Any help on this would be GREATLY appreciated.
First off I am a relative novice to home repairs in general and furnaces in particular. I bough my home 8 months ago and replaced the AC over the summer. The furnace (Lennox G14) worked fine last winter.
Now. A few weeks ago, the furnace stopped working. I read some post on here, and had to hit the control board a few times to get it to start. It got worse and worse where I was having to do this 4 times a day. A tech guy came out, and wanted $XXX to replace the control board. He couldn't figure out anything else was wrong.
Instead, I purchased a control board from this site for $XXX, and the unit worked fine after for a few days. In fact, it had worked fine for a few days with the old control board after the guy had also cleaned the unit a little and put in a new flapper (is that right?, circular 3" paper like thing in the main chanber).
This morning the furnace was out again after being good for almost 5 days. Now the issue is different though. Now the light is OFF when I come downstairs to look at it. I flip the switch to turn it off and on.
What happens is it comes on (low rumbling noise). Then it tries to start a couple times with no luck. Then it starts for a few seconds and dies off again. It does this for a few minutes. Then finally it will come back on again.
Once, after the tech guy left, it did the same thing and the error light on the control board read "Low flame sense". It doesnt do that any more though.
Here is what I am thinking:
1. The tech guy had checked the gas and made a small adjustment with a screw driver ... could it be it's not getting enough gas now??
2. When I replaced the control board, I did not replace the red sensor cable that came with the unit. Should I have done that?
3. Could it be the spark plug?
Any and ALL ideas would be helpful. I already put $XXX into this and don't want to spend too much more. I might just replace it otherwise.