I went on this furnace 2 times today. Arrived both times to lockout and no diagnostic lights on the board. I reset power and the furnace fires up and runs ok. Homeowner tells me ignitor comes on and gas valve comes on but does not ignite burner. I checked output gas pressure 3.5in wc. burners are clean, and placement of ignitor is positioned correctly. I just wanted to know if their could be something in the manifold as far as debris that might cause the failed ignition.I was told that the gas valve and board were replaced last year. I am going to take the gas line and manifold off and look for any debris. I was just wondering if anyone has had a similar problem to this. Thanks