I broke my oven (AKA "sigh.. now what?")

[dragoncar]

I know this isn't a repair forum, but I've found the people here have a ton of knowledge and it ups my post count so I figure I'll give it a shot here.

I was broiling some stuff last night on my electric oven, using oft-heard advice to open the door a crack to prevent the heat sensor from shutting off the element.

This morning, the oven will not work:

It has three heating elements: bake (lower), broil (upper), and convention (behind fan).
The heating elements appear in good condition (not obviously broken)
None of these elements will heat on any setting (bake, broil, convection bake, convection, self-clean -- I tried them all).
I believe the control board is fine as I can enter any of these modes, timers, etc. without problem.  There is a little indicator "on" that indicates the heating element should be on.  This comes on and off appropriately.
I also think I can hear a solenoid of some kind going off during a call for heat.

So what's the deal?  My only guess right now is a "thermal fuse" triggered from heat rising out of the open door.  Supposedly I'd have to replace the fuse, but I don't have a schematic for this.

On the other hand, this oven has a self-clean feature which would result in much higher temperatures than I was using last night.  Which makes me think it's not a thermal fuse.  Are there other types of fuses in ovens (e.g. overcurrent)

Before I start taking the whole thing apart, does anyone have any suggestions?  Obviously, I just decided not to renew my home warranty ("free" with home purchase) so that's not an option.  It's a pretty fancy schmancy model, but older.

Any advice welcome.

[zolotiyeruki]

Having just barely repaired my own oven, I can give a *little* perspective.  In my case, the problem was the reverse--the broil heating element got stuck *on*, and nothing we did would shut it off until I went down and flipped the breaker. :eek:

It's possible that your situation is similar to mine--a failed relay.  How many "click"s do you hear when you turn on the heat?  You should hear two, one clearly after the other.  On your oven control board, often there are two relays in series that both must turn on in order to deliver power to the heating element.  One coil is turned on without any load (this is the safety one), and then the regular relay is turned on.  If the safety relay won't turn on, then you won't get any power to your heating coils.

The fix might be a simple as pulling the control panel off, giving each relay a sharp rap with the handle of a screwdriver, and trying again.  But your best bet, unless you're an EE with a lot of free time, is probably to pull the control board, purchase a replacement, and install the new one.

(Incidentally, this is the third time I've repaired this oven.  The first time was for some failed component on the control board, the second was for the main wires coming loose(!) from the bus bar, and the third time I replaced the relays on the board)

[FIRE me]

Try Googling the make and model of your oven / stove, plus “oven won't work”, “oven won't start” or similar. You might get lucky and get some very specific information on the cause of the problem and how to fix it.

[KarefulKactus15]

I agree with the above poster, google your model.  Also if you want some real step by step help, find the schematic for your model. Make sure its the correct one.   Myself, and Im sure many other people on this forum can read them, and tell you what reading you should get on a Digital Multi Meter (Harbor freight has one for5$).    If you find the schematic and take the correct readings I would dare say there is a 100% chance that you will easily be able to find the problem.

[Tetsuya Hondo]

Yes, Google it! My oven went kaput and thanks to the online DIY forums was able to correctly diagnose the issue as a bad control unit. It turned out that replacing it was incredibly easy and relatively inexpensive (~$100 for the part). I felt incredibly empowered afterward.

[dragoncar]

Lol, do you think I'm some kinda newb?  Nobody has info on my model.  I did find some good videos on replacing the thermal fuse on other models so hopefully it's similar.  Not looking forward to pulling this thing out of the cabinet.

I might email the manufacturer if I run into trouble.

Thanks!

[dragoncar]

Ok, I found the "limit switch" on top of my oven and the reset button wouldn't go in.  It looks like it has continuity, but one of the terminals is jiggly.  I watched it when I turned my oven on and the jiggly terminal started glowing red hot.  Flipped the breaker and pulled the switch, looks like old bakelite is disintegrating.  Seems like I'm lucky it didn't catch on fire.  I think the thermal disc is still operable, the terminal is just gone.  Found the part online -- I can get a new one for $22 or a "used" one off ebay for $12.  Gave the ebay guy a "best offer" of $11 :-P Yeah, I know I shouldn't skimp on a safety part, but I have no reason to believe a "new" one is any higher quality (except that my old one was disintegrating).

