New guy with smoke and heat question...

[NYC]

Re: New guy with smoke and heat question...

Entire flue is 4" ID and manufacturer supplied.

[david s]

Re: New guy with smoke and heat question...

If you explain that the oven is unusable in the present configuration, they should replace it with an 8" flue, but will you have room to install the wider pipe?

[lwood]

Re: New guy with smoke and heat question...

NYC, the hole in the top of the dome is a show-stopper. The 4" flue could be replaced easily enough, if it were in the right place. Who ever built this oven for you, obviously never made it work. There is no way you will ever get it up to 700F to cook pizza. A exhaust fan will just pull the heat out of the oven. Bring the guy back and ask him to make it work or....just rebuild.

[NYC]

Re: New guy with smoke and heat question...

That's what I was afraid of. You buy a prefab kit to take the guesswork out of it and it turns out to be all wrong. What a major disappointment.

[shuboyje]

Re: New guy with smoke and heat question...

You might be interested in this link:

The Big Guy! Precast Barrel oven

Personally I would open the enclosure back up, fill the current vent with castable refratory, install an entry and a proper 8" flu, and then going after the manufacturer to cover the cost. They supplied the whole flu, so they knew the application and should have known you would have smoke issues, this is glaring issue with this oven.

[shuboyje]

Re: New guy with smoke and heat question...

Maybe I should look at a link again before posting it. If your oven is indeed the same model there may be some hope. That thread shows the flu opening insert in a larger square opening. If you opened up that square you could probably run a masonry chimney that would do the trick using square clay flue liners. That wouldn't fix the other issues but it would fix the smoke problem. Outside the smoke problem and huge wood consumption this oven does work according to the user in the other thread.

[NYC]

Re: New guy with smoke and heat question...

Yes that is my exact oven make and model.

[david s]

Re: New guy with smoke and heat question...

If you explain that the oven is unusable in the present configuration, they should replace it with an 8" flue, but will you have room to install the wider pipe?

Having had experience in building both updraft kilns and ovens I have found that they work quite adequately. They draw beautifully, much better than a crossdraft (FB Pompeii style) provided the flue is an adequate diameter. It is the column of rising hot air that gives the flue its power and a smaller restriction at the bottom is not as important as the total volume in the flue itself. A great advantage of the updraft design is that you don't have a deep entry to have to work past when putting stuff in and out of the oven. There were a number of updraft ovens at Pompeii (usually smaller) The downside is that they do use a bit more fuel. You can still achieve pizza cooking temps. with ease and if you have a system of shutting the flue you can also do plenty of retained heat cooking.

[DrakeRemoray]

Re: New guy with smoke and heat question...

Before you worry too much about retained heat cooking or pizza temps, we should ask about insulation. Do you know if they put insulation directly under the floor of the oven and over the dome? If not, I would focus on knocking down your chimney (sorry) and putting in an 8" flue as recommended. You will be able to cook pizza but may have trouble getting to 700 degrees without the proper insulation and with that vent(less) design.

If the oven is properly insulated underneath and in the dome, it is probably worth the effort to knock down the existing chimney (sorry again) seal up your existing flue hole then build out a vent and landing in front of the existing oven. Then put in a properly sized (8") flue on that and angle the chimney back so it goes out the same hole in the roof.

That said, if you let the oven dry more with smaller fires, you will probably find that it only smokes for the first 10 minutes or so once it is properly dry...

Do tell us about the insulation though...

Sorry for your troubles.

[NYC]

Re: New guy with smoke and heat question...

The oven "kit" has I believe a 3" thick rebar reinforced high heat concrete shell and the floor has the same type of slab underneath the firebrick for a total of about 5-6". The dome has just the natural stone cemented to it with high heat mortar. I shot the dome with an IR during use which only goes up to 560 deg and the dome was def higher. The floor would go to about 500-550 in some spots and higher in the spot directly under the fire. The outside stone on top of the dome was at about 140deg as was the outside part of the stone on the chimney stack just above the dome.

[brickie in oz]

Re: New guy with smoke and heat question...

Sounds like you have been dealt a dud with no insulation.

The outside of my oven gets 10 degrees above ambient temperature when its 600c inside.

[Tscarborough]

Re: New guy with smoke and heat question...

I know you do not want to hear this, but that is simply a poor design for an oven, especially one that is in a covered area. The chimney vents directly from the firing area, the vent is too small, and it appears to be under insulated.

As a free-standing patio oven it may work passably well, but it is unsuitable for your application, and I would never recommend that design or oven to anyone.

To fix it, block the existing vent, build a proper throat and vent on the current face of the oven, and double elbow the flue back to the existing roof penetration. Not much to do about the insulation without even more major remodeling.

I would certainly let the manufacturer know of your dis-satisfaction.

[NYC]

Re: New guy with smoke and heat question...

Just to update, manufacturer claims the design works and the 4" flue is to retain heat. I had a fireplace expert come look and waiting on his calculations and ideas. Also communicating with the installer to see what can be done once I hear back from the expert. Such a frustrating thing to deal with.

[brickie in oz]

Re: New guy with smoke and heat question...

and the 4" flue is to retain heat.

That would be a comical statement if it wasnt so serious an issue for you.

Edit: Have you pointed the manufacturer to this forum for them to see how its really done?

[NYC]

Re: New guy with smoke and heat question...

I emailed both the manufacturer and the installer this link and both have confirmed they read it. The installer is open minded to seeing how we can try to correct it and the manufacturer says there are many ways to do an oven and their system works. I'm not doubting them but it isn't working in my application and that is all that matters to me after spending so much on my yard.