Thermal fuses in appliances

[Cursitor Doom]

Hi all,

Well, I got my tumble dryer working again by just cleaning the nylon gears in the tumble/reverse timer with solvent; the grease on them had congealed and hardened and forced them out of mesh (they don't run in proper bearings). So fine in that regard. However, as some people warned me, the power to the heating elements is no longer there so it looks like one or more thermal cut-outs have tripped (presumably when the drum stopped turning owing to the earlier problem). So.... where can I find these cut-outs and what do they look like?

cheers,

cd.

[Calvin]

Have a look for a small (normally red) button high up at the back. That's where it was on mine.

[Andrew Gabriel]

They mostly look like a small cylindrical component, metal case with one lead connected to it, and opposite end is plastic insulator, beveled, with the opposide lead going into it. The metal case is live, so they're sometimes in a PTFE sleeve, but I doubt they would be in a tumble drier where the are live elements anyway and quick response is required.

When you find it, try reading the temperature value off it before doing anything which might rub the markins off.

The connection is usually crimped or reveted or spot welded, as soldering them is likely to trip them!

[Jeremy Nicoll - news posts]

Websites like:

will show pictures of many of the parts of particular models of appliance, which makes it a lot easier to find out roughly what they may look like. But beware different components which look similar...

[meow2222]

bottom of:

NT

[SteveW]

If yours is one like those at the very bottom, look carefully at the black body between the two metal tags and see if there is a hole. If there is, pushing something thin in (I've used the back end of a needle) will usually reset it.

SteveW

[Dave Liquorice]

The washer/condensing drier we had had the above as last ditch protection if the self reseting sort bolted to the heating element housing failed closed or just the interior of the machine got to hot. Ours tripped FSVO "just in time" as the caked on acummulated fluff around the heating elements was just starting to char...

Yep...

[Graham.]

They are supposed to be self resetting, but they often fail open circuit.

I would expect that type in a tumble dryer rather than the wire-ended ones mentioned earlier.

[Andrew Gabriel]

There is a manual reset version of them, with a tiny red reset button in the middle.

You may well find both types.

[Brian Gaff]

Well I'd have thought they would auto reset myself. I have one on a fan heater that once unplugged for about half an hour will reset itself. Brian

[dennis]

The one in my old washer dryer's dryer heater was a one shot. The idea was that if it went you probably needed to unclog the heater housing where the fuse was.

[F Murtz]

Are people talking at cross purposes here? Is the OP talking about thermal cutouts, which are probably klixon, or thermal fuses which don't reset once blown?

[Cursitor Doom]

There are two of these devices mounted above the heating element shroud; one had popped open circuit so I've drilled a tiny hole and reset it as instructed here elsewhere. The other one hadn't tripped, so they're now both closed circuit again according to my ohmeter. However, still no heat so it looks like there's something still lurking somewhere that needs attention. Any ideas?

[Cursitor Doom]

Scrub that. There was heat after all. I simply forgot the importance of re-fitting the cowling at the back so the heat simply wasn't going into the appliance. D'oh!

[Cursitor Doom]

This kind don't. Like I was told earlier up the thread, you have to drill a little hole in the centre and pop 'em out with a suitably thin drift.

[Windmill]

About 20 years ago I was very puzzled (for a few minutes) when a replacement non-resettable thermal fuse failed to fix the problem - after I had soldered it in! Duh!