BS: Self cleaning ovens

Subject: BS: Self cleaning ovens
From: number 6
Date: 16 Feb 12 - 11:39 PM

anyone ever use this feature on an electric range .... I've heard it could be a fire hazard, and that it can melt the internal components on the stove panel (especially with the flat top slide in models).

biLL

Subject: RE: BS: Self cleaning ovens
From: olddude
Date: 16 Feb 12 - 11:47 PM

I have and I went back to just hand cleaning. The oven gets so darn hot that I was afraid of fire

Subject: RE: BS: Self cleaning ovens
From: JohnInKansas
Date: 17 Feb 12 - 03:09 AM

We've used the self-cleaning feature fairly regularly on about three different stoves, and never had one in which any exterior surfaces got hot enough to be a concern. The ones with which we used it were self-standing models that sat out in the middle of the room, and weren't tightly encased in cabinetry; but in general if properly installed I wouldn't see a real hazard with them.

There are two kinds, and how you use it might be affected by which kind you have. Unfortunately the User's Manual often doesn't tell you which kind a given stove is.

The "lower temperature" kind uses a catalytic coating on the internal surfaces, so that any crud is oxidized at a somewhat lower temperature. The temperature actually used for a catalytic cleaning usually isn't really significantly lower than for the other kind.

The more common kind is simply called a "pyrolytic" oven, and relies entirely on "burning off" all the grease with high temperature. Most ovens can achieve about 500 F (293 C) for cooking purposes (a good Pizza oven temperature), and the "cleaning cycle" generally doesn't go much beyond that, perhaps 50 F (28 C) higher.

At about 500 F, if you open the door so that you let a little fresh air in, and toss a piece of paper in and shut the door quickly, the paper might "explode in flame," but as long as no fresh air is admitted the cleaning cycle automatically reduces the oxygen inside the oven (by burning off - oxidizing - a little surface grease before the oven gets fully heated) to where there should be almost no visible smoke and no flame.

The oven door must "lock shut" when you start a cleaning, and should remain locked until the oven cools down to near room temperature. You should not be able to open the door until it's cooled, so you should never see a "flame."

With either kind, any grease in the oven should be reduced to a "soft ash" and you still should (the book says) wipe that out when the cleaning is done and things cool down. It depends on how fussy you are.

In the US, it is generally required that a "professional" installer must leave a copy of the installation instructions with the new owner, so it should be fairly easy to check whether it looks like the instructions were followed. (State and local rules may vary on this.) Properly installed, as specified by the manufacturer, and operated according to instructions, there should be no particular hazard associated with the automatic cleaning cycle.

A DIY installation by an amateur, or installation of a "used" stove where the paperwork is missing, might merit a little extra caution, but the requirements to do it right really aren't all that complex.

John

Subject: RE: BS: Self cleaning ovens
From: banjoman
Date: 17 Feb 12 - 06:52 AM

From my experience Self Cleaning Ovens don't. We have found an excellent guy locally who cleaned our"Self Cleaning Oven" till it looked like new and all for a very reasonable charge. He used just washing up liquid, very hot water and lots of elbow grease.

Subject: RE: BS: Self cleaning ovens
From: Greg B
Date: 17 Feb 12 - 09:34 AM

If you have a laminate counter-top, you may find that the exterior gets hot enough to release the glue on the edges that are nearest the range. Two houses, two self-cleaners, two loose pieces of laminate...

Subject: RE: BS: Self cleaning ovens
From: Jim Dixon
Date: 17 Feb 12 - 11:04 AM

If you don't have an owner's manual for any appliance, you can usually go to the manufacturer's website and download a copy.

Subject: RE: BS: Self cleaning ovens
From: pdq
Date: 17 Feb 12 - 11:14 AM

I tried it one time with my electric stove.

I put four unusable black grungy old cast iron skillets in and shut the door.

It took a couple of hours but the ironware was perfect, just a little gray powder that I blew-off with compressed air. Greese thoroughly with Crisco and don't let them touch water when freshly cleaned.

Subject: RE: BS: Self cleaning ovens
From: gnu
Date: 17 Feb 12 - 01:13 PM

Great tip pdq.

Subject: RE: BS: Self cleaning ovens
From: JohnInKansas
Date: 17 Feb 12 - 03:06 PM

The oven method for cleaning cast iron skillets can be used in any oven that will get to about 425 F or above. A similar effect can be achieved by putting an empty cast iron skillet (or stew pot, etc) directly in the coals of a campfire overnight. You should wipe out any loose excess before "cleaning" this way, since "clumps may leave bumps" when everything else is mostly done.

The only difference I'd suggest is that "raw" animal fat works better than Crisco or other "processed greases" in our opinion. Frying some bacon the morning after you've done the cleaning works fairly well, but one of the best methods for re-coating the working surfaces is to make toast by "frying" a couple of slices of buttered (not margarine) bread for breakfast. After the first cooking, use a paper towel after the skillet cools to wipe the excess grease around to coat all the sufaces, inside and out.

