Re: Welcome to the new Forno Bravo Forum

[dmun]

Re: Welcome to the new Forno Bravo Forum

I guess I will try leaving a window open for more air but I think the problem could be the flue is too short.

Many outdoor ovens only have the shortest stub of a chimney, and after the first puff of smoke upon startup they draw just fine.

I think your oven is starved for air. Do you have a Carbon Monoxide detector? This is not an idle question...

[Jeanne]

Re: Welcome to the new Forno Bravo Forum

My vent and flue are in the front (located in what is called the breach). It slants back and then runs straight up and out of the roof of the enclosure that was built around the oven. There are pictures of it on the Photos under"" Vents and Chimneys. I do not have a carbon monoxide detector in my kitchen but one in my mud room near my garage door. Should I put one in my kitchen also. Now I am getting worried.

[jengineer]

Re: Welcome to the new Forno Bravo Forum

No one has touch the two comments:
Also my oven does not get totally white inside after 2 hours of heating.

How much insulation do you have? You should have a subtantial amount either vermiculite concrete mix or 2 inches of insulating board (not the fluffy stuff) under the floor of the oven. In addition you should either have commercial grade insulation (not the stuff you get at Home Despot) 2 inches surrounding the oven or a heavy load of loose vermiculite/perlite surrounding the oven. Without proper insulation it will take a long time and a lot of wood to get the oven white.

Another item of note would be extra cladding (concrete or fire clay) to add mass to the oven which will be used if the purpose of the oven is for extended cooking times such as bread making.

je

[Les]

Re: Welcome to the new Forno Bravo Forum

je,

I went to white on my first fire and I didn't have a spec of insulation on it. Didn't take that long as I recall but I was drinking a lot of wine. I think the clue here (and David mentioned it) is drawing air. She mentions that she can throw a log (seasoned hardwood) onto the fire and get black smoke in the room. That sounds to me like it isn't drafting worth a damn.

JMO,

Les...

[AnnieMacD]

Re: Welcome to the new Forno Bravo Forum

Jeanne,

I agree with Les above. I think your problem is lack of drawing air. Do you have access to a bellows? I had similar issues to you when my oven was new. However, I now have had many, many firings and, consequently, lots of experience in getting the fire to perform! I bought a cheap hand bellows which helps tremendously when the fire is at the front of the oven - I can really get the fire going with it. I also prop up my door on a small block of wood or brick - in front of the chimney opening - which creates a draught. When I push the fire back to the mid portion of the oven and add more wood, I also need to add more kindling as the fire tends to black out a bit and produce quite a bit more smoke - the whitening roof often blackens up a bit then too. When I get the fire to the back of the oven it is then usually roaring and very hot and the whole roof whitens. Maybe you are moving the fire back too quickly?? What size is your oven? I have the Casa 160 and it takes about 1.5 hrs to get to pizza heat.

If it's any help to you, I found that it's only with experience that you will become one with your oven - there is quite a steep learning curve and then one glorious day it will all come together and you will have the most wonderful fire imaginable.

There is a forum topic by Frances on smoke reduction that may help too:
http://www.fornobravo.com/forum/f9/s...ucer-5190.html

Annie

[sarah h]

Re: Welcome to the new Forno Bravo Forum

My vent and flue are in the front (located in what is called the breach). It slants back ...

Jeanne, it's hard to tell from your photos but it looks like there may be as much as a 90 degree bend in your flue pipe - and that's just the portion at the back, where it comes out and then goes up - is that so?

Perhaps that's the reason it's not drawing well - anyone more knowledgeable care to comment?

Sarah

[Mitchamus]

Re: Welcome to the new Forno Bravo Forum

I think it's definitely oxygen starvation. IMHO..

A rule of thumb to get effective airflow circulation in any kind of system, the exhaust outlet needs to be around 2.6 times larger than the inlet hole.

Obviously though, you fire requires a certain amount more air to burn as well.

I might also get your chimney swept as a precaution, it might be stuck with soot after all the poor combustion..


cheers,
Mitch.

P.S. - do you have a chimney cap on? it might be dew running down the inside of your chimney.

