Atwood Furnace 8531-IV-DCLP Only burns when igniter....

Just wanted to come back and say I’m happy That the forum has not lost quality contribution. Thank you all very much for your input. I went ahead and replaced both the board with a new dinosaur and also the igniter. The furnace works like new again. The advice here gave me confidence to go ahead and buy the parts instead of a full furnace replacement, which I could’ve easily done, but the parts were substantially cheaper of course. Many, many thanks.

Beware if you replace the whole thing that the new one fits. Apparently the "replacement" is a bit bigger and you have to do something or other (forget) to get it to match in back with the ducts (or something like that! :( ) Huge PITA.

You said you get a click for the igniter after the fan is on, so the sail switch works. If you get a click but no ignition, maybe not enough gas, but you said you got a brief burn, so there must be gas. So it is all about keeping the flame lit.

The sparkers are supposed to sense that, but you cleaned them. ISTR on other similar issues there is a "ceramic" thing that might screw that up (but that might nave been on a water heater or fridge?)

The board might be the problem, but if it lights and won't stay lit, it could be the electrode sparker thing at its end, and not the board.

Sorry for the lack of technical terms. It is what it is. (Ours is an 8531-II, so older, might be a little different.)

Do any of you folks know which Dinosaur board will work for this furnace by chance?

Thamks to all who responded to help me!!!

At this point I have removed and cleaned the burner (it had stink bugs inside it and slight surface rusting). I lightly wire wheeled it and the electrode tips. I also blew out the burn chamber real well.

Put it all back and still have exact same symptoms. I am thinking at this point to either replace the electrode assbly or get a new board, or both. A whole new furnace is about 500 on ebay so if the parts get up there I may just do that.

Our 8531 had problems like that and it turned out to be the burner thing--a big tongue shaped metal part with the sparkers out over the top of a screen and the gas comes out under the screen and the flame is there. On ours, the screen was all rusted out and this distorted where the flame was supposed to be so the sparkers were not getting a proper reading. I managed to find a replacement burner and all is good.

There are a couple of youtubes showing how to get at the burner. Hardest part is putting the screws way in there back in--you need a magnetic screwdriver. Also hard part is shoving the inlet gas tube out of the way so you can get the big piece out that has the burner stuff attached behind it.

Bad / dirty ground - clean
Bad / dirty flame sensor - I would change this before the board.
Bad or burnt propane chamber

Clean the flame sensor. Use a brass brush or place towels under it and spray with carburetor cleaner to disolve the carbon.

Great info.. thanks very much. Trying the connector right now. If that doesn't work Ill search for Dinosaur replacement with my model number.

The board is likely not sensing that the burner ignited. The igniter tip also acts as the flame sensor and may be out of position or dirty. The first thing I always try though, is to remover the wiring connector at the igniter board, and reinsert it a few times to clean the contacts. The flame sensor provides just a tiny voltage, so even a small amount of corrosion can interfere with it. Worst case, the board has failed, in which case I recommend getting a Dinosaur brand board to replace it.