Author Topic: Floor losing heat (Read 1580 times)

rumper · « **on:** October 16, 2012, 10:08:20 PM »

I have "the Don" commercial oven found here
http://www.woodfiredovens.com.au/products/commercial-pre-built/
which is trailer mounted. I cater and and cook up to 90 pizzas but usually only about 40 - 50. The problem I have is I start with the floor around 750 and it drops to about 520 after about 30 pizzas and they then take too long to cook on the bottom. Does anyone else have a similar problem losing floor heat or does anyone have any possible solutions. I can give it a break and it will warm up again to about 590 but this isn't practical.

shuboyje · « **Reply #1 on:** October 16, 2012, 10:33:04 PM »

Their website is not very clear. Do you know if the oven floor is insulated?

rumper · « **Reply #2 on:** October 17, 2012, 01:45:29 AM »

Yes it is with a thin layer of insulation it is the same insulation they use on the dome

scott123 · « **Reply #3 on:** October 17, 2012, 06:06:41 AM »

Ken, how thick is the insulation and what kind of insulation is it?

Also, what is the material for the floor and how thick is it?

Lastly, with a 750 hearth, I'm guessing you're not running to big of a fire on the side, correct? The fire on the side is responsible for replenishing the hearth. If it's too small, the hearth can suffer.

breadstoneovens · « **Reply #4 on:** October 17, 2012, 06:29:58 AM »

Quote from: rumper on October 17, 2012, 01:45:29 AM

Yes it is with a thin layer of insulation it is the same insulation they use on the dome

Looking at their website, from what I can tell, they use ceramic fiber blanket for the bottom insulation. Ceramic fiber is good, fiber blanket for the bottom is bad as it compresses under the weight of the oven.
From you describe it sounds like to don't have good bottom insulation.
The best way to fix that would be to add bottom insulation using ceramic fiber boards. If you don't want to take your oven apart, you can place it under the metal stand, if it is accessible, right bellow the floor of the oven. It is not ideal but it would help.
The boards are pretty rigid and can be screwed right bellow the stand.
From the website pictures, if you got their stand, it looks like the stand is made of metal tubing ribs. You could put ceramic fiber blanket in the space between each ribs and then under that, the fiber board.
Do you know where to get the insulation material from?

Antoine

shuboyje · « **Reply #5 on:** October 17, 2012, 09:44:22 AM »

After looking at their site I too concluded they insulate under the dome with blanket, I was hoping I was missing something.

Sounds like lack if floor insulation is your issue

rumper · « **Reply #6 on:** October 17, 2012, 11:51:31 PM »

Thanks Guys they definately insulate with the fibre blanket, I will see how easy it is too get hold of some fibre board and see if i can lift the floorbricks and try to place it underneath (if I do this should I remove the blanket completely?) I live in a small country town so access to material sometimes takes a while.

breadstoneovens · « **Reply #7 on:** October 18, 2012, 09:04:12 AM »

Yes, I would recommend to remove all of the fiber blanket at the bottom as at the end it may even make your floor un-even and result in cracking.
Where do you live?

Antoine

rumper · « **Reply #8 on:** October 18, 2012, 12:03:08 PM »

I am in Broome, Western Australia and I ahve no idea where to get the insulation material from (about to start googling)

breadstoneovens · « **Reply #9 on:** October 18, 2012, 03:43:13 PM »

Yeah, I am bit far to send you anything

If you can't find the ceramic fiber, you can use perlite or vermiculite mixed with cement. Let me know if you resort to that and I will give you the instruction to achieve the desired result.

Antoine

rumper · « **Reply #10 on:** October 18, 2012, 05:45:39 PM »

Thanks Antoine, What thickness board should I be looking at?

rumper · « **Reply #11 on:** December 03, 2012, 01:03:45 AM »

I can't get the board for a while but i could get some more fibre blanket. I thought I would replace the blanket as temporary fix so I did this last week. On Saturday night I fired it up to do 80 pizzas and it performed exactly the same. Is it possible that I did something wrong? The underside of the oven floor reached about 280 which is way too hot.

breadstoneovens · « **Reply #12 on:** December 03, 2012, 11:40:47 AM »

Quote from: rumper on December 03, 2012, 01:03:45 AM

I can't get the board for a while but i could get some more fibre blanket. I thought I would replace the blanket as temporary fix so I did this last week. On Saturday night I fired it up to do 80 pizzas and it performed exactly the same. Is it possible that I did something wrong? The underside of the oven floor reached about 280 which is way too hot.

Certainly too hot, resulting in heat loss.
Was the fiber blanket put directly under and in contact with the oven floor? How many layer did you put of it?
The problem with the blanket is once it is compressed, there not that much thickness left.
If you could send us some pictures of what you did.

Did you contact the manufacturer to let them know of the problem?

Antoine

rumper · « **Reply #13 on:** December 03, 2012, 08:39:03 PM »

Yes I did contact the manafacturer and that is what he recommended. I placed one layer in the oven and put the fire bricks directly on top which is exactly the same as what I replaced, I might be able to get some 6mm(1/4inch) board locally and thought about putting it under or over the fibre blanket not sure if it is a good idea though?

breadstoneovens · « **Reply #14 on:** December 04, 2012, 10:27:08 PM »

Quote from: rumper on December 03, 2012, 08:39:03 PM

Yes I did contact the manafacturer and that is what he recommended. I placed one layer in the oven and put the fire bricks directly on top which is exactly the same as what I replaced, I might be able to get some 6mm(1/4inch) board locally and thought about putting it under or over the fibre blanket not sure if it is a good idea though?

You need a minimum of 1" of the ceramic fiber boards, 2" would actually be best. Don't use the blanket as is pointless under the oven.
Let me know how that works.

Antoine

rumper · « **Reply #15 on:** December 05, 2012, 12:38:59 AM »

Thanks for your help Antoine, hopefully I will be able to get some board early in the new year and until then I will perservere with what I have. I thought changing the blanket would give 6 months or so reprieve but it appears to have done nothing. I will let you know how it works out.

breadstoneovens · « **Reply #16 on:** December 05, 2012, 01:51:32 PM »

My pleasure. Keep in mind as an alternative you can always poor a slab of insulating vermiculite and cement.

Good luck with the project and keep me posted on the progress.

Antoine

sajata · « **Reply #17 on:** December 15, 2012, 02:25:59 PM »

only being a nube in pizza making but an engineer none the less. If you put insulation between the ribs then put insulation over that, that will retain the heat but it will also heat the metal tubes which will weaken them while heated. i would expect over time "sag" woudl be come an issue. and depending on how much they over engineered it could fail.

rumper · « **Reply #18 on:** April 03, 2013, 01:00:30 AM »

Hi Antoine,

I finally managed to get some ceramis fibre board but I could only get 1" because of thr design of my oven. The floor wouls of sat too high if I went any further, I used it last night for the first time and it appears to have worked a treat. Thanks again for your help.

Ken

breadstoneovens · « **Reply #19 on:** April 03, 2013, 12:19:25 PM »

That is fantastic to hear. 1" makes a big difference as the ceramic fiber material is very efficient.

It was my pleasure to help. Best of luck to you.

P.S.: you should post a few pictures of what you cook when you get a chance

Antoine

Quote from: rumper on April 03, 2013, 01:00:30 AM

Hi Antoine,

I finally managed to get some ceramis fibre board but I could only get 1" because of thr design of my oven. The floor wouls of sat too high if I went any further, I used it last night for the first time and it appears to have worked a treat. Thanks again for your help.

Ken