The third burner on my American Standard freedom 80 two stage furnace won't light?

Flow to the gas valve is 6.7wc. This is a freedom 80 two stage furnace. Could it be I'm not getting enough pressure to the manifold for the third burner to light? Is there a way to increase the pressure at the valve? If yes could you please explain the adjustment I need to make? If gas pressure isn't the problem. What else could it be? Thank you!|||the old timer actually had a true answer, a spider web can cause this but before starting out on a possible wild goose chase you should pull the burners out and clean the ends. I work on a sh!t ton of A. Standard units and I can tell you that if you have LP gas the burners definitely need cleaned. You'll need a 5/16 nut driver to remove the top holding plate that rests across the burners, when taking it out be careful with the ignitor if its attached to it, and the burners simply pop right out one at a time, use a wire brush on the ends, usually their will be some crap plugged carry over chanels or what looks like the small slots on the ends of the burners, clean those out with a tiny rod, perhaps a paper clip or something of that size.





6.7 " wc incoming is good for natural gas but low for LP, outlest pressure for N. gas = 3.5, LP close to 11, you may only see something around 9 or 10, thats still alright and not the problem.|||The orifice may be restricted. With the unit off use a bent paper clip to clear it.


The orifice should be where the air venturi of the burner connects to the manifold. Don't adjust the pressure, that's not the problem.|||rust in the chamber, or a spider web in side


,[believe it or not it will stop gas from flowing]