Jeff Wisnia wrote:

Over the years I've had to replace maybe a half dozen thermal fuses
which appear to have failed without ever being heated beyond their rated
temperatures.

Most recently a small electric space heater used in our office under my
desk stopped working because its thermal fuse had opened. The fuse was a
MICROTEMP G4A0 121 degree C unit, and I'm pretty sure that nothing had
blocked air passage through the heater and caused its internal
temperature to rise enough to open the thermal fuss.

Jeff


After having the thermal fuse in our dishwasher fail several times, and then
an aftermarket part fail on the first time it was used, I bought some from
Digi-Key. Hmmmph, should have known better, DON'T solder it in without a
heat sink! The (2nd) new part seems to be working fine. Instead of $15
each for a nice piece in a plastic housing with 1/4" quick-connect
terminals, I can get a bare sensor/fuse for $1.50 from Digi-Key.

Jon