My furnace is intermittently not starting. It is an Amana with a White Rodgers 50A50-288 module in it. The error code I'm getting is "one flash." It says this is "Lockout - check furnace." Yep, furnace is still there... what am I SPECIFICALLY to check? Any suggestions?

Take the front door off and reset the furnace. Tell us what happens? Does vent motor run? Does the ignitor glow? Does the blower motor run?

I hear the thermostat's relay 'click', the furnace vent fan comes on for about 30sec. I hear what sounds like the burner start, but then quit, right away... after about another 30sec, it will try to fire again... until it fails and error code (one flash). It sounds like it is firing, but then it shuts down right away.

Flame sensor? I thought flame sensor had it's own error code, though.? Doesn't seem to be an ignitor, since it seems to fire up.

This is intermittent. Seems to eventually reset itself, even if it has to wait through (two or more?) auto resets (at night when I'm in bed and don't want to get up to reset it). Mostly works when I reset it by cycling the thermostat off /on, but sometimes fails then, too.

Yes if the flame fires for 5 seconds or less odds are it is the flame sensor

... guess I answered my own question... I just found the flame sensor, took it out and cleaned it with a piece of emmery cloth... put it back together and it works...

We'll see if the intermittent problem returns. I'll pick-up a new one, if it starts happening, again. If that don't work... I'll be back on here.

Thanks for the help!

Just read my last post...

Sounds like I'm being sarcastic, but I'm not!

Thank you Joshdta for your reply! I did come to the same conclusion, prior to reading your post, but if I hadn't, you would have sent me in a logical direction. People like you are helping other people save money and agrevation (or trying to). Keep up the good work! I'll try to help where I can, though I'm not online, very much.

Thank you!

How dose the flamesensor look

I have the same model 50A50-288, but both heat and a/c doesn't work now.
3 day ago heating was working fine.
Now I found the fuse is fused in the T.Stat, changed it.
It got fused again but both didn't work.

Any clue??
Please