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"Hacking" Pyrolytic ovens to utilise high heat


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#1 infernooo

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Posted 26 May 2007 - 11:34 PM

Hi folks!

Now just a quick disclaimer before I start. I know some of you will have reservations/problems with what I am asking, but hey, I'm the only one who will end up burned/injured.

OK, it has to do with my obsession to find the hottest equipment around for re-creating restaurant food at home. It first started with Chinese wok burners (I am satisfied now that I have a burner comparable, if not hotter than 90% of Chinese restaurants), then moved onto tandoor ovens (I actually purchased one, but had to sell it due to relocation).

Now I want an oven that gets as hot as a wood fired oven. Yes I know I _COULD_ build one or have one custom built for me, or even buy one, but I don't want a wood-fired oven - I have no room for it, so I would rather use my oven space.

I have noticed that a lot of the higher end ovens nowadays come with Pyrolytic cleaning - they have a cleaning option that sends the temperature of the oven above 500 degrees C (930 F) - the realm of wood fired and tandoor ovens, allowing food to be cooked in single digit times with crisp outsides, moist insides etc.

The problem is that for "safety" (yes I can see that it is a sensible feature, but hey, I'm a food nerd, I would rather take a risk and be able to churn out a damn good pizza - and yes I do have a stone and yes I have tried preheating at maximum temperature etc, don't start :-)) reasons, the oven door locks when the cycle is turned on (and usually lasts anywhere from 30-90 minutes).

My question is this - would "hacking"/modifying one to bypass the door-locking mechanism be hard? Without actually owned one (yet), I can't investigate for myself... can those of you who own Pyrolytic ovens perhaps chime in please?

Thanks everyone!

#2 joesan

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Posted 27 May 2007 - 04:54 AM

Infernoo - So your nickname is very apt!

I don't think that it would be hard to hack these ovens. Most probably the door is kept closed by a door interlock mechanism such as a little solenoid that pushes a little bar and locks the door. Disable the solenoid, most probably by simply removing a wire from the solenoids power supply, and you have the ability to open the oven door whenever you need it.

I'd like to do this to my oven also and for the same reason as you (pizza). My oven doesn't have pyrolytic functions as only the top of the range oven had that. However I am quite sure that all these oven have the same functionality as each other and that the capability to switch on the extra features is there on most models. You just have to find out how to do it. I am researching how to do it on the Gaggenau ovens but there is not a lot of information out there. One idea I have was to disable the temperature regulator and then control the oven using a PID. Basically then the elements run at full whack until you throttle them back to whatever you require. I feel quite sure that the Pyrolytic ovens don't have any special elements to make them go hotter but they may have better insulation to protect the surroundings. If you use a PID you have the advantage of super precise temperature control at any level.

PS Can you tell us how you got high powered wok burner? I'd like to try that myself.

Edited by joesan, 27 May 2007 - 04:56 AM.


#3 cdh

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Posted 27 May 2007 - 06:03 AM

Talk about timing- Look what appeared on Slashdot yesterday.

Looks like a patent for another method of throwing massive heat by infrared radiation expired recently and is getting incorporated into grills right now. 900F is attainable in a different way now... and pizza cooks very well on a grill.
Christopher D. Holst aka "cdh"

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#4 brucedelta

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Posted 27 May 2007 - 10:28 AM

Disclaimer: Mty expirimantation so far has been with a oven that I already wish to replace, so I am not taking a big risk.

Jeff slice NY page is the site that got me interested in this expirimantation.

I had a semifunctional lock already and was able to disable it. UIsing a stone and the cleaning cycle of the oven I was able to get the stone to almost 800 deg (I have a infared thermometer so I believe my measurment accurate).

Bottom line is that one can make great home pizza in a very hot oven, but much experimenting and work is required, it is continuing for me. Keep in mind the behavior of the oven changes in this mode. The oven light does not work. You can not just turn it off and back to normal it needs to cool down. The broiler is hotter than you ever imagined.

At your local pizzaria it is common to see the guy reaching in the oven to check things out, a home oven is very different. The cavity ir small relative to commercial unit and you can not get anything very far away from that broil element. I reached in to try to adjust toppings after putting a pie in and had to pull my hand out immediatly, but the hairs on top of my arm were all burned off, so be carefull.

I follow the common practice of using towels instaed of potholders as discussed on another thread. Well towels singe at this heat and are not thick enough. I thought the only thing to watch out for would be letting a loose end hit the lower element. My pizza peel now has professional looking char marks on it.

