I am having a problem with my Armstrong Ultra SX90 burners shutting down. The Pilot will light, the burners will ignite, then they shut down ... sometimes immediately, sometimes later. Most of the time, I can turn the switch OFF on my Honeywell valve and then turn it back ON and the burners will light again ... for a while. I have checked the vacuum lines and there does not appear to be any water in the lines or blockages anywhere in the system. I even checked the exhaust line and it is obstruction-free. When I changed my Ignitor / Flame Sensor Assembly, the furnace actually ran flawlessly for a day, then resumed acting up again. However, it seems like anytime I shut the unit down at the breaker for a few hours, the unit will act better for a while. When the burners go out, the Roll Out Switch & Pressure Switch are still closed - I checked with my voltmeter. I am not sure what to check next. I suspect that I might have a bad control board, maybe with a flaky component that starts failing once it's been powered for a while. How do I diagnose? What do I do next?

Here's the situation: I have a coleman DGAA furnace in a 1971 mobile home. The mobile home was built in 1971 and we are located in Massillon, Ohio. We are experiencing okay weather right now but tonight it is supposed to drop to 32 degrees. For two weeks now I've been through hell and back trying to get someone from an HVAC company to come out and repair my furnace. Apparently nobody wants my business because nobody has returned my calls or responded and the one company that was supposed to return did come back today a week after the diagnosed the problem. ACCORDING to them the problem is the gas valve is not working. However, they cam in to replace it only to find out that the gas valve that IS on there was welded on. Well the company that came out today to fix it is the same company that put the damn thing in to begin with. When I bought this mobile home the furnace was installed already.:wall: Anyway when I first turned the heat on over here back in January I got 3 flashes from the circuit board so I bought a new pressure switch. I replaced the pressure switch and cleaned out the tubes. Well I still got 3 flashes regardless of which pressure switch was in the thing. So I called my friend who does HVAC repairs and he said to buy a new circuit board. I bought a new circuit board, turned everything on and got 1 steady flash. Well I thought it was the hot surface ignitor and so I bought one. Big mistake because according to the HVAC guy that I called from the company that installed the furnace....the ignitor is fine if the glow coil is glowing. When I turn the furnace on and put the thermostat on it goes through its checks, the inducer comes on, it does some more checks, the glow coil glows, does some more checks, it all shuts off and starts over again. Sometimes it bypasses and blows cold air through instead of hot. I have the thermostat set for heat at 80 degrees but it still just blows cold air. The sensor was cleaned and there's no dust in the furnace or around it at all, in fact the HVAC guy came and cleaned the furnace to be sure. I haven't reconnected anything, the gas valve is still disconnected and I am almost tempted to go in and reconnect everything to see what happens. I have 2 small children one is only a toddler the other is a newborn. I won't let my kids be cold even if I have to sacrifice everything but it still sucks being cold, myself and we could really use the heater tonight. Here are some pictures[IMG]https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash3/529833_277330309015084_100002143510600_639826_1498424490_n.jpg[/IMG] [IMG]https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-prn1/529833_277330292348419_100002143510600_639824_1168746551_n.jpg[/IMG] [IMG]https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash3/529833_277330302348418_100002143510600_639825_1217814749_n.jpg[/IMG] If you need more information or pictures I am happy to supply everything asap. Thanks for any help! :wall: