Electronic ignition Furnace would try to ignite... "then go out". I removed the upper panel to inspect. The furnace will now ignite and run normally with panel removed--I put panel back in place--ignition fails.

Brand?

Exact model?

Panel Tag states the following--The Brand is Air-Ease, Ultra V, tech 80, 45647-001. Inside sticker has longer model # G1N80BU10014B-A

Spec sheet

http://www.airease.com/pdfs/jg1n80btur-100.pdf

Make sure your air intake is open if so equipped on that 80% unit.

Does the circuit board flash or blink a code when in the failure mode?
If so post the code(number of blinks) and the meaning. The legend for this will be on the back side of the blower motor access door.

A problem such as this is very difficult to fix on the net, Since it only does this when the door is installed I suggest you start by checking all wiring for tightness especially if you have the Honeywell smart valve sometimes called the dumb valve by folks in the trade. Your furnace is made for various manufactures including Armstrong and the problem with condensation dripping from the flue pipe on to the gas valve is well known. This inturn damages the electrical connections on top of the valve rendering it damaged. Hete is a posting by a company that sells replacement parts. It covers that quite well but there part prices are way to high in my opinion.

Check the wiring in the furnace.
Check the wiring and move it around a bit on the top of the gas valve.

Then post back with what you find.

Here is link to gas valve problem and I guess you have the Honeywell if you have this style of unit.

Armstrong, Honeywell Upgraded Smart Valve 1/2 in. NPT x 1/2 in. NPT Intermittent Hot Surface Pilot Ignition SmartValve™ Control with slow opening and 3.2 in. wc pressure regulator setting (3-Molex Plugs): Best Buy Heating and Air Conditioning (http://bestbuyheatingandairconditioning.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=GSV44673001&Category_Code=gv)

Thanks for the timely and helpful responses.

1st-No blinking LED code (only steady rd light)

2nd-I pulled off all panels and "wiggled and pushed" on all wire sonnectors from control panel to peripherial attachments.

3rd-I disconnected heat sensor (probe?) and reconnected it.

4th-I pulled out electronic air filters to clear path for air intake.

I replaced panels and the furnace IS igniting--Staying lit!?

I hope it stays running. Something had to be loose and when the door was put on it flexed.

Thanks for now... I hope the blower intake still draws and flames stay lit--after I re install the electronic filters--at least the filters are now cleaned.