[pcampbell]

I bought a 26 gauge 4" to 3" reducer with a 90 degree elbow but in the space I have, it sticks out too far. What I need is a very short reducer , or an elbow with reducer built in. Must be metal (not plastic). This is for fresh air supply to a wood stove going 90 degrees immediately behind the wood stove into the hearth. Any suggestions?

This is what I have -it's too long when I add a standard 3" 90.

Black would be nice, but not required.

 

[Bob Sanders]

I hope you're not connecting the intake directly to the stove?

I assume your stove is natural draft? Natural draft relies on the fact that warm air rises. It's okay to terminate your fresh air intake a few feet away from the stove, or at minimum provide a draft hood open to the house air..... that gives the air a chance to mix with the warmer inside your house air before it goes into the stove thereby promoting the 'warm air rises' concept. But if you connect directly to the stove the cool air does not warm up and you risk back drafting.

Whole bunch of other problems as well. Read here:

http://www.woodheat.org/the-outdoor-air-myth-exposed.html

 

[Colbyt]

For a no pressure installation of fresh air you might be able to buy 2 cut them up and fabricate something about 2" shorter.

Or better, buy a 4" cap, cut a 3" hole in it and use a 3" take off.

Either one is a bunch of work.

 

[beenthere]

For a no pressure installation of fresh air you might be able to buy 2 cut them up and fabricate something about 2" shorter.

Or better, buy a 4" cap, cut a 3" hole in it and use a 3" take off.

Either one is a bunch of work.

Yep, 4" cap, cut 3" hole. And dove tail the 3" 90 into it.

 

[Bondo]

Yep, 4" cap, cut 3" hole. And dove tail the 3" 90 into it.

Ayuh,... That's my 1st thought as well,....

 

[pcampbell]

4" cap with hole is not a bad idea. I'll check that out. Thanks!

I've read the woodstove.org stuff. I don't think it necessary addresses very tightly sealed houses.

The connection is a "direct connection" but it is not intended to be an air tight connection. There are holes in the adapter that allow it to also pull air in through the room. It is basically just a connector that allows you to mount a pipe to the stove. And feeds the air where the stove would otherwise pull the air from the room. It is code here in new buildings, and it is being installed in a tight house with a balanced HRV, no clothes dryer exhaust (ventless).

So if you did not have any exhaust fans going, the wood stove would probably work great using room air.

If you had multiple bath fans and range fan going, I think you would not be able to get a proper draft going when starting a fire - they are something like 125CFM each (this is where I would just open a window), BUT the make up air is required for my energy certification, which I've worked hard to get, and this is the final requirement, so I'm going to follow through. I can always remove it later.

(I tried to get the certification without doing the supply air, because of all of the arguments against it... but it didn't slip by the energy guy).

 

[beenthere]

Using room air and allowing the room air to be replaced with outside air, dries out the house.

 

[pcampbell]

I found one from Broan - it's a very short reducer 4" to 3".
Now I have another question. I'm looking for a 3" damper. It doesn't seem that they exist.

Otherwise I'll have cold air coming into the house when I'm not using the wood stove.

 

[Colbyt]

With the open slots it may not be exactly what you waant; http://www.woodmanspartsplus.com/65642/16725/Stove-Pipes/Stove-Pipe-Dampers.html