Stove Repair... or not

[cjsmith]

Earlier I mentioned that the stove doesn't work. This evening we took it apart.

Interior Wiring

We took out the burners and tested as much as we could with a multimeter. Our major finding was that the previous owners used this thing as a grill A LOT and never ever opened it to clean. I used this opportunity to scrub the bejesus out of a lot of it.

Anyway, the problem we've seen is this: when any of the burner controls are turned on, the "caution, it's hot" light will illuminate and that's it. The burners stay cold. We determined that the modules themselves were fine - they are of a very simple design, too, so we could quickly tell they were fine.

Next we found how to take the control unit facing off. Wow, that's a lot of wires... and a heck of a lot of grease. Sadly, the complexity has so far defeated us. We're trying to figure out, given a multimeter and a broken stove, how the thing should once have worked. There are no wiring diagrams available on the net. The stove manual, which of course we still have, is not very detailed and says only to install the stove "in accordance with local codes".

We got as far as trying to remove the top facing before we realized that was probably the only thing holding the guts of the stove up, so we sheepishly put a whole bunch of screws back in.

More on this later, I hope.

Comments

[tmc4242.livejournal.com]

Ah. Read earlier post again.

Check under the counter for a large wall plug. It might be direct wired, but an oven style plug would make sense.

Measure voltage from the angled holes to the more rounded hole. Or to the center one if there is no ground ( ie rounded hole ). You may have lost half of a breaker. The indicator light might work with only half the voltage present, but neither burner will.

[cjsmith.livejournal.com]

Skimmed your first comment & will go back to it.

*nod* Yeah, we looked at the connection to house power first. Sadly, it is indeed direct wired.

Half of a breaker? How would one "lose" half of a breaker?

I'm curious: if half the voltage is present, wouldn't the burner get somewhat warm? After all, those high-to-low-temperature control knobs are just big potentiometers.

[cjsmith.livejournal.com]

After all, those high-to-low-temperature control knobs are just big potentiometers.

Heh, heh. That's what I get for making assumptions.

[tmc4242.livejournal.com]

:-)

[tmc4242.livejournal.com]

The "burners" work on 240 VAC. If one side of the breaker has failed, the there will be no return path, so no current will flow.

The 240 VAC breakers have 2 sets of contacts, one for each "leg" of the power coming in. Since the burners use no neutral, if one set of breaker contacts has quit working, you'll see no heat. ( For reference - houses are wired across a 240 VAC center tapped transformer. The neutrals go to the center tap. )

If you check diagram on the catalog page I pointed to in my first post you'll see that the controls are not just pots. They're little thermostat sort of things. Rather clever - and thanks for posting this problem BTW - I learned something new too.

This arrangement makes sense if you consider that in order to do the trick with a pot, the pot would have to dissipate all the energy not sent to the burner when the heat is set to anything but "full". Lots of waste heat that way - at the knob. A bit of a hazard to the cook. The on-off method only sends what's needed. I'm guessing the cycle time must be pretty short for the range top versions. I've never noticed one cycling.

[cjsmith.livejournal.com]

This arrangement makes sense if you consider that in order to do the trick with a pot, the pot would have to dissipate all the energy not sent to the burner when the heat is set to anything but "full". Lots of waste heat that way - at the knob.

Good point.

I've never noticed one cycling either, so I too would guess the cycle time is pretty short. This is interesting! I've never thought much about how stoves worked.