Bill,
Get ready to get confused. The motor on your heater pulls about 6 amps I think. So if you put a fuse in the circuit, you would use a 15 amp fuse. This would cover the fan motor for 150% and protect wire as small as 16 gauge.
You say you are going to install a fusible, and not a fuse (??) so the same would apply. If you go techno-nuts, you will see that the ampacity of the fusible link is tied to the wire size, not the device being protected. To get net, pick any size the equates to 150% of the full motor current...6 amps X 150%= 9 amps. The closest fusible link is the 16 gauge @ 15 amps. That would be your choice....why not a good old fuse?
Stuart
