another shameless plug for RV type and Furnace type like Dan said.
a possible solution to your problem which is an electrical issue - sounds like you have a (+) Positive wire touching (-) ground causing the fuse to blow
if you can pull the furnace out and look at the wires I bet one of the wires is maybe melted together or check your wires at the thermostat and see if you have any wires touching together.
if neither of those work then you will need to try and trace out the wires but my guess is that one of the wires is shorting to ground causing it to blow the fuse.
2011 Rockwood Mini Lite 2306 - Matt
2004 Dodge Ram 1500 Qaud Cab 4x4 with 35" tires and 3.92 gears, Dynatech Longtube Headers & Fabtech 6" lift + Superchips with shift Tuning
Nights Camped 2011 (37) - 2012 (16)-2013 (2) -2014 (5) -2015(0)
USMC 91 - 95 - F/A-18 Aviation Ordnance