If you wipe down the cleaned skillet with your grease of choice and set it back in an oven that's about 200 - 250 F and leave it there (with the oven door shut) until it all cools, you can also get a decently "cured" finish thats good enough to start using the skillet normally.

What you use for the reseasoning is largely a matter of preference (and what you have most conveniently), of course. The nice thing about cast iron is "it ain't fussy."

John

Subject: RE: BS: Self cleaning ovens
From: Joe Offer
Date: 17 Feb 12 - 07:31 PM

I've found that the self-cleaning feature on our GE oven works pretty well. I have to do it when my wife's on vacation, because she can't stand the smell.....

Subject: RE: BS: Self cleaning ovens
From: number 6
Date: 17 Feb 12 - 07:45 PM

We just replaced our 26 year old range with a new flat top slider that has the self cleaning feature. The auto clean pumps up the oven to around the 900c point (that is hot) and burns away for about 4 hours. The stove must be glowing red. Sounds dangerous to me. The stove is also digital, if the house doesn't catch fire it must surely burn out the mother board.

Anyway, Ann my wife is pro auto clean, while I'm certainly not. We've been arguing about it for the last day or so. She says she's going to push me in the oven and crank it it up full tilt.

Oh well, thanks for the input everyone.

biLL

Subject: RE: BS: Self cleaning ovens
From: Janie
Date: 17 Feb 12 - 09:10 PM

My sister just installed a 1 year old drop in electric range for me with a self-cleaning oven. I do have the owner's and installation manual and know she did it "according to Hoyle" but the drop-in range I replaced was installed when the house was built, in 1968. I don't even know if they had self-cleaning ranges then.

Until I read this thread it did not occur to me to be concerned. Still not sure I need to be, but just in case....any concerns about installation into a spot designed for a drop-in 44 years ago?

Subject: RE: BS: Self cleaning ovens
From: JohnInKansas
Date: 18 Feb 12 - 05:30 PM

Janie -

The installation instructions should tell you what's required for a safe installation. The things you need to look for in the instructions are any needed clearances around specific parts of the stove, and special materials recommended to provide heat barriers, if there are any. There may sometimes be an instruction about "venting" the surrounding spaces. (A few stoves, self-cleaning or otherwise, may recommend a hole in the counter top or other means of allowing hot air to circulate out of an enclosed space if the space is small.)

biLL -

The heating elements commonly used in stoves have a Nichrome or similar wire that gets hot. The maximum temperature at which the wire can be operated without melting or rapid burnout is generally given as 1700 F, or ~925 C.

The top cooking surface "burners" are generally controlled in an "open loop" fashion in which a small heater in the control knob is heated by the current delivered to the cooking area, and when the knob gets hot the current is cut off. In most stoves, nobody knows "how hot" a given "burner" is, as there's no sensor to tell you and the temperature depends on what you're cooking on it, so they warn that the "cooking surface may reach 1700 F (~900 C). This only happens if there's no pot on the burner, and in actual practice even then the exposed surfaces are unlikely to get to that temperature.

Most ovens have a temperature sensor in the oven that controls when the power turns on or off, so that you can actually set a temperature and that's what you'll get. (Althought few ovens actually settle within about 15C of what the knob says.) I haven't heard of a self-cleaning oven that uses an actual oven temperature higher than about 650 F (about 350 C). The heaters in the oven may cycle fairly rapidly at that tempeature, and in each cycle the elements may get close to your 900 C, but I doubt if the actual oven temperature gets anywhere close to that. The "cleaning temperature" generally is close to the hottest baking temperature you can set, but isn't likely to be all that much higher.

Putting an oven thermometer in the oven during a cleaning cycle isn't recommended, since the radiant heat would likely bring the thermometer to quite a bit higher temperature than the actual oven air temp. Destruction of the thermometer is likely, and a reading wouldn't be accurate anyway. 600 F (315 C) is red hot, but only if you turn the room lights down so you can see it. (It's a very dim red.)

John

Subject: RE: BS: Self cleaning ovens
From: Q (Frank Staplin)
Date: 18 Feb 12 - 05:42 PM

I wonder if a self-clean oven would reduce Santorum to powder?

Subject: RE: BS: Self cleaning ovens
From: Janie
Date: 19 Feb 12 - 09:21 AM

Thanks John. I guess I need to look at the manual then check with Annie to make sure she followed any instructions regarding that.

Subject: RE: BS: Self cleaning ovens
From: JohnInKansas
Date: 19 Feb 12 - 04:59 PM

I have found a few web sites that parrot the 900 C cleaning cycle thing, but that temperature is very near the maximum for the heating elements and I'd need to see some better documentation before I'd believe it. (None of the sites gave any source citations to credible authorities.)

Our somewhat dated oven takes about 20 to 30 minutes to preheat to a typical 375 F so a rough extrapolation estimates about an hour (at full power) to come to the 600 F. A cleaning cycle for that stove heats for about an hour, and "sustains" for roughly another hour with the heater cycling on/off, but the oven stays locked for a little more than another two hours while the oven cools down to where the door can be opened. Total cycle a little over 4 yours, more than half of which is spent cooling down.

