I have a 12 year old Goodman GMPN060-3 furnace. Occasionally it will not light the burners. Three technicians have come out to inspect it. The first person said it was the drain in the floor was plugged. He blew it out and the furnace worked for 2 weeks. Next tech came out and found the switch above the middle burner had tripped. Reset it and fine for 2 weeks. Third time the same switch had tripped. Switch is on order now. All 3 techs say that when the burners ignite, the flames are coming too far towards the access door. None of them can tell me why this is happening. There is central air installed in the furnace as well.

At the times its not lighting,, has you checked the circuit board for a blinking light (code),1 blink,, stop,, 2 blinks, stop, 3 blinks stop,, or what ever it might be,, if so look on the inside of the door and see what the code is,, did anyone check the gas pressure at the gas valve? Or

I have not checked for codes yet. Just found where the light was last night and will need to wait until it stops working again. As far as the gas pressure, I have not been here when they come but my wife says that the first tech did and it was OK

The switch above the burners? With purple wires? If so, that is a flame roll-out switch. If it is tripping, the area around it is overheating. This is usually the result of a leaky heat exchanger causing the burner flames to drift off target (hence the name flame roll-out). Try this: Observe operation from start-up. If the flames appear to be disturbed when the blower starts, you likely have a faulty primary heat exchanger.

Watched the flame while the blower started and it did not change. It is like there is a slight build up of gas when the igniter fires and a flash of flame backwards then everything runs fine.

You have delayed ignition. Check for proper gas pressure and that the pressure matches the label on the furnace tag. Check to make sure all burner orfices are clean and if the burners are equipped with flame jumpers that they are clean.

Finally an update to my problem. After weeks of waiting to get the flame roll out switch replaced the tech showed up with the proper one. A couple of days earlier it had tripped and when my wife went to reset it it was hot although the furnace had been off for a while. The tech went to replace the switch and found it to be hot. After some further testing he found that the circuit board was faulty. Both the sensor and board have been replaced and hopefully after we return from a weekend away the furnace is still working.

Glad you got it fixed. I hope it holds up for you.