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54
Integrated Gas Control (IGC) Board
The IGC is provided on gas heat units. (See Fig. 21 and Table 24.)
The IGC controls the direct spark ignition system and monitors the
rollout switch, limit switch, and induced-draft motor Hall Effect
switch.
The IGC is equipped with an LED (light-emitting diode) for
diagnostics. See the Troubleshooting section for more information.
RED LED-STATUS
C07028
Fig. 21 -- Integrated Gas Control (IGC) Board
Table 24 — IGC Connections
TERMINAL
LABEL
POINT DESCRIPTION
SENSOR LOCATION
TYPE OF I/O
CONNECTION
PIN NUMBER
INPUTS
RT, C
Input power from TRAN 1
control box
24 VAC
SS
Speed sensor
gas section
analog input
J1, 1---3
FS, T1
Flame sensor
gas section
switch input
W
Heat stage 1
MBB
24 VAC
J2, 2
RS
Rollout switch
gas section
switch input
J2, 5---6
LS
Limit switch
gas section
switch input
J2, 7---8
CS
Centrifugal switch (not used)
switch input
J2, 9---10
OUTPUTS
L1, CM
Induced draft combustion motor
gas section
line VAC
IFO
Indoor fan request
control box
relay
J2, 1
GV (W1)
Gas valve (heat stage 1)
gas section
relay
J2, 12
GV (W2)
Gas Valve (heat stage 2, from MBB)
gas section
Not on IGC
48/
50P
D