A better OAK?

Most of mine is 4 inch PVC. I have an OAK running to my fireplace and woodstove. The OAK transitions to 4in steel pipe several feet from the stove and probably 5 ft from the fireplace. Basically kept the PVC on the opposite side of the masonry openings (hope that makes sense?) I also have a ball valve (large valves) on each to close/open the air. I used this material because I like to over build things with as much quality as I can afford.

Solid 4 inch dryer vent is nice and smooth and makes a great extension for the flexible stuff that comes in the kit. I used that flexible stuff to maneuver around obstacles on my air path and used rigid dryer vent and elbows for the rest to minimize the flow restrictions.

Exactly!

ccmac said:

Most of mine is 4 inch PVC. I have an OAK running to my fireplace and woodstove. The OAK transitions to 4in steel pipe several feet from the stove and probably 5 ft from the fireplace. Basically kept the PVC on the opposite side of the masonry openings (hope that makes sense?) I also have a ball valve (large valves) on each to close/open the air. I used this material because I like to over build things with as much quality as I can afford.

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I like the ball valve idea! You can't shut down these epa stoves if you want or need to. I think the mass of my stove cools down faster than it needs to once the fire is out because the draft is puling air through the stove. In shoulder season, I could see shutting the intake side down after the fire is out to stop that loss. Also, if you had a chimney fire, that could also be a way to slow that down by shutting down the intake side. I want to do an OAK but not thrilled with the idea of drilling a whole in the back of my fireplace...this may be the year though.

Mine was a perfect fit. I spent an hour trying to get elbows to work for me in a tight and very weird spot and I finally gave up and joined the last part with metal flexible pipe.
The choice of using rigid vs flex and the size is dependent upon how long your run is. This air is being drawn in and you want to ensure there is minimal resistance. If you search, you'll find some members here have very long runs that seem to work well so not sure how critical this really is.

metalsped said:

So does this rigid stuff readily fit onto the stove OAK outlet? Do they make 45*, 90* fittings, etc? Or just straight runs and I need to use flex tubing for any turns? Thanks for the ideas

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Yes they make 90º fittings but it is better than that. Each of them is made of 4 separate pieces so each one can become almost any angle of 90º or less.

Oldman47 said:

Yes they make 90º fittings but it is better than that. Each of them is made of 4 separate pieces so each one can become almost any angle of 90º or less.

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Yes, adjustable bends from 0 to 90 degrees. Look in the HVAC area of lowes or home depot. I hope to replumb mine with rigid duct too instead of flex. I just did the same thing with my dryer recently and the improvement in flow is amazing.