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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a Lennox 80MGF4/5X-100A-5. It was working

Customer Question

Customer: I have a Lennox 80MGF4/5X-100A-5. It was working intermittently last year, then stopped. However, it works just fine if I go into the attic, remove the panel, and light it manually with a bbq lighter when my wife turns on the thermostat from down below.
JA: Thanks. Can you give me any more details about your issue?
Customer: basically, it only works if I light it manually right after the thermostat is turned on. I just wait until I hear the igniter clicking, then light the burners.
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Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.

Thanks for the information,

So far it sounds like the igniter is bad (90% chance if it is a glow plate type), or a bad printed circuit board.

Please attach a well focused, close up photo of the wiring diagram glued inside the service panel, the picture needs to be taken from straight on, in very good light.

You can use the paper clip- icon at the right end of the tool bar at the top of this dialog box to attach ithere.,Include a picture of the thermostat wire connections to the printed circuit board in the same area.

If you have an error code showing, tell me what the code read out is on the wiring diagram or a sticker next to the diagram please.

If there is no paper clip-icon, look for the '+attachfiles'link at left of your send button.

I can mark it up with trouble shooting instructions.

We can go from there.