1’s power. The integrated gas
controller (IGC), electric heater control, compressor control, and
unit shutdown all feed through this trace board. See Fig. 20 and
Table 20 for the connections through this board.
C11509
Fig. 20 -- Central Terminal Board (CTB)
48/50LC