Apparently my oven can't do open-door broil because it's designed to suck cool air through the door to cool the electronics and cabinet.  Oops.

[arebelspy]

Lol, do you think I'm some kinda newb?

[dragoncar]

Lol, do you think I'm some kinda newb?

rekt

[dragoncar]

OK, replacing the "high limit switch" AKA thermal fuse worked.  The fuse didn't actually trigger (it's re-settable), it looks like one of the contacts failed over time.  It seems crazy that there's like 30 amps running across that tiny wire over those tiny contacts (going by my double breaker, not sure of actual amperage).  If I recall correctly, the ebay guy was asking $12.50 and I best offered him $11.50 and he countered with $12.00.  Saved a whole $0.50... score.  Opening offer should have been lower!

Also yesterday I fixed my refrigerator water dispenser.  The plastic tubing had broken months ago and I ordered the parts but was too lazy to get back there again and fix it.  It should have been a 2 minute job back there, but I actually am a newb with plumbing so I broke the quick connector to the water relay.  For some reason I thought I was supposed to pop the top off the QC, and then I pulled the tubing out until it mangled the metal biter thingy.  I didn't have a spare relay!  I then spent 15-30 minutes trying to reshape the metal biter thingy and put it back into the relay QC and snap the top back in.  It's not leaking, but it's definitely weaker than it was before (and hopefully the o-ring isn't damaged from futzing in there.)

I guess now that I know how to work w/ these quick connects I'll try to fix my leaking RO filter.

And then I'll have nothing to do around the house until I break something else!

[Spork]

Just for my curiosity: Was this a Whirlpool?

[dragoncar]

Just for my curiosity: Was this a Whirlpool?

Nah, it's some fancy European company I'd never heard of

[dragoncar]

Ok, I noticed a burning plastic smell tonight and peeked at the new limit switch and it's ALSO glowing red on the (input?) terminal.  Now I'm thinking there's another problem with the oven, but despite my general knowledge of electronics I don't know what would be causing a glowing terminal that isn't related to the terminal itself.  I had assumed the old switch had a loose connection somewhere, increasing resistance, which caused the terminal to glow and further degrade the connection.  But what are the odds the new switch is failing in exactly the same way?  Maybe I need to replace the terminal contact on the oven side? (It's a wire crimped with a push-on terminal like this:



Helps!

Edit:  I sanded down the terminals just in case.  I noticed the push-on connector is now fried (it wasn't, however, when I replaced the switch).  I'll buy a new push-on connector and hopefully connector degradation was the problem.  When I did my initial test after replacing the switch, there was no issue with the terminal glowing.

[Spork]

So... probably totally unrelated, but going back to my "is it whirlpool..."

Whirlpool dishwashers and clothes dryers (not sure about the ovens) have some factory recall with their thermal fuses.  The replacement part comes not just with a new fuse but with new terminals and an additional 6 inches or so of wiring attached to it.  It has a splicing block with little tiny lugs and you cut out the old fuse and splice in an additional 6 inches of wire.  Apparently just pulling the terminals and replacing the fuse is NOT kosher -- the fault lies also in the terminal connections.

Having said that... even replacing it the recommended way, my thermal fuse has gone out multiple times.  I get about a year out of it.

[dragoncar]

So... probably totally unrelated, but going back to my "is it whirlpool..."

Whirlpool dishwashers and clothes dryers (not sure about the ovens) have some factory recall with their thermal fuses.  The replacement part comes not just with a new fuse but with new terminals and an additional 6 inches or so of wiring attached to it.  It has a splicing block with little tiny lugs and you cut out the old fuse and splice in an additional 6 inches of wire.  Apparently just pulling the terminals and replacing the fuse is NOT kosher -- the fault lies also in the terminal connections.

Having said that... even replacing it the recommended way, my thermal fuse has gone out multiple times.  I get about a year out of it.

Thanks, it's not whirlpool but that reminds me I should replace both connectors (I was thinking only to replace the broken one).  I'm not sure what the optimal procedure for that is, hopefully it's ok to just crimp with pliers cause that's all I've got.  I was going to mention before (or maybe I did?) how surprised I am that they run all those amps through these tiny spade connectors.  While we are arguing in another thread about wire gauge for the oven circuit, the problem will almost certainly be the internal wiring if this is how small the wires are.

