Lennox KGC Series Unit Information page 25

INTEGRATED CONTROL BOARD A3
11-Burner Control A3
WARNING
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at disconnect
switch(es). Unit may have multiple power
supplies.
The burner control A3 is located in the gas heat section.
See FIGURE 17.
The ignition control provides four main functions: gas
valve control, blower control, ignition and flame sensing.
The control has a green LED to show control status
(TABLE 5). The unit will usually ignite on the first trial
and A3 allows three trials for ignition before locking out.
The lockout time is 1 hour. After lockout, the ignition
control automatically resets and provides three more
attempts at ignition. Manual reset after lockout requires
removing power from the control for more than 1 second
or removing the thermostat call for heat for more than 1
second but no more than 20 seconds. 24 volt thermostat
connections (P2) and heating component connections
(J1) are made through separate jackplugs. See TABLE
6 for thermostat terminations and TABLE 7 for heating
component terminations
TABLE 5
LED
Slow Flash Normal operation. No call for heat
Fast Flash Normal operation. Call for heat
Internal Control Fault, No Power To
Steady Off
Board or Gas Valve Relay Fault
Steady On
Lockout. Failed to detect or sustain
2 Flashes
Rollout switch open / Prove switch open
3 Flashes
4 Flashes Primary High Limit switch open
5 Flashes Flame sensed but gas valve not open.
6 Flashes On Board Microprocessors Disagree
STATUS
Control Internal Failure
flame
or closed
P2 TERMINAL DESIGNATIONS
PIN #
1
2
3
4
5
6
7
J1 TERMINAL DESIGNATIONS
PIN #
1
2
3
4
5
6
Page 25
TABLE 6
Function
R 24 Volts to thermostat
W1 Heat Demand
Y Cool Demand
C Common
G Indoor Blower
BL OUT Indoor Blower Relay
W2 Second Stage Heat
TABLE 7
Function
Limit Switch Out
Rollout Switch / Prove Switch Out
Gas Valve Common
Gas Valve Out
Rollout Switch / Prove Switch In
Limit Switch In