model dgat070bdd please help

[straydog]

I have been fighting this furnace all winter, the problem started a couple years ago, when there was a cold night (below zero) the furnace would start the flame would shut down the blower fan would start and after a few minutes it would start again and run just fine. this winter it started doing the same thing but it did not need to be cold and it would keep shutting the flame off till it gave up and started flashing lights. it flashed 4 lights(limiter switch) so i found a bad switch and fixed it, it worked great for about a week and started doing the same thing so then I found the chiney pipe was rusted threw and there was probobley exsast gas getting in the flu so I fixed that. It worked for about a week and started doing it again but the trouble light would flash all kinds of differant things so I ordered a control board off this site and replaced it. it worked for about another week and now it is doing the same thing again only the light flashes once which is failier to light. The flame starts burning and then it kicks in the blower at the same time as the flame shuts off. Ive cleaned the flame sensor, please help.

[Robert]

Hi,

Inspect main burner orifice for spider-web-eggs blockage. Could be a bad remote flame sensor, bad gas valve.

Incorrect gas pressure, orifices (if it has never worked right). Would just have to slowly troubleshoot the entire circuit, piece by piece until problem found.


Thanks,
Robert