Carrier WeatherExpert 48N2 Controls, Start-Up, Operation, Service, And Troubleshooting page 158

BOARD NO. TERMINAL NO.
TB203 - FIELD CONNECTIONS CEM (in Main Control Box)
1
2
3
4
5
TB203
6
7
8
—
—
LEGEND
IAQ — Indoor Air Quality
VAV — Variable Air Volume
POINT NAME
INPUTS
RT
W
G
LS
RS
SS
CS
FS
OUTPUTS
CM
IFO
R
SPARK
LED
TERMINAL
INPUTS
1, 2
3, 4
5
6
7
OUTPUTS
8, 9
10, 11
12, 14
13, 14
CURRENT SENSOR BOARD (CSB)
This board monitors the status of the compressor by sensing
the current flow to the compressors and then provides digital
status signal to the MBB and CXB.
TIMER RELAY CONTROL BOARD (TR1)
The TR1 is used on modulating gas heat equipped units only. It
is located in the gas heat section and is used in combination with
the SC30 to provide control of the modulating gas heat section.
The TR1 receives an input from the IGC, initiates a start-up se-
quence, powers the SC30, sets the induced-draft motor speed,
and provides the main gas valve high fire input. When the start-
up sequence is complete, the TR1 checks the input from the
SC30 to determine which state to command the induced-draft
Table 103 — Field Terminal Connections (cont)
DESCRIPTION
Filter Pressure Switch/Sensor - Return (+)
Filter Pressure Switch/Sensor - Return (-)
Filter Pressure Switch/Sensor - Supply (+)
Filter Pressure Switch/Sensor - Supply (-)
Filter Pressure Sensor - Return (+24 VDC)
Filter Pressure Sensor - Supply (+24 VDC)
Mixed Air Humidity Sensor (+24 VDC)
Mixed Air Humidity Sensor (-)
Humidifier Output
Humidifier Output
Table 104 — IGC Board Inputs and Outputs
POINT DESCRIPTION
24 Volt Power Supply
Heat Demand
Fan
Limit Switch
Rollout Switch
Hall Effect Sensor
Centrifugal Switch (Not Used)
Flame Sense
Induced Draft Motor
Indoor Fan
24 Volt Power Output (Not Used)
Sparker
Display LED
Table 105 — TR1 Board Inputs and Outputs
4 20 mA loop when used with 180 Ohm resistor
4 20 mA signal when used with 180 Ohm resistor
4 20 mA loop when used with 180 Ohm resistor
4 20 mA signal when used with 180 Ohm resistor
4 20 mA loop power
4 20 mA loop power
4 20 mA loop power
4 20 mA signal
Contact (maximum 24 vac, 3 A) Violet Wire/Spade Terminal
Contact (maximum 24 vac, 3 A) Violet Wire/Spade Terminal
TYPE OF I/O
24 Vac Input
Not Used
24 Vac Input
from SC30
24 Vac Input
from IGC2
Relay Output
Relay Output
Relay Output
Relay Output
motor and main gas valve. See Table 105 for TR1 inputs and
outputs. The TR1 has status LEDs on the front cover. See
Table 106 for TR1 status LED descriptions.
SIGNAL CONDITIONER CONTROL BOARD (SC30)
The SC30 is used on modulating gas heat equipped units only.
It is located in the gas heat section and is used in combination
with the TR1 to provide control of the modulating gas heat sec-
tion. The SC30 is powered by an output from the TR1. It re-
ceives a capacity input from the SCB, provides a capacity out-
put to the modulating gas valve, and provides an output to the
TR1 to determine which state to command the induced-draft
motor and main gas valve. See Table 107.
158
TYPE
CONNECTOR
PIN NO.
RT,C
2
3
7,8
5,6
1,2,3
9,10
FS
CM
IFO
R
—
RESULT/ACTION
Powers TR1
Not Used
Starts Timer no. 2
IDM2 Runs at High Speed
MGV2 Operates in High Fire
Starts Timer no. 1
IDM2 Runs at High Speed
MGV2 Operates in Low Fire
Terminal 6 Input ignored during duration of
Timer no. 1
MGV2 Operates in High Fire
Powers SC30
IDM2 Runs at High Speed
IDM2 Runs at Low Speed