pilot lights, ignitor clicks, burner doesn't

[DDS]

I hope someone can help, its cold in Canada!

My Lennox gas furnace ignitor fires, the pilot lights, and it sounds as though the ignitor continues to fire (that piezo clicking noise ztztztztztztztztzttzzt) while the pilot is lit. Then a relay clicks and the pilot goes out again. The cycle repeats several minutes later. It's as though the furnace hasn't figured out that the pilot is lit, and turns itself off. I note a wire to the control/relay unit marked 'sense' from what appears to be a thermocouple that is parked in the pilot flame next to the ignitor. Is this the problem? Am I getting warm? (actually, quite the opposite!) I'll double check the thermocouple connections. As you may have guessed I know nothing at all about HVAC.

Many TIA for any assistance!

Dave

[DDS]

OK, I did some homework and learned how the system works. Removed and cleaned the very clean flame sensor. I noticed that the pilot flame did not reach the sensor, though the ref. material I have says it should 'impinge' on the sensor by 1/4 to 1/2". the flame seems to spill out around the base of the pilot 'orifice' and not 'shoot our' toward the sensor the way I would imagine. Anyway, when the pilot fired, I gently blew on the flame, encouraging it toward the sensor (though it was not exactly impinging...) and the burner lit.
Its late and I can't remember if I actually tried the thing after cleaning butn without blowing on it so we'll see what happens. If the problem recurrs, I'll know it is a pilot problem. If not, the sensor was dirty. If that's the case, it doesn't take much dirt!
Thanks to those who might have helped!
Dave

[Troy]

Glad you solved your problem. Welcome to the forum!

[wisslerjoe]

Thank you for your information. I noticed that my fan was running but that the temp had dropped to 65 degrees in here. I have a problem in the past with the bottom panel of my York Diamond not making up with the button telling it that panel was in place. Normally just pushing on the panel does the trick. Didn't work this time. So after reading your post I found out I had the same problem. My ignitor worked, the gas would kick on but the flame would go out and the furnace would shut itself off. I took the sensor off that you mentioned and wiped it off with a rag. I was pretty dusty. Hooked it back up and now I have heat. Thank you for posting your problem and saving me a ton of money. I think I am going to go purchase a replacement sensor for the future in case cleaning it doesn't work next time. It gets cold here in Iowa this time of year. Thanks again for your help and for this forum.