19W94 -- LB-84495B 33J62 IGNITION CONVERSION KIT

         
Some Lennox 80MGF and G24M Series furnaces use the EGC direct spark integrated ignition control. The EGC controls and monitors the entire sequence of operation. On a call for heat from the thermostat the control monitors the combustion air blower pressure switch.

The control will not begin the heating cycle if the pressure switch is closed (by-passed). Once the pressure switch is determined to be open, the combustion air blower is energized. When the differential in pressure across the pressure switch is great enough, the pressure switch closes and a 15 second pre-purge period  begins. After the pre-purge period, the gas valve will open and ignition (spark) will be attempted for 10 seconds. After ignition, the control initiates a ten second flame stabilization period. The flame stabilization period allows the burners to heat up and the flame to stabilize. Once flame is established, the control will constantly monitor the burner flame using flame rectification. Flame failure response time is 0.8 seconds.

If the initial attempt for ignition fails, the sequence is repeated up to five times. After the fifth trial, the control goes into "Watchguard". During watchguard mode, the entire unit will be de-energized for one hour. After one hour the control will repeat the ignition sequence. Watchguard may be manually reset by breaking and remaking thermostat demand.

NOTE−If flame is established beyond the 10 second flame stabilization period then lost, the control resets for five more ignition trials. The control can be reset five times during one unsatisfied thermostat demand, providing a maximum of 25 trials for ignition