The upside is fast and crispy thin crust pizza. Jeff on his page talks about using a tin foil tent to shield the burner and I think that is my next expiriment. I tried to make a white pizza with garlic, olive oil, and riccota cheese. The burner is to close for the olve oil and smokes it.
My experience is that the less is best topping philiosiphy applies, otherwise the crust buurns before the toppings are done. Jeff suggests dealing with this by using a cold sheet pan to cool the stone, but I have not tried that yet.

So you probably want to know how to modify the over, but I can offer very little help there. My oven already had a buggered up lock and I just removed a screw and the latch stays out of the way. I really am wanting to replace this oven and have been enquiring about modifying a new unit and all dealers say it voids the warrentee and is against the rules. They also privatly concede that it sounds cool to have high temp pizza. I recently attended a demo dinner at the local wolf distributor and discussed the idea. While it was agreeded that the high temp pizza was a good idea, they said they saw no easy way of doing it and the factory would not look favorably upon such a modification.

So maybe I keep my old oven for this reason. I have two ovens and fear replacing only one will be a poor cosmetic choice. But I will probably be next trying high temp pizza again this week. Also keep in mind you heed about 1 hr for the oven to heat up.

#5 ray goud

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Posted 29 May 2007 - 07:14 PM

Infernoo - So your nickname is very apt!

I don't think that it would be hard to hack these ovens. Most probably the door is kept closed by a door interlock mechanism such as a little solenoid that pushes a little bar and locks the door. Disable the solenoid, most probably by simply removing a wire from the solenoids power supply, and you have the ability to open the oven door  whenever you need it.

I'd like to do this to my oven also and for the same reason as you (pizza). My oven doesn't have pyrolytic functions as only the top of the range oven had that. However I am quite sure that all these oven have the same functionality as each other and that the capability to switch on the extra features is there on most models. You just have to find out how to do it. I am researching how to do it on the Gaggenau ovens but there is not a lot of information out there. One idea I have was to disable the temperature regulator and then control the oven using a PID. Basically then the elements run at full whack until you throttle them back to whatever you require. I feel quite sure that the Pyrolytic ovens don't have any special elements to make them go hotter but they may have better insulation to protect the surroundings. If you use a PID you have the advantage of super precise temperature control at any level.

PS Can you tell us how you got high powered wok burner? I'd like to try that myself.

View Post

I have seen the insides of a couple of older self-cleaning ovens, and they didn't use the easily-defeated solenoid method; they used a bi-metallic strip which bent under the influence of heat and mechanically locked the door closed - thus the reason for the time delay (cool-down time). Perhaps a VERY handy person could defeat this lock. But only if it also did not close another switch in the oven electricals. We need some "major appliance" repair people to chime in.
Ray

#6 infernooo

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Posted 30 May 2007 - 07:00 PM

Thanks for the replies folks!

I think I need to make a visit to my local kitchenware shop and do some "browsing"... I will report back this weekend after I have had a chance to do some snooping!

Cheers

#7 infernooo

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Posted 30 May 2007 - 07:10 PM

Joesan: I'm sorry, I totally overlooked your question.

Basically I got a few types of burner, varying from unbelievably powerful, to ridiculously powerful. You really need a heavy wok to distribute the heat properly (either a thick traditional carbon steel or something similarly hefty) otherwise you will burn anything you cook if you look away for more than about 5 seconds.

There are 2 types of burners to look at if you want serious heat (and don't forget you need the supporting parts too):

Mongolian 32 jet burner: Posted Image

Duckbill burner: Posted Image

You will also need something to sit these on (e.g. don't put them directly on wood), an appropriate pressure regulated hose and an LPG tank (or you can use NG, just buy the NG version).


Some of these babies will give you about ~180,000 BTU

Edited by infernooo, 30 May 2007 - 07:13 PM.


#8 ray goud

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Posted 31 May 2007 - 02:51 PM

Infernoo - So your nickname is very apt!

I don't think that it would be hard to hack these ovens. Most probably the door is kept closed by a door interlock mechanism such as a little solenoid that pushes a little bar and locks the door. Disable the solenoid, most probably by simply removing a wire from the solenoids power supply, and you have the ability to open the oven door  whenever you need it.

I'd like to do this to my oven also and for the same reason as you (pizza). My oven doesn't have pyrolytic functions as only the top of the range oven had that. However I am quite sure that all these oven have the same functionality as each other and that the capability to switch on the extra features is there on most models. You just have to find out how to do it. I am researching how to do it on the Gaggenau ovens but there is not a lot of information out there. One idea I have was to disable the temperature regulator and then control the oven using a PID. Basically then the elements run at full whack until you throttle them back to whatever you require. I feel quite sure that the Pyrolytic ovens don't have any special elements to make them go hotter but they may have better insulation to protect the surroundings. If you use a PID you have the advantage of super precise temperature control at any level.

