Yet another home oven modification

dimarem · June 14, 2009, 09:23:15 AM

Hello everyone - new member, first post.

This oven mod won't be for everyone but if you have a modest electronics / technical background you can do this. My electric oven has electronic controls so it isn't as straightforward as my old one with the knob. The temperature sensor in the oven is basically a device whos resistance increases with an increase in temperature. For example,

Degrees F Resistance
200 1350 ohms
400 1753 ohms
600 2142 ohms
800 2516 ohms

The control circuitry monitors this resistance to determine when to switch the heating elements on or off to maintain the desired temperature. By putting a 10,000 ohm resistor in parallel with the sensor I effectively lowered its output resistance. This fools the control circuitry into thinking that the oven is cooler than it really is, thus the control circuit keeps the elements on longer. I have my oven at around 700 degrees now - a lot better than the 525 I could get before. As I said it is not for everyone and you'd have to be a bit crazy and do it for the love of the pie - but then aren't we all like that ?

scott r · June 14, 2009, 10:19:44 AM

brilliant! now, the question is...is there room to run the wiring so that you can put a switch somewhere to remove the resistor from the circuit? If I couldn't switch back and forth with my oven it would render my oven unusable for a number of dishes I like to prepare.

dimarem · June 14, 2009, 10:36:20 AM

Yes - there is plenty of room in the part of the oven that contains the control circuitry. What I did was mount a small toggle switch at the front of the oven and mounted it such that the handle sticks out of one of the vent holes in the front. The switch basically does this:

<------->--------------------------|
< 10 K ohm >
to control > < Resistive Temperature Sensor
circuit switch |__> normal mode >
<
pizza mode >
<--------|-------------------------|

scott r · June 15, 2009, 12:22:31 AM

this is awesome. moving into my new place with a new oven this week. can't wait to wire it up.

pizzacommander · May 19, 2010, 10:25:18 AM

Not sure I'll get a reply, but this is strictly for electric ovens, correct?

Jackie Tran · May 19, 2010, 10:37:22 AM

Yes i would think so. I'm quite dumb when it comes to this stuff and would likely screw something up. Wood and fire I can work with.

I'm amazed though that you guys can figure this stuff out.

dimarem · May 19, 2010, 12:38:19 PM

Yes, this would be for electric ovens. if you need more info you can email me if you like.

SELES · September 05, 2011, 06:56:42 PM

If a Gas oven is electronically controlled this should work, right?

dimarem · September 07, 2011, 10:09:08 AM

I'm not that familiar with how gas ovens maintain temperature so I would not want to hazard a guess. The concept put forward in this thread assumes that a resistive temperature sensor inside the oven cavity is monitored by the electronic control circuitry which then cycles power on and off to the heating element. I would be extremely careful when working in the gas world!

denrayr · September 08, 2011, 05:15:25 PM

Yes, as long as the gas oven uses an electronic control, it will be the same method.

I've done a little math and determined that with a 10k ohm resister the oven set at:

525 will really be 800 degrees
475 will really be 700 degrees
406 will really be 600 degrees

A few words of caution. Door glass is very sensitive at higher temperatures so be careful not to bump or spill anything on it. The extra heat is a huge safety issue with children or pets around so be careful.

I wouldn't attempt this if your oven isn't a self clean model. Self cleaning ovens are made quite a bit differently in order to handle the extra heat. If you attempt this with a standard cleaning oven you risk melting wires and causing a short circuit. You also risk causing damage to near by fixtures such as cabinets, flooring, and countertops.

denrayr · September 21, 2011, 08:19:13 PM

Well I finally pulled the trigger on installing my turbo switch. Here is a guide on how I did it.

First I removed the control console access panel.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0343.jpg

Next I located the temp sensor wires. Usually the wires are the same color and placed next to each other on a molex plug.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0344.jpg

Most ovens use a standard RTD1000 sensor. Some older ovens used a different style sensor. Before going to the trouble to install your switch, you might want to verify your oven has the correct style sensor. An RTD1000 will read between 1080 and 1100 ohms at room temperature.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0346.jpg

I wanted the cleanest install possible. I decided to pull the wires out of the connector and make my connections there. I carefully pried the release tabs inside the connector and pulled the wires out.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0347.jpg

The switch is just a basic single pole switch. I soldered a length of high temp rated wire to each side.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0349.jpg

I soldered one of the high temp wires directly to one of the sensor wires. Next I soldered the other high temp wire to the 10k ohm resister and the resister to the other sensor wire.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0350.jpg

I reinstalled the wires back into the molex plug and plugged it back into the control board.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0351.jpg

Last, I mounted the switch and reinstalled the access panel.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0352.jpg

After an hour preheat with the oven set to 405, my probe in the oven is reading 603

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0353.jpg

And the stone is reading 675

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0354.jpg

I haven't actually made a pizza yet, but I will post back with the results as soon as I do.

EDIT: I guess the forum doesn't allow embedding images so i changed them to direct links.

EDIT #2: As I stated in a previous post, it doesn't matter whether your oven is gas or electric. They use the same temp sensors. My oven happens to be gas.

scott123 · October 03, 2011, 09:54:53 AM

This is a little late, but, really nice job, Denrayr.

