@Art,

Try a pop fuse or pop breaker, 3 amp for furnaces. That way, if it blows, all you do is press the plunger button on the pop fuse. I have the same problem so I used two long wires on the pop fuse so that it’s outside of the furnace and can be reached easily. Most furnaces use 3 amp fuses . You can try a higher amperage also, but don’t go too high or you may burn the transformer or something even more costly. You can also purchase a transformer with a built in circuit breaker.
You may also have something shorting out in the thermostat or in the electrical
circuit.

Cheers mate!