I have a pressure switch error on my Tran furnance- this is causing no call for heat. I replaced the pressure switch and that seemed to work for a couple of days, now its not calling for heat and Im getting the same error. I've cleaned out the drain hose and made sure there are no obstructions. What else could be causing this problem??

Check your vent to be sure it is free of any obstructions, also make sure your combustion air inlets to your closet are open and not pluged with something, good luck, Mike