Yeah, it's me again. Seems like forever that I have been at this. I just end up finding a work around, like window AC units, portable heaters, etc.
Anyway, right now, I'm getting the "no call for heat" code, slow blinking red light. The problem is, the W connection on the circuit board is throwing sparks and blows the fuse whenever a "call for heat" is initiated. I read elsewhere to try a jumper wire on the control board from the "R" to the "W" and it's throwing sparks until the fuse blows still when I do that. Then, I hooked up another control board that I have (not sure if it works or not), but it does the same thing.
Another test I did (on accident) was touch the "W" (call for heat) wire to the "Y" spot on the control board (this spot calls for the AC to run) and the furnace runs like when you turn the thermostat to the "ON" position (from AUTO). It just blows air out, neither hot nor cold. Neither the AC not the flame kick on.
So something is causing the "W" to spark. Wondering if a wire was plugged into the wrong spot on the control board? One of the last things I did was change the transformer. Could plugging wires to it wrong cause this? Thanks to all who have helped me out up to here and in the future. Kind of fun trying to figure this out anyway, eh? LOL