I'm proposing then, that for the current poster, and the
ones that are surely to follow, that it might be worth
suggesting giving it a bit of a push with something to be
sure that the contacts aren't welded shut.
okay, that's a good point so I did that, Ken. It opened without any
discernable sticking. But, I notice this: current goes through the thermal
fuse, then splits in two. Part goes directly to the shorter run of heating
coils, and part goes to the bimetal component then on to the longer run of
coils . (The dryer has two switches and therefore four settings for temp.) So,
the bimetal can interrupt the longer series of coils, but not the shorter
series. The fuse cuts power to both.
I'd been thinking that the bimetal might open when the current running through
it gets too high, like a regular fuse. No? And conversely the thermal fuse
melts and opens from ambient, rather than internally generated, heat. That
doesn't explain what happened in the boot, though - unless the bimetal opened
and reduced heat, but the dryer was still chugging away on low heat until the
fuse melted. I don't remember, it wasn't recent.
I also can't figure why the fuse didn't melt until the dryer was turned off -
unless the coils were still radiating heat long enough after the airflow
ceased to take it away - as Jim and/or James seemed to be saying.
Also, I notice there is no soldering whatsoever anywhere that's in the tube
where the hot air flows through - as if the hot air might melt any solder
there. That's a surprise.
I uncrimped the fuse. There is no writing on it that I can see - so I'll go
with the lowest fuse I can get, as recommended.