PS Can you tell us how you got high powered wok burner? I'd like to try that myself.

View Post

I have seen the insides of a couple of self-cleaning ovens, and they had a bi-metallic strip acting as the interlock device: completely mechanical and not easy to defeat unless one is VERY handy with tools and mechanical devices. And that does not consider whether the particular oven also has an electrical interlock to prevent high heat if the bimetal fails.
Ray

#9 budrichard

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Posted 01 June 2007 - 12:51 PM

There needs to be a bit of sanity injected into this Thread.
I can think of a number of reasons why one would not defeat an interlock without obtaining the express consent of the OEM (Original Equipment Manufacturer).
One doesn't know ALL the reasons for the interlock and the DANGERS associated with removal. I suspect these devices have a timer to limit the amount of heat produced, if the cleaning feature was left on long enough, the insulation might start to break down. As correctly pointed out, the insides will be extremely hot if you defeat the time delay.
Anytime one defeats a protective device or interlock, one is aksing for an accident. Anytime one defeats a protective device or interlock without contacting the OEM, one is not being smart.
BTW, abrief Internet search found the following:
"In a known manner, the oven cavity 18 can be highly heated to a temperature in excess of 750° F., wherein the walls of the oven chamber or cavity 18 are self-cleaned by pyrolytic action. Such a phenomenon is more fully detailed in U.S. Pat. No. 3,121,158 to Hurko, the entirety of which is herein incorporated by reference. During a pyrolytic cleaning cycle, it is imperative that the oven user not be able to open the oven door 20, since the rapid influx of oxygen-rich air into the cavity 18 could result in an explosion of combustible gases generated therein, or hot, noncombustible gases escaping from the oven could injure the user. "
http://www.patentsto...escription.html
-Dick

Edited by budrichard, 01 June 2007 - 01:00 PM.


#10 andiesenji

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Posted 01 June 2007 - 03:00 PM

Now, if you want really high heat - - - -
Consider an electric glass furnace or a glass kiln - kiln is more compact.
Paragon glass equip.

There is a tradition in certain glass-blowing studios to cook a special occasion dinner in the glass furnaces.

Kingdom of Crystal, Sweden
Kosta Boda, etc. Scroll down a bit more than half way to see the reference.

You don't want a gas furnace because the only way to crank up the temp to where it will melt glass is to force oxygen into the mix. This is not for amateurs.
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#11 infernooo

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Posted 15 August 2008 - 12:55 AM

So I now can check off another item from my most wanted list of gadgets...

I purchased a brand spanking new pyrolytic oven (an absolutely stunning oven made in Italy) for a killer price through an excess stock auction online. Once it arrived and I had an authorised electrician install it (I asked him to put in a switch on the near by power point so I could easily cut power to it if I wanted too), I got to work on figuring out how the pyrolytic function worked and the safety features I would have to circumvent.

It was a helluva lot easier than I had planned - the safety locking mechanism was an electronically actuated steel arm which swings out and locks the door closed once the temperature goes past a certain point. At first I put a piece of aluminium foil to block it from latching on, but that resulted in an error code being displayed and refusal to start the pyrolytic cycle. So, I figured that the oven just actuates this arm, and when the arm reaches a certain angle (there were no contact electronics), it sends a signal indicating it has locked on.

So I simply cut off its arm. Now it swings its little arm and thinks it has locked the door, but I can freely open it!

I now have a domestic home oven that does everything I could possibly want (it even has a proving function and steam injection for baking) that can reach and maintain temperatures of 1000f (560c) - PERFECT for replicating a tandoor oven or woodfired oven.

Here are pictures, including one of the oven from the outside, one of the locking mechanism (hard to see), one of the cut locking mechanism, one of me using my laser gun during the pyrolytic cycle, and one screenshot showing the temperature of the oven during the 3 hour pyrolytic cycle (you can set it to however long you want).

Posted Image

Posted Image

Posted Image

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#12 dougal

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Posted 15 August 2008 - 04:04 AM

Nice hack(saw) job!

Care to share the make and model, in case they are being sold off elsewhere? :cool:
"If you wish to make an apple pie from scratch ... you must first invent the universe." - Carl Sagan

#13 KennethT

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Posted 28 August 2008 - 06:32 AM

Infernoo - that is awesome!!! Plus, I'd imagine that any cooking you do at that temperature will have the added benefit of cleaning the oven at the same time :) haha..

I've been thinking about making a "benchtop tandoor" recently... I was thinking I could make a 5 walled cube out of 2" thick poured concrete, then stick some red hot coals in the bottom - that way you get the charcoal smoke and the heat... any ideas about how to go about this???

