Damper and door questions

[brokencookie]

All of the doors I have seen look like they close the oven before the vent/transition. Has anyone considered installing a damper in the chimney and putting doors on the outside of the oven, after the vent? I can think of a few advantages to this type of design.
1. controlling heat flow by adjusting the draw of the oven via the damper
2. This design would allow for hinged doors rather than a wedged door.


Any thoughts ?

Thanks
Bruce

[dmun]

Re: Damper and door questions

If the point of the door is to keep heat in for baking, you want to confine the area kept hot to the smallest and best insulated part of the oven, the dome. Most commercial dampers are intentionally leaky, to prevent people from asphyxiating themselves with interior wood stoves.

External hinged doors look fine but they aren't too functional. You might want a fireplace type damper in the flue to keep heat in the house in an inside oven, but I don't think you would use it to regulate anything. When that fire is going, you want to vent it all out the best way possible.

[DrakeRemoray]

Re: Damper and door questions

I agree with Dmun on this. Can't really see any benefit to a Damper, though someone has one...who was that?

[Les]

Re: Damper and door questions

I think it was Luis (AKA arevalo53anos)

Les...

[DrakeRemoray]

Re: Damper and door questions

After some searching here is a thread that discusses dampers. Both Xabia Jim and Marcel have dampers, neither seems to use them...

Drake

[cvdukes]

Re: Damper and door questions

I put a damper in the chimney on my ferro-cement constructed pizza oven. At the time I was building it, I didn't know if the damper would be needed but it was easy enough to add, so I stuck it in there. Having fired the oven up 6-7 times now for cooking, I can't say that the damper has any use. My oven has an internal door that I wedge in the oven for bread baking and an external door to close off the antechamber that feeds to the chimney. My thinking was that I could damper the chimney to reduce the heat with the external door in place, but really it doesn't seem to do anything. Just something else to play with...

[brokencookie]

Re: Damper and door questions

Thanks for the info. All of your input makes sense. I think I will leave out the damper idea. However, I will probably make both an interior and exterior door. I have a really bad cat problem in my area. After a cold night I always have to check the engine compartment for cats before starting the car. Same problem with the house. When winter hits all the mice want to invade the warm house.I can foresee having to check the oven for critters before starting a fire. Hopefully a set of exterior doors will deter them.

Bruce

[dmun]

Re: Damper and door questions

It's true - cats are heat-seeking missiles. Those piles of wood ash look awfully like cat litter.

[jwnorris]

Re: Damper and door questions

<snip> I can foresee having to check the oven for critters before starting a fire. <snip>
Bruce

Why bother, just roast in place for a new taste sensation. Better and fresher than roadkill.

J W

[jeff]

Re: Damper and door questions

Just read your post re cats.
You're a bad bugger JW: gotter lovit.
Luddite Jeff.

[Xabia Jim]

Re: Damper and door questions

My oven chimney did come with a damper and I use it everytime I fire up the oven. I tend to season the oven for a longer period of time so after the fire is going, I tend to set the damper at 1/2 closed. I believe this keeps some more heat inside the oven.

A damper allows you to shut down the oven for baking but you can also cover the chimney with a bucket or wet blanket or something to seal it once you take the fire out. The damper also helps if you want to smoke things. The chickens I recently did were nicely smoked by the 1/2 damper technique.

And with all that soot, you get to see it turn white when it's pizza time

XJ

[arevalo53anos]

Re: Damper and door questions

I am just reading this thread now. Sorry by the delay.
My oven has a chimney damper, that is used when the fire is 'in regime'. The combined use of the damper and door (loosely closed) helps to maintain the flames bright and alive and highest temperature, using little wood.

Luis

[james]

Re: Damper and door questions

This asks an interesting question. When we are firing our ovens, and the fire is breathing in air through the open door, how much air is the fire getting from the vent and chimney?

I tried to kill a fire in an oven that had been build in-correctly, where the door sealed the vent opening, not the oven chamber. The fire continued drawing in air through the vent and chimney and just kept burning. It was a bad design, but it showed how the oven can take air "in" where you thought it would only go "out".

Still, I don't see how a chimney damper gives you more control over airflow than a well-positioned door.

James

[Xabia Jim]

Re: Damper and door questions

James, I don't believe any air is coming from my chimney. That's where the smoke and heat is going. A damper helps you keep the heat in and burn less wood. Open and it can get hotter when you want it.

Having used one for years on woodstoves and fireplaces, you get the fire burning and once it is, you can damper it back. A good fireplace or woodstove is an airtight which takes in primary and secondary air to the fire. You also damper down the air supply at the door, so it's a balancing act. Without the damper you burn much more wood.

Now, I have not used a WFO without a door and chimney. Others may have different experiences.

XJ

[arevalo53anos]

Re: Damper and door questions

I agree with XJ.
Just to clarify a little more, when the chimney has a correct relation respect to the oven dimensions, the flue of hot air and flames is vigorously drawing out and up, do not letting space to air return and forcing the air to enter by the lower part of the landing area.
If the chimney is completely opened, the flue is maximum and hotter and there is more wood consuming.
When the oven temperature is the adequate to your needs, the use of the damper let you to regulate this flue.

Luis