[zolotiyeruki]

Ok, I noticed a burning plastic smell tonight and peeked at the new limit switch and it's ALSO glowing red on the (input?) terminal.  Now I'm thinking there's another problem with the oven, but despite my general knowledge of electronics I don't know what would be causing a glowing terminal that isn't related to the terminal itself.  I had assumed the old switch had a loose connection somewhere, increasing resistance, which caused the terminal to glow and further degrade the connection.  But what are the odds the new switch is failing in exactly the same way?  Maybe I need to replace the terminal contact on the oven side? (It's a wire crimped with a push-on terminal like this:



Helps!

Edit:  I sanded down the terminals just in case.  I noticed the push-on connector is now fried (it wasn't, however, when I replaced the switch).  I'll buy a new push-on connector and hopefully connector degradation was the problem.  When I did my initial test after replacing the switch, there was no issue with the terminal glowing.

Our oven has a similar situation with some of the terminals--if they're not tight enough, the small contact patch will get very hot, like red hot glowing.

[Greg]

I'm not sure what the optimal procedure for that is, hopefully it's ok to just crimp with pliers cause that's all I've got. 

No, it's not ok.  Crimping this kind of terminal takes a specific tool to do correctly. The standard crimp-on connectors like from an auto parts store are not the correct ones.  You need high-temp ones made for appliances, and you need to use the right crimper for the connection to be tight enough not to cause this problem again.

[dragoncar]

I'm not sure what the optimal procedure for that is, hopefully it's ok to just crimp with pliers cause that's all I've got. 

No, it's not ok.  Crimping this kind of terminal takes a specific tool to do correctly. The standard crimp-on connectors like from an auto parts store are not the correct ones.  You need high-temp ones made for appliances, and you need to use the right crimper for the connection to be tight enough not to cause this problem again.

Well the crimp wasn't the point of failure the first time.  I got appliance connectors but there wasn't a tool so I did a really good job with the pliers.  I might order a tool online if I can find one and snug it up, but it's working fine again.  Honestly I agree you can't just do a quick crimp with pliers, but it's not like it's impossible to do a good job compacting if you are careful. 

Wire length was limited so I didn't cut any off the end-- would people suggest doing this?  If so I'll probably need to pull a whirlpool and create a pigtail type extension and lug connector... Plus high temp shine tubing I suppose.  I'd guess a wire nut won't work but maybe they make special ones for this application.

[Spork]

This is vaguely what the dishwasher fuse replacement looks like:

http://www.amazon.com/Whirlpool-8193762-Fuse-Dish-Washer/dp/B0053F9TLI

Note that it *has* the spade connectors, but they're "pre connected". 

[Greg]

Well the crimp wasn't the point of failure the first time.  I got appliance connectors but there wasn't a tool so I did a really good job with the pliers.  I might order a tool online if I can find one and snug it up, but it's working fine again.  Honestly I agree you can't just do a quick crimp with pliers, but it's not like it's impossible to do a good job compacting if you are careful. 

...I'd guess a wire nut won't work but maybe they make special ones for this application.

A loose crimp can cause resistance and heat at the crimp, but it might not fail there.  Instead the heat can travel to where the tab the connector is molded into the plastic of the thermal fuse thing.  I'm not to criticize your work and accomplishment, but let you know that it does make a difference.

There are ceramic wire nuts for splicing these kinds of wires, often included with generic oven ignitors that require you to splice on the original connector plug.

[dragoncar]

Well the crimp wasn't the point of failure the first time.  I got appliance connectors but there wasn't a tool so I did a really good job with the pliers.  I might order a tool online if I can find one and snug it up, but it's working fine again.  Honestly I agree you can't just do a quick crimp with pliers, but it's not like it's impossible to do a good job compacting if you are careful. 

...I'd guess a wire nut won't work but maybe they make special ones for this application.

A loose crimp can cause resistance and heat at the crimp, but it might not fail there.  Instead the heat can travel to where the tab the connector is molded into the plastic of the thermal fuse thing.  I'm not to criticize your work and accomplishment, but let you know that it does make a difference.

There are ceramic wire nuts for splicing these kinds of wires, often included with generic oven ignitors that require you to splice on the original connector plug.

 Sure, but what makes you say it's loose?