Low Voltage Terminal Board; Communication Interface Board (Cib); Central Terminal Board (Ctb) - Carrier 48LC 04 Controls, Start-Up, Operation And Troubleshooting

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 DISPLAY
LABEL NAME*
C--- 2
R--- 2
SPT+ SPT
SPT--- SPT
SPTO SPTO
FDWN FDWN
X ALRM
G G
W1 W1
W2 W2
Y1 Y1
Y2 Y2
RAT RAT
SAT SAT
HUM HUM
LPWR
COM
IAQ IAQ
SPRH SP .RH or OAQ
RMOC RM.OC
ENTH or
ENTH
IAQ.S
*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
connector or the CCN screw terminals allow building
communication connections. See Fig. 19.
LEN CCN
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.
DESCRIPTION
Transformer 2 Common
24 VAC power Transformer 2
Space temperature (T55/56)
Space temperature (T55/56)
Space temperature offset (T56)
Fire shutdown switch input
Alarm output (normally open)
Thermostat G (Fan)
Thermostat W1 (1st stage heat)
Thermostat W2 (2nd stage heat)
Thermostat Y1 (1st stage cool)
Thermostat Y2 (2nd stage cool)
Return Air Temperature Sensor
Supply Air Temperature Sensor
Humidistat switch input
Analog Sensor Loop power (24vdc)
Analog sensor common
Indoor air quality sensor
Relative humidity sensor or
Outdoor air quality sensor
Remote occupancy switch
Outdoor enthalpy switch, or
Indoor air quality switch
Not Used
R (CCN) RJ- -11
(+) (com) (-) shield
CCN
C11508
SENSOR
LOCATION
24 VAC common
space 10k thermistor
space 10k thermistor
space 10k thermistor
supply/return/space
space 24 VAC output
space
space
space
space
space
return section 10k thermistor
Blower or duct 10k thermistor
supply/return/space
return/space 4--- 20 mA input
field installed 4--- 20 mA input
field installed
economizer, or
return/space
Fig. 20 - - Central Terminal Board (CTB)
54
TERMINAL NUM-
TYPE OF I/O
BER
1,2
24 VAC 9,10
14
13
12
24 VAC input 30
3
24 VAC input 4
24 VAC input 5
24 VAC input 6
24 VAC input 7
24 VAC input 8
15,16
17,18
switch input 27
24 VDC 24
Ground 22
23
21
24 VAC input 25
24 VAC input 26
11,19,20,28,29
C11509