Hdale85 · October 17, 2011, 12:45:17 PM

If your oven is a self cleaning model then there shouldn't be much risk of running it at 700-800 degree's right? How do you guys keep track of oven temps? Just by measuring the stone or do you use a thermometer with a remote probe as well?

scott123 · October 17, 2011, 01:26:24 PM

Harold, if I keep my oven at 600 for longer than about an hour, my self cleaning light comes on, so I'm thinking self cleaning peak temps will range from 600 to 800. I don't think I'd feel comfortable about pushing my oven to 800, though. Basically, ovens are wired with heat resistant wire. If the wire hits a particular temp, the coating will burn. They're insulated to protect the wire, but this insulation doesn't guarantee you extremely high temps.

You read a lot of stories about people running the self cleaning cycle during the holidays, only for the oven to die, leaving them with a turkey crisis. Self cleaning temps are hard on ovens. I think once or twice a year is not that bad, but hitting self cleaning temps once a week for pizza is most likely going to shorten it's lifespan. This is why I'm a huge advocate of shortening baking times with thicker, more conductive stones, rather than extreme temps. With some especially weak ovens, you have no choice but to use a thick, conductive stone AND an oven mod, but the oven mod is never that drastic- 100 degrees at the most. With the right stone, there's zero risk to the oven.

I see from your earlier posts that you were originally from Pittsburgh. What were your favorite pizzerias there? What style are you striving for? The style dictates the bake time, which, in turn, dictates the oven setup.

The most popular method of measuring oven/stone temps is an infrared thermometer.

Hdale85 · October 17, 2011, 02:33:42 PM

We like lots of styles honestly, There is this place called Cafe Milano (they have 3 locations 2 of which are called Pizza Milano) and another place is Little Chicago's Pizzeria (closed now). Those were our 2 favorite places. Sometimes I'm in the mood for a thinner crispier crust and other times I want that nice thicker crust with the crispy outer exterior. What interests me most is of course flavor. Around here we just don't have a lot of offerings past Domino's and Little Caeser's which are not my idea of good pizza? Passible and edible yes, but I think I can do a lot better.

scott123 · October 17, 2011, 04:18:08 PM

Harold, I was just making sure that you're not a huge Neapolitan pizza fan. As long as you're willing to wait until you've got a wood fired oven to make Neapolitan pizza, you can make any other style with 1/2" steel plate and an electric oven that will hit 550- no cleaning cycle, mods or tricks.

Hdale85 · October 17, 2011, 04:25:14 PM

Well I do like Neapolitan pizza as well

I think I'm going to make an LBE though, I found a brand new Weber One Touch Silver 18.5" grill on CL for 30 bucks so that should be a pretty good basis, and a lot of people seem to make Neapolitan and all other types with good results on these.

Either that or I thought about making a wood burning fire clay type oven on a movable cart (since I rent) but I'm not sure how much cost is in the clay and what not? I'd just want to be able to make like a 14-16" pizza I think.

scott123 · October 17, 2011, 04:45:03 PM

Harold, if you want to tinker with an LBE, by all means, tinker, but not a 'lot' of people make Neapolitan on an LBE, and, of the two forums that have succeeded, it took months to achieve the task. The last attempt was by member Pizzablogger. He's one of the smartest members on the forum and it took him over a year to master Neapolitan on the LBE. If you're willing to wait on Neapolitan pizza until you've got the right equipment, you can be eating better than Cafe Milano pies in 2 weeks.

Hdale85 · October 17, 2011, 05:57:29 PM

Yeah I'm not in a rush to try something beyond my skill. For now I just want good pizza

johnamus · November 20, 2011, 01:33:46 PM

Nice work denrayr! Thanks for documenting the process. I've uploaded your photos to the forum in case something happens to photobucket or your account in the future.

Quote from: denrayr on September 21, 2011, 08:19:13 PM
Well I finally pulled the trigger on installing my turbo switch. Here is a guide on how I did it.

First I removed the control console access panel.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0343.jpg

Next I located the temp sensor wires. Usually the wires are the same color and placed next to each other on a molex plug.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0344.jpg

Most ovens use a standard RTD1000 sensor. Some older ovens used a different style sensor. Before going to the trouble to install your switch, you might want to verify your oven has the correct style sensor. An RTD1000 will read between 1080 and 1100 ohms at room temperature.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0346.jpg

I wanted the cleanest install possible. I decided to pull the wires out of the connector and make my connections there. I carefully pried the release tabs inside the connector and pulled the wires out.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0347.jpg

The switch is just a basic single pole switch. I soldered a length of high temp rated wire to each side.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0349.jpg

I soldered one of the high temp wires directly to one of the sensor wires. Next I soldered the other high temp wire to the 10k ohm resister and the resister to the other sensor wire.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0350.jpg

I reinstalled the wires back into the molex plug and plugged it back into the control board.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0351.jpg

Last, I mounted the switch and reinstalled the access panel.

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0352.jpg

After an hour preheat with the oven set to 405, my probe in the oven is reading 603

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0353.jpg

And the stone is reading 675

http://i198.photobucket.com/albums/aa220/beefjerkymw/IMAG0354.jpg

I haven't actually made a pizza yet, but I will post back with the results as soon as I do.

EDIT: I guess the forum doesn't allow embedding images so i changed them to direct links.

EDIT #2: As I stated in a previous post, it doesn't matter whether your oven is gas or electric. They use the same temp sensors. My oven happens to be gas.