70
Integrated Gas Control (IGC) Board
The IGC is provided on gas heat units. The IGC controls the
direct spark ignition system and monitors the rollout switch,
limit switch, and flue gas pressure switch. See Fig. 38 and
Table 29.
Fig. 38 — Integrated Gas Control (IGC) Board
Table 29 — Integrated Gas Control (IGC) Board Connections
TERMINAL
LABEL
POINT DESCRIPTION SENSOR LOCATION TYPE OF I/O
CONNECTION
PIN NUMBER
Inputs
RT, C Power for IDR on 575v units Control box 24 VAC Spade
C Input power common Spade
SS Speed sensor Gas section Analog input J1, 1-3
FS, T1 Flame sensor Gas section Switch input Spade
W Heat stage 1 Call MBB to IGC 24 VAC J2, 2
G Indoor Fan Call Not used 24 VAC J2, 3
R Input power from TRAN 1 TB4 to IGC 24 VAC J2, 4
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 or relay Gas section Line VAC
IFO Indoor fan request IGC to MBB Relay J2, 1
GV (W1) Gas valve (heat stage 1) Gas section Relay J2, 12
GV (W2) Gas Valve (heat stage 2, from CTB) Gas section Not on IGC
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