mekanic

I have a Lennox Pulse furnace model G14Q3-60. The manual indicates there is a specified distance (clearance) between the tow plates of the Air Flapper Valve, but I cannot find that specification anywhere. Any help would be appreciated, thanks.

paul52446m

Are you having a problem with the furnace? As i recall if you have a flapper valve for the 60,000 then it will have the right gap. I don't think it is adjustable.
Later Paul

mekanic

The furnace was sputtering upon startup and eventually would ignite and run properley. The furnace company removed the air flapper valve, replaced the new flapper material, and the furnace worked IOK for a while then started sputtering and startup again! I decided to check it myself and found that three of the screws holding the air flapper valve to the furnace were loose, when I removed the air flapper valve assembly, I found that the center screw had been left too loose giving the flapper too much clearance! So i cleaned it, snugged the center screw up to the thickness of the spacer washer (which I think gives the proper clearance for the flapper, and reinstalled it properly. I also removed the spark plug, cleaned and regapped it to the specified gap, reinstalled every thing and the furnace now works like it did when it was new!
It works great now, and thanks for your assistance.

paul52446m

You did it right, when you tighten the screws up you have the right gap. Both the gas and air flapper valves should be taken apart and cleaned every year.
later paul

John11

Hi Mekanic,

It would seem to me that I'am having a simular problem with my Lennox Pulse, that is sputtering upon start-up. I had a technician out a few months ago to check it out and the advice was to try to replace spark plug but he was unwilling to do so as he suggested that there was a good chance it would break at which point I would need a new furnance. He suggested to just let it go and when it breaks replace the furance. Not sure how good this advice is, do you have any advice or do you know anyone who could service at a reasonable cost in the GTA location?

paul52446m

I don't remember what proves fire, does your book say there is a flame rod in that unit? On a call for heat the inducer comes on and purges and gas out of the fire pot and puts air in the fire pot. Then spark plug is energized and then the gas valve opens and the first load of gas enters the fire pot. The only explodes the first load of gas, after that the spark plug turns off. Did you service man clean or replace the air flutter valve and the gas flutter valve?. Did he clean the air intake screen in the intake box.
If there is a flame rod in there it should be taken out and cleaned with some fine sand paper. Check some of these things and let me know.
Changing the spark plug is not different than in a car. I have not worked on a pluse furnace in 15 years when i stopped selling them. but i don't recall having a problem with changing the plug