I am getting and error code 33 on our furnace. We checked all the filters and while they were dirty they were not overly dirty. The error code is NOT changing to a code 13 like it says it will. Also, the fan is running constantly even though the t-stat is on auto and the unit doesn't fire up. As soon as we switch on the unit, the fan comes on. We hit the resets but no change. When we turn it back on the unit doesn't fire at all.

Any ideas? We are in the middle of a blizzard and can't get anyone out here until later. It is currently 58 in the house! Help!

Cay22, Did you fix your problem? I have the same thing right now going on with my Carrier furnace. Any help would be appreciated.

It might be that your furnace is interlocked with your exhaust fans.
Try holding the reset button down longer, switch the breaker on and off.
Call an HVAC mechanic