Lennonx Furnace G43UF-36B-070-06
#1
10-25-21, 11:55 AM
Lennonx Furnace G43UF-36B-070-06
Lennonx Furnace G43UF-36B-070-06
Furnace cycles through start up and shuts down.
Both the red and green lights stay solid after furnace shuts down
Furnace cycles through start up and shuts down.
Both the red and green lights stay solid after furnace shuts down
#2
10-25-21, 04:12 PM
Group Moderator
Welcome to the forums.
Please explain the cycle in detail.
That code indicates a defective control board.
Power the furnace down for a short while to see if it resets.
One location for service manual.
There is a list of codes near the end of the manual.
Please explain the cycle in detail.
That code indicates a defective control board.
Power the furnace down for a short while to see if it resets.
One location for service manual.
There is a list of codes near the end of the manual.
Last edited by PJmax; 10-25-21 at 04:32 PM.
#3
10-26-21, 09:44 AM
Thanks Pete.
1. The thermostat calls for heat
2. Furnace starts
3. The motor sounds like it starts
4. You can see the heating element glowing (5-6 sperate times)
5. The red & green lights indicate normal operation
6. The furnace shuts down
7. Red & green lights are solid
I have a video, but this forum won't upload the zip file.
1. The thermostat calls for heat
2. Furnace starts
3. The motor sounds like it starts
4. You can see the heating element glowing (5-6 sperate times)
5. The red & green lights indicate normal operation
6. The furnace shuts down
7. Red & green lights are solid
I have a video, but this forum won't upload the zip file.
#5
10-26-21, 05:29 PM
Group Moderator
The system follows logic. After the igniter heats up..... if the flame doesn't light.... the board is supposed to pause and reset. Some will turn the inducer off and then back on. You said the igniter glows 5-6 times..... how far apart are the cycles ?
The trade site says red and green locked on indicate a defective board.
If I was there working on that furnace I'd have my voltmeter connected to the gas valve to monitor for 24vAC. It would only be there for a few seconds.... you should hear a click.... the burner would light or the igniter would immediately go out.
You'd need to put your video on you tube and link it here.
The trade site says red and green locked on indicate a defective board.
If I was there working on that furnace I'd have my voltmeter connected to the gas valve to monitor for 24vAC. It would only be there for a few seconds.... you should hear a click.... the burner would light or the igniter would immediately go out.
You'd need to put your video on you tube and link it here.
#6
10-27-21, 02:29 PM
Here is a short 25 sec video showing the igniter glowing and the red & green lights in the normal 'call for heat' setting
https://youtu.be/82SZkHx8Kbc
Here is the full start up cycle (6.5 minutes long). At the end I show the red & green lights solid after the furnace shuts down.
https://youtu.be/PzRI8-pRmt8
The igniter glows 5-6 times with an interval of approx. 14 seconds on and 14 seconds off
https://youtu.be/82SZkHx8Kbc
Here is the full start up cycle (6.5 minutes long). At the end I show the red & green lights solid after the furnace shuts down.
https://youtu.be/PzRI8-pRmt8
The igniter glows 5-6 times with an interval of approx. 14 seconds on and 14 seconds off
#7
10-27-21, 06:31 PM
Group Moderator
Those videos are listed as private. You can make them unlisted so that we can see them from your link but they aren't advertised by you tube.
#9
10-28-21, 06:18 PM
Group Moderator
Yes..... the videos were viewable.
That board must be bad.
I lost track of igniter warm up periods but any more than four times should.... I believe...... shut the board down for one hour. If the board doesn't shut down.... it should at least lockup, reset in one hour and repeat the cycle.
Heating Sequence Of Operation
1 - When thermostat calls for heat, combustion air inducer starts.
2 - Combustion air pressure switch proves blower operation,
........... switch is factory set and requires no adjustment.
3 - After a 15-second prepurge, the hot surface igniter energizes,
4- After a 20-second igniter warm-up period, the gas valve solenoid opens.
5 - Gas is ignited, flame sensor proves the flame, and the combustion process continues.
6 - If flame is not detected after first ignition trial, the ignition control will repeat steps 3 and 4
........... four more times before locking out the gas valve ("WATCHGUARD" flame failure mode).
...........The ignition control will then automatically repeat steps 1 through 6 after 60 minutes.
7 - To interrupt the 60-minute "WATCHGUARD" period, move thermostat from "Heat" to "OFF"
...........then back to "Heat", Heating sequence then restarts at step 1,
That board must be bad.
I lost track of igniter warm up periods but any more than four times should.... I believe...... shut the board down for one hour. If the board doesn't shut down.... it should at least lockup, reset in one hour and repeat the cycle.
Heating Sequence Of Operation
1 - When thermostat calls for heat, combustion air inducer starts.
2 - Combustion air pressure switch proves blower operation,
........... switch is factory set and requires no adjustment.
3 - After a 15-second prepurge, the hot surface igniter energizes,
4- After a 20-second igniter warm-up period, the gas valve solenoid opens.
5 - Gas is ignited, flame sensor proves the flame, and the combustion process continues.
6 - If flame is not detected after first ignition trial, the ignition control will repeat steps 3 and 4
........... four more times before locking out the gas valve ("WATCHGUARD" flame failure mode).
...........The ignition control will then automatically repeat steps 1 through 6 after 60 minutes.
7 - To interrupt the 60-minute "WATCHGUARD" period, move thermostat from "Heat" to "OFF"
...........then back to "Heat", Heating sequence then restarts at step 1,
