Lennox G12 Pilot ok but no burner

[Dingo]

Hello everyone,
I bought my house a year ago and the furnace worked great all year last winter. Now, all of a sudden, it needs a tap on the left hand side of the "Johnson Control" (ignition control) to get the burners to fire up. The pilot always comes on whenever the Tstat is below room temp. I just don't get the "click, click, whoomf" that it used to do after lighting the pilot. I do have 24VAC coming from the transformer and up to the ignition control....it seems to me that it's a sticky gas valve or dirty relays inside the ignition control. Which is more likely? Or am I way off mark? It's requring harder and harder taps, and this doesn't make me feel good to be taking a hammer to my furnace. Originally this started a month ago, got it working with a light tap, and it worked fine for 1 week. Another tap and it was fine for another week, and now it's every time the furnace needs to fire up that I have to give it a whack. What's up? Thanks in advance for the help.

[Joel]

I had this problem and thought it was a sticky gas valve though it got worse and worse replaedthe gas valve and discovered it was the board though when changing the board found a loose ground first chech your grounds are tight on the furnace and the one entering the board if ok probably your board

[Dingo]

That was what I had tried originally, and that got it working for about 2 weeks. Maybe I should give it a good thorough clean and re-check all the wires. Could it be the relays on the board are just all gunked up? And did you have any trouble replacing the gas valve or board? I'm a pretty good do-it-yourselfer, confident, but some of the people I've talked to advise against doing gas work yourself. Did anyone have major problems? Thanks very much.

[fixit]

So can you solder??
1. the connections can go bad on the safety,TURN OFF THE ELECTRICITY TO THE FURNANCE
2. REMOVE THE SAFETY ]SCREWS] PULL THE COVER OFF THE TOP
3. bend tabs holding the printed circuit board.
4. solder the bad connectins.
5. If this is beyond your skill or comfort level CALL A PRO
6. The controls are like $60 as I recall