Outside surfaces don't seem to get above about 150 F for any of ours, but they might go a little higher on one enclosed in cabinetry.

Even if you don't use the self-cleaning feature, an oven with that capability will have more insulation, and claims that normal cooking will be slightly more economical probably have some basis, although it's hard to generalize. In the US, new appliances have an "energy rating" that's probably a better guide. Sources that claim the better efficiency also suggest that using the cleaning cycle more than about monthly will probably obliterate any savings, since the cleaning eats lots of watt-hours, but they don't give any basis (how frequently do you bake?) for that recommendation.

Some sources do warn that you should move your small birds out of range while doing a cleaning, and the truly paranoid recommend covering acquariums and turning off the air pumps due to the "noxious gases" produced by cleaning. Some exotic birds are sensitive, and might be affected by the small amounts of gases produced -- perhaps(?). There is sometimes a slight "odor" from running the cycle with ones I've used, but that does also depend on how dirty it was (and what the spills were). I never noticed any adverse effect on acquariums that I used to have (they were so overpopulated that turning off the air even for a little while would have killed everything; and we've never (intentionally) had birds in the house to observe. (When the cats occasionally brought one in and turned it loose we weren't cleaning the oven.) Turning on the kitchen exhaust fan for a while, if you have one that exhausts outside and if you have any reason to worry, or if the slight odor bothers you, would seem sufficient from what I've observed.

John

Subject: RE: BS: Self cleaning ovens
From: Janie
Date: 19 Feb 12 - 05:54 PM

Took a look at the installation instructions, measured, then called amazing sister Annie to confirm she was mindful of all the clearances during installation. Have absolute confidence I can use the self-cleaning cycle without fear of roasting the house.

Although my life-long motto has been "nobody ever died from oven-crud" I did once have the crud ignite, and so have been somewhat conscientous since about making with the Easy-Off periodically. Hateful chore. I'm gonna relation the self-cleaning feature.

Subject: RE: BS: Self cleaning ovens
From: number 6
Date: 19 Feb 12 - 06:55 PM

Thanks John .... your technical expertise is very much appreciated as always.

Our new stove is a Maytag slide-in. The standard for all cabinet slide-in models is a 30 inch box. There should be at least 4 inches between the stove and the wall at the back with 1/4 inches at the sides of the cabinets. The safety of the stove depends on how well it is insulated. How do we determine how well the stove is insulated, that is the question as there is no regulation measuremenst in print.

BTW .... our stove has 3 modes of auto clean

1. very hot .... auto clean time 2 hours
2. very, very hot .... auto clean time 3 hours
3. f&@king hot ... auto clean time 4 hours

I'd think I would not take options 2 and 3

With newer digital models of stoves which run off of 'mother boards' much like computers, surely the auto clean function must affect the longevity of this computer.

biLL

Subject: RE: BS: Self cleaning ovens
From: JohnInKansas
Date: 19 Feb 12 - 07:28 PM

Janie -

I would expect that any extra insulation would all be enclosed inside a housing so that you couldn't remove it during installation. You have to trust the manufacturer that the "innards" that do what they promise will be securely attached, if they don't include specific instructions for what "loose stuff" is essential for proper installation.

While the longer cleaning cycles give more time to make sure everything inside gets up to temperature, and stays hot enough for the reactions that get the crud broken down, they don't necessarily mean that the outside (or even the inside) surfaces get to a higher temperature. The longest time may, in fact, run a little cooler since the cleaning action doesn't have to be "hurried."

The longer cycle may also get things sufficiently "cleaner" that you don't have to run another cycle as frequently.

In stoves in general, all the "sensitive" controls generally are in the "console" where they're about as far from anything hot as possible. About the only thing actually exposed to "cooking temperatures" would be the temperature sensor in the oven. The "electronics" that read even that temperature usually are up in the console/control-panel where the knobs are.

If the knobs don't sizzle when you spit on them, it's unlikely that any excessiveley rapid destruction of the electronics is going to be a problem. Given that stoves are "utilitarian commondities," they generally don't install aerospace/rocket-ship quality components, so maintenance and repair rates aren't spectacular; but the kind of stove doesn't seem to have much to do with it, other to make the replacement parts a little more expensive if you get something really fancy.

John

Subject: RE: BS: Self cleaning ovens
From: Janie
Date: 19 Feb 12 - 07:56 PM

Thanks John. I think you meant to direct your response to biLL.

Subject: RE: BS: Self cleaning ovens
From: JohnInKansas
Date: 19 Feb 12 - 10:26 PM

Janie -

I thing you're right.

That's what I get for breaking mudcat tradition and reading two prior posts before responding.

Confused ....

John

Subject: RE: BS: Self cleaning ovens
From: Janie
Date: 20 Feb 12 - 05:11 AM

lol!

Subject: RE: BS: Self cleaning ovens
From: gnu
Date: 20 Feb 12 - 04:48 PM

sIx... "1. very hot .... auto clean time 2 hours
2. very, very hot .... auto clean time 3 hours
3. f&@king hot ... auto clean time 4 hours"

Seems bassackwards to me. The hotter - the MORE time?