I worked on the furnace from hell today! The burner was lighting on a call for heat from the thermostat, but only staying on for a second or two and every maybe third or fourth trial the flame would roll out from the burner, so I removed the flamerod and cleaned it with sandcloth and reinstalled it. Same problem! I noticed when the flame came on the flamerod didn't look like it was in line with the flame, so I went to the Lennox dealer for answers. They sold me a replacement kit(62K50) that is supposed to put the flamerod in the proper position. Well I installed the new part but the problem is the same.So I figured it had to be the ignition board(65K07) but that also didn't help! Installed a new gas valve didn't help! Changed the hose on the air proving switch! Changed the air proving switch with a used one which brought on the burner a lot longer than previously but still cutting the burner out. Also with the burner on, if I take off the chimney cleanout cap the burner goes out and when I put the cap back on it fires up again.I'm not sure what else to chage to make this furnace run properly.