concord 80 plus furnace, pressure switch issue
 

I have a concord model cg80ua075d12a-1 furnace that just stopped working, it is about 4 yrs old and has been great till now... It has a flashing light that blinks 3 times and according to the panel it says the error is Pressure switch open, should be closed... Please help me figure this out, its cold in ohio here these days... almost record cold!!!!

That could be from several diferent causes. Plugged chimney CO poising potential, Draft induser may not be running. The pressure switch hose could have water in it. or the port the pressure switch hose connects to could have debri in it. The last 2 are the most common or easyest for the home owner to check.

1 last thing could be a bad psi switch

Where do I look to check it?? There is a humidifier attach to it... could that cause the issue??? was running great till tonight....

I assume that the Draft induser is the smaller blower that appears to go to the chimney... it clicks to try and come on but does not... it does not spin freely at all... can this be my issue???
Update - Being the intuitive person I am, I figured out where the pressure switch, the line to it, and the draft induser were... Safety precaution were used, turn breaker off to the furnace and turn switch off... and used common sense.. as stated above, the draft induser fan did not spin freely... I figured out how to remove it to see if it was a bearing or maybe a fan that got bent stuck or otherwise... and to my surprise, I found what was left of a starling in the end of the draft induser... I just removed it, and am putting it back together now to see if it worked... I'll post when done....
Update 2 - Unlike the bird I removed, my furnace is now working properly... the kids are warm, the wife is happy and I am the hero.... for tonight... But I could never have fixed it without your help... thank you ever so much... I took a picture of it before I removed the bird... I posted it to my album.... I will inspect the chimney tomorrow and ensure that there is no way another Firebird can come in...