Number 3 fuse continues to blow out every time I plug the furnace power I disconnected all thermostat lines to the board I even disconnected ac power fuse continues to blow out. So I replaced the transformer in the furnace fuse continues to blow out.help

Sounds like that furnace board is bad. Check this link:
Contact Us (http://www.brokenthermostat.com/Contact.html)
These guys will help... they helped me