Integrated Ignition Control - Lennox G40UH(X) Unit Information

4. Integrated Ignition Control (A92)
78M47 & 100973−01
WARNING
Shock hazard.
Disconnect power before servicing. Control is
not field repairable. If control is inoperable, sim-
ply replace entire control.
Can cause injury or death. Unsafe operation will
result if repair is attempted.
The hot surface ignition control system consisting of an in-
tegrated control board (figure 8 with control terminal des-
ignations in table 7), sensor (figure 10) and ignitor (figure
11). The ignition control board and ignitor work in com-
bination to ensure furnace ignition and ignitor durability.
The ignition control, controls all major furnace operations.
The ignition control also features two LED lights (AN1 red
and AN2 green) for troubleshooting and two accessory
terminals rated at (1) one amp. The ignition control also
features a (3) amp fuse for overcurrent protection. Tables 5
and 6 show jack plug terminal designations. See table 4 for
troubleshooting diagnostic codes. The mini−nitride ignitor
is made from a non−porous, high strength proprietary ce-
ramic material that provides long life and trouble free
maintenance. The ignition control continuously monitors
line voltage and maintains the ignitor power at a consis-
tent level to provide proper lighting and maximum ignitor
life.
TABLE 5
4−Pin Terminal Designation
PIN #
1 Combustion Air Inducer Line
2 Ignitor Line
3 Combustion Air Inducer Neutral
4 Ignitor Neutral
TABLE 6
12−Pin Terminal Designations
PIN #
1 High Limit Output
2 Not Used
3 24V Line
4 Not Used
5 Rollout Switch Out
6 24V Neutral
7 High Limit Input
8 Ground
9 Gas Valve Common
10 Prove Switch In
11 Rollout Switch In
12 Gas Valve Out
FUNCTION
FUNCTION

INTEGRATED IGNITION CONTROL

AN1 AN2
RED GREEN
TERMINAL DESIGNATIONS
COOL
HEAT
PARK
PARK
EAC
XFMR
LINE
HUM
CIRC
XMFR
HUM
LINE
Flame FS
Page 19
FIGURE 8
TABLE 7
120 Volt Hot
Cool Speed
Heat Speed
Park
Park
Electronic Air Cleaner
Transformer
Line
Humidifier
120 Volt Neutral
Blower
Transformer
Humidifier
Line
Flame Signal