Interesting evening spent diagnosing heater blowing fuses

You should buy a furnace exhaust screen on Amazon for not much $ to keep all insects and varmints out of your furnace! I learned this from the customer reviews on Amazon when I bought our new TT last year with all the warnings that you need to get screens to cover your furnace, Fridge and water heater vents or be faced with what happened to you! They are not expensive and I got all 3 from Amazon and they are easily installed and work 100% to prevent the kind of damage you had!