I'm a little worried that normal concrete (not the quick drying vinyl stuff) may give off some funky tasting/smelling/potentially hazardous fumes when it gets really hot though...

Any ideas from all the pyros out there???

#14 Joe Blowe

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Posted 28 August 2008 - 09:02 AM

I've been thinking about making a "benchtop tandoor" recently...  [...] Any ideas from all the pyros out there???

View Post

It's off-topic for this thread, but I'll indulge you :biggrin:

http://www.google.co...l drum tandoori
So we finish the eighteenth and he's gonna stiff me. And I say, "Hey, Lama, hey, how about a little something, you know, for the effort, you know." And he says, "Oh, uh, there won't be any money. But when you die, on your deathbed, you will receive total consciousness."

So I got that goin' for me, which is nice.

#15 infernooo

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Posted 01 September 2008 - 03:55 PM

Infernoo - that is awesome!!!  Plus, I'd imagine that any cooking you do at that temperature will have the added benefit of cleaning the oven at the same time :) haha..

I've been thinking about making a "benchtop tandoor" recently...  I was thinking I could make a 5 walled cube out of 2" thick poured concrete, then stick some red hot coals in the bottom - that way you get the charcoal smoke and the heat...  any ideas about how to go about this???

I'm a little worried that normal concrete (not the quick drying vinyl stuff) may give off some funky tasting/smelling/potentially hazardous fumes when it gets really hot though...

Any ideas from all the pyros out there???

View Post


Hi Kenneth!

Here are some bookmarks I had before I decided to by a tandoor oven (which I sold shortly afterwards due to having to relocate :-():

http://piers.thompso....com/index.html
http://www.cpsusa.co...tandoorOven.htm
http://www.geocities.../3012/page2.htm
http://www.villagok....door/index.html
http://oildrumtandoor.blogspot.com/

#16 adey73

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Posted 02 September 2008 - 04:26 AM

I've got a tandoor and although it gets super hot, when the chicken goes in the heat drops as the juice drip on the coals. Anyone got any ideas?
Posted ImagePosted Image
Posted ImagePosted Image
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#17 infernooo

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Posted 02 September 2008 - 07:51 PM

I only have a few thoughts...

1.) Traditional restaurant tandoors have VERY thick walls and are often surrounded by stainless steel to further retain heat. The one I purchased weighed an absolute ton! (I just checked the specifications from when I bought it, and for a "small" sized one, it weighed 300kg = 660lb !) This would make a HUGE difference in being able to retain heat once food is added. They also use a LOT of charcoal to keep the overall thermal mass high.

2.) The lid should be fairly tight fitting even with the skewers protruding from the top.

3.) The restaurant tandoors also have air vents in the bottom like charcoal grills which allow you to increase or decrease the airflow underneath the coals to get things even hotter.

#18 joesan

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Posted 09 September 2008 - 06:52 AM

Infernooo - you are the man! I just chanced upon this thread again and I see that you've got the pyrolitic oven of your dreams. What make did you go for?

I haven't been able to find any information on overriding my Gaggenau oven (I also want to be able to replicate woodburning temperatures for pizzamaking). I may have to look at alternative ovens.

I see that you are using a DAQ - any plans to computer control your oven? :biggrin:

Cheers

#19 infernooo

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Posted 09 September 2008 - 07:36 PM

Hiya Joesan :-)

I ended up getting the Smeg SCP112X (Pyrolytic Function, Pizza Function, Bakers Steam function, Bakers Proving function, Defrost Function). It absolutely rocks...

It holds the temperature quite steady too: I set it to 80c to make some homemade cheese (more like cream cheese) and monitored it for 8 hours with the USB temp datalogger, and it fluctuated between 78 and 83 the entire time.

I would computer control it, but it already does everything I need ! :-)

The only down side is you have to be VEEEEERY careful when cooking using the pyrolytic cycle. Oven mitts melt if they touch the inside of the glass door (yes that is from experience) and just like a tandoor oven, you could very easily burn yourself putting in or removing naan breads (or any other food being cooked for that matter - luckily this piece of advice is NOT from experience).

Edited by infernooo, 09 September 2008 - 07:37 PM.


#20 joesan

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Posted 10 September 2008 - 05:09 AM

Hee hee - cool... looking forward to seeing the pictures of the food results!

#21 adey73

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Posted 10 November 2008 - 03:37 AM

Infernooo you're house still standing? :biggrin:

Have you got any more results from your oven to share?
“Do you not find that bacon, sausage, egg, chips, black pudding, beans, mushrooms, tomatoes, fried bread and a cup of tea; is a meal in itself really?” Hovis Presley.