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Table 115 — IGC Board Inputs and Outputs
POINT NAME
POINT DESCRIPTION
INPUTS
RT
24 Volt Power Supply
W
Heat Demand
G
Fan
LS
Limit Switch
RS
Rollout Switch
SS
Hall Effect Sensor
CS
Centrifugal Switch (Not Used)
FS
Flame Sense
OUTPUTS
CM
Induced Draft Motor
IFO
Indoor Fan
R
24 Volt Power Output (Not Used)
SPARK
Sparker
LED
Display LED
Table 116 — TR1 Board Inputs and Outputs
TERMINAL TYPE OF I/O
INPUTS
1, 2
24 vac Input Powers TR1
3, 4
5
Not Used
Not Used
Starts Timer no. 2
24 vac Input
6
IDM2 Runs at High Speed
from SC30
MGV2 Operates in High Fire
Starts Timer no. 1
24 vac Input
IDM2 Runs at High Speed
7
from IGC2
MGV2 Operates in Low Fire
Terminal 6 Input ignored during duration of Timer no. 1
OUTPUTS
8, 9
Relay Output MGV2 Operates in High Fire
10, 11
Relay Output Powers SC30
12, 14
Relay Output IDM2 Runs at High Speed
13, 14
Relay Output IDM2 Runs at Low Speed
Table 117 — SC30 Board Inputs and Outputs
TERMINAL
TYPE OF I/O
INPUTS
1
24 vac Input
from TR1
2
7
4-20 mA Input
from SCB
8
OUTPUTS
3
0-20 vdc Output
4
5, 6
Relay Output
SCROLLING MARQUEE
This device is the keypad interface used to access control informa-
tion, read sensor values, and test the unit. The scrolling marquee
display is a 4-key, 4-character, 16-segment LED display as well as
an Alarm Status LED. See Fig. 35.
MODE
Run Status
Service Test
Temperature
Pressures
Setpoints
Alarm Status
Inputs
Outputs
ESCAPE
Configuration
Time Clock
Operating Modes
Alarms
Fig. 35 — Scrolling Marquee
CONNECTOR
PIN NO.
RT,C
2
3
7,8
5,6
1,2,3
9,10
FS
CM
IFO
R
—
RESULT/ACTION
RESULT/ACTION
Powers SC30
Sets Output to Modulating Gas Valve
Output to Modulating Gas Valve
Starts TR1 Timer no. 2
ENTER
The display is easy to operate using 4 buttons and a group of 11
LEDs that indicate the following menu structures:
•
Run Status
•
Service Test
•
Temperatures
•
Pressures
•
Set points
•
Inputs
•
Outputs
•
Configuration
•
Timeclock
•
Operating Modes
•
Alarms
Through the scrolling marquee, the user can access all the inputs
and outputs to check on their values and status. Because the unit is
equipped with suction pressure transducers and discharge satura-
tion temperature sensors, the scrolling marquee can also display
pressures typically obtained from gauges. The control includes a
full alarm history, which can be accessed from the display. In addi-
tion, through the scrolling marquee the user can access a built-in
test routine that can be used at start-up commission and to diag-
nose operational problems with the unit. The scrolling marquee is
located in the main control box and is standard on all units.
SUPPLY FAN
The 48/50P030-050 units are equipped with a single 25 in. x 25 in.
forward-curved fan. The 48/50P055-070 units are equipped with a
single 30 in. x 27 in. forward-curved fan. The 48/50P075-100
units are equipped with either a single 36 in. x 30 in. forward-
curved fan or a 36 in. airfoil fan. The fan sleds are spring isolated
and driven by a single, 3-phase motor. The fan is controlled direct-
ly by the ComfortLink controls.
VARIABLE FREQUENCY DRIVE (VFD)
On units equipped with optional supply fan and/or exhaust fan
VFDs, the fan speed is controlled by a 3-phase VFD. The supply
fan VFD is located in the supply fan section (030-050 size units)
or mixing box section (055-100 size units) behind an access door.
For 055-100 size units with optional VFD power exhaust or return
fan, the related VFD is located in the mixing box section behind
an access door. For 030-050 units, it is located in the supply fan
section. For 075-100 size units with optional high capacity power
exhaust or return fan, the exhaust fan VFD is located in the mixing
box section behind an access door.
The P Series units use ABB VFDs. The VFDs communicate to the
ComfortLink MBB over the local equipment network (LEN). The
VFD speed is controlled directly by the ComfortLink controls
over the LEN. The interface wiring for the VFDs is shown in
Fig. 36 and the terminal designations are shown in Table 118. The
VFD has a keypad display panel that can be used for service diag-
nostics and setting the initial VFD parameters required to allow
the VFD to communicate on the LEN. Additional VFD parame-
ters are set by the ComfortLink controls, and sent to the VFD over
the LEN at power up of the VFD. The VFD faults can be reset
with the VFD keypad or through the ComfortLink controls
(Alarms
R.CUR =Yes).
POWER EXHAUST
The units can be equipped with an optional power exhaust system.
The power exhaust fans are two belt-drive forward-curved fans.
On non-modulating systems, the fans are staged by the
ComfortLink controls based on the economizer damper position.
For modulating (CV or VAV) applications, the fans are turned on
by the ComfortLink controls based on building pressure sensed by
the building pressure transducer. The fan output is modulated via
discharge dampers communicating actuators to maintain the
building pressure set point.
153
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Troubleshooting
