What type of cooktop do you have? How long is it on before it shuts itself off? Is you pan completely flat on the bottom or is it warped a bit? Does you pan warp as it heats (leaving only a small area actually touching the cooktop)? My cooktop has overheated once, after hours of canning - it gave me an error code when it did. If the cooktop is doing exactly what it does when it can't detect a pan, then maybe it just can't detect the pan (warping).

Sheesh - a couple of the "you"s should be "your". Apparently I can't type today.

It's a 30" (but takes up 36") Kenmore, circa 1984. No error codes on this model! Just a beep. It takes around 7 minutes for an empty pan and much longer for a full one (more difficult to measure as I don't actually cook food on high for long periods).

The two pans I've had issues with seem to stay pretty flat, and after the "burner" stops functioning I can move them to a different spot and continue cooking (but can't get the big burner to restart). I need to test it and see if I can stick a different pan on there once it stops working but of course I'm usually too busy to experiment when it happens. Next time perhaps I'll remember!

I do have an old very warped pan I used when I first moved in and was stuck with induction--it didn't have any problems. Well, it did in that the half of the pan in contact with the stove got much warmer and I couldn't really cook well on it, but the cooktop never complained. No problem with detection, and this pan is WARPED.

Couple more questions. Is this happing on only one element? Is there a fan that comes on when you start an element? Does it come on for all elements? Is this a new problem? Does it do the same thing if you have the cabinet doors open?

I believe it only happens on one element, the "PowerPlus" one. But that may be because that's the one I use for high heat. I can't tell if there's a fan--if there is, it's quiet and indistinguishable from the mild hum of the unit functioning.

I haven't lived with this classic long enough to know if it's a recent development. I haven't tried cooking with the doors open because, well, galley kitchen, clumsy spouse, you know...it also isn't predictable enough for me to know if it's doing anything.

It's not a HUGE problem. Just...weird.

I have a new kenmore I guess about 18 months old now. It seems to shut itself down sometimes when in heavy use. Mostly when using cast iron on high heat. It starts beeping and flashing a error code.
I suspect it is a heat issue or a problem with the fact that I have only 30Amp service to it, but it does not blow the 30A breaker.

My cooktek will shut down adn displays an error code if it overheats. For example, I needed a bunch of boiling water once for a non-kitchen job. After two largish stock pots of water were boiled, the unit shut down part-way through the third. The air in the cabinet was quite warm.

The good news is that it seems to recover completley after cooling down.

Had that Kemore unit also...would shut down in protective mode on occasion. I still have it if anyone wants parts.

I now have a CookTek, which will shut down if the voltage is not correct.

Thanks all. I guess it must be the heat. But perhaps I should look into what sort of electrical service it's getting, just for fun. At some settings, it makes the whole house's electrical pulsate. Can't be good.

And glennsfc, you replaced that thing with another induction? Did it break? Do newer models work better? I think it's a pretty great cooktop, for not being gas...:)

I loved my old Kenmore induction unit. But, I fried the microcomputer circuit board and just decided not to fix it. You can still get the part (not through Sears), but it is not OEM.

The seal between the touch controls and the glass top can degrade over time and allow spilled liquids to seep underneath and drop onto the circuit board. Just wipe up liquid spills right away and your little "induction cooktop that could" will keep on cooking away!

The newer stuff is probably just as good, if not better than the old Kenmore unit, although I don't think many of the newer units are made in Japan. My old Kenmore was made in Japan by Sanyo. It was a great and wonderful cooking device and is missed. Of course it had no where the power of the CookTek that replaced it.

So I shouldn't just slop a bunch of soapy water all over and let it sit before I wipe it up? Good to know. :)

They'll all shut down if they get too hot. This is why ventilation is critical. There has to be enough space around the unit inside the cabinet for air to flow.

Secondly, I believe the newer units act differently from the units of over 20 yrs ago. The pulsing of the old units was much slower and therefore noticable whereas today the pulsing is very fast. Which now sounds like a 'ticking' or 'clicking', or at higher power a 'whine'.

And if your lights are dimming, it's because the service is too small. It is trying to pull more current than the circuit is set for and is dropping the house voltage as a result. The CB doesn't trip because the unit is pulsing and not pulling a steady overload current. That is, a 30-amp breaker doesn't 'break' at 31 amps. It requires an over-amperage for a certian amount of time before tripping.

One of the owner's manuals - might have been Kitchen Aid - suggests that it is a good idea to swap every few hours from one position getting a lot of heavy use (an all day canning session at high power for example?) if you have a similar position not being used much. Suppose the idea is to keep all positions ready for use rather than have one of them declare a cool down break and shut off.

How much air clearance is necessary for most induction cooktops? The thickness of the unit is pretty clear in the instruction manuals, but it's had to find how much open space you have to leave underneath...

Look in the installation guides.

Some of them are hard to figure out, but the info is there. And it varies between manufacturors. I've seen as little as 2" and as much as 8", with additional requirements for front and rear.

Oddly, the installation instructions for the new GE Monogram seem to require TWELVE inches, which is a deal killer for me. Seems extreme to me compared to other brands.