ignition problem

My furnace is Lennox G23 Series, about 11 years old.

Recently it has ignition problem. Basic it just failed to ignite when necessary. There is no air flow from the supply vent. But the furnace seems keep running.(there is some noise seem the fan is still running?). I had my furnace clean checked 2 months ago.

It happend twice 1 week ago. Each time, I turned the power off and then turned it on after 10 minutes, it resumed normal. I called a contractor and he came to check it. He just cleaned a little bit the flame sensor and said should be ok since he didn't see anything wrong.

But it happend again today, turn it off and turn it on works again. I am afraid there is something wrong. What could be wrong? Should I call the contractor again to check?

Thanks very much.

 

There is no air flow from the supply vent seems to be a problem.
is the fan running or is it humming. if it is humming the the fan motor maybe defective although it could be a start capacitor. but the again it could a relay or even a circuit board. sometimes one has to be there when it malfuctions

 

it is humming. but no air flow.

 

it sounds like a defective motor
it is possible that it needs a start capacitor or start windingS
if the motor hums and doesnt blow.
i suggest calling a professional out

 

I'm not familiar with that model specifically but I want to be sure we are all on the same page. If the furnace has an inducer fan, that will run any time the safety control sees a fault. If the inducer fan is running and cycling the power switch gets the unit throwing heat again, it seems like a flame sensor problem. If the inducer fan is humming and not running, the problem lies with the inducer fan. I don't think the house air blower will come on if the furnace doesn't light up. I could be wrong (I have been wrong before), but I wanted to spark some conversation before you go and call a tech.

Ken