[AnnieMacD]

Re: Welcome to the new Forno Bravo Forum

Jeanne, Would you post a link to your pics - I can't find them?
Thanks,
Annie

[Jeanne]

Re: Welcome to the new Forno Bravo Forum

Here is the picture. It is under Photo Gallery...Vent and Chimney.. I fired up the oven yesterday. I left the window open about 4 inches. It is directly next to the oven. I did get less smoke actually ony 2 times during the process each time when I added wood and the fire got large ( hit the ceiling ). It took about 3 hours for the whole inside to turn completely white I'm guessing because I kept the fire at a minimum adding wood slowly and using kindleing to keep a constant flame. If you look at the picture it is decieving. The flue is at a 35 degree angle where it conects to the pipe that goes straight up.Then I have the exhaust fan on top of that. ..not to mention I had the fan on high during the whole firing and baking time. I manage to bake 4 loave s of bread that came out nice but the occasional smoke in the kitchen is not good. This morning I contacted the builder who put in the oven and hopefully he can help. someone told me to call an HVAC person to analyze the flue design. All the ovens I see on line the flue goes straight up. Because the oven is in my kitchen wall ( the front opening flush with the wall) my builder had to extend the flue away from the house if you understand what I mean. The other variable that could be effecting this is it has been very cold here 20 dergrees. I have no problem keeping the fire going especially when the oven has been firing for 2 hours. My wood is so well seasoned that it lights fast. it is the beginning stages of the firing when the flames get large that the smoke comes back through the front door. The oven is also very well insulated with plenty of vermiculite as well as a blanket. I know that part of the process was done correctly. Thanks to all of you for taking the time to help me. Yes I love this oven and I am sure we will get it right. Not only did it cost a lot but the pizza is too good to not have it work as easy as everyone says.

Chow,

Jeanne




PhotoPlog - Vent and Chimney

[Mitchamus]

Re: Welcome to the new Forno Bravo Forum

A lot of the pics of ovens I see on here have soot on the front opening arch.

I'm not sure if it's an inherent issue with the vent/chimney design or what.. but I do see it a lot.

Jeanne... silly question - but was it windy at all at the time? it could be something as simple as that...

[dmun]

Re: Welcome to the new Forno Bravo Forum

I'm thinking that there is some sort of serious constriction in your flue somewhere. It might be worth a few bucks to have a chimney sweep come in and put a brush through it, which should go around a thirty degree bend, no problem. If something is pinching up that flue somewhere, that should reveal it.

I don't have photoblog access anymore for some reason. Could someone copy the image locations and paste them in a reply so I could take a look at them?

[Les]

Re: Welcome to the new Forno Bravo Forum

David,

Jeanne only posted 2 pic's - here they are

[dmun]

Re: Welcome to the new Forno Bravo Forum

Hmmm. A couple of observations: That sure looks like a 90 degree bend to me. Code calls for no more than two bends, no steeper than thirty degrees, in a flue. Second, it looks like the chimney outlet is not two feet above anything within 10 feet, although that shouldn't have anything to do with the draw.

I just don't know. That vent, code or not, should draw if nothing is blocking it. Forget about my last suggestion, about getting a chimney sweep brush down it, though.

You say your mason put that flue fan on when he built the oven: Have you tried it without it? Maybe that's the blockage. When you pull it off, you could also look down and see if you see any reflected light through it.

[sarah h]

Re: Welcome to the new Forno Bravo Forum

I'm also thinking that maybe the fan is the problem, causing blockage at times, but perhaps also in preventing the oven from going white - is it possible that it's causing too much of a draw, thus pulling in too much cooler air and sending most of the heat straight up the chimney? Just a thought ... but as David suggests, a good diagnostic would be to remove it and see what happens (still keep the kitchen window cracked open just a bit).

Sarah

[Frances]

Re: Welcome to the new Forno Bravo Forum

Another variable you might try is this:

http://www.fornobravo.com/forum/f9/s...ucer-5190.html

It was very easy to build and has really minimised my smoke issues. And remove the fan and keep the window open - sounds like good advice to me. I'm sure you'll get there in the end, good luck!