Garden Level Cold Air Intake

[q335r49]

Hey all, I just finished remodeling the nova 2 I've had for a couple of years, I tore out the hearth, drilled a hole through the brick, and laid down some tile. Really chip and joanned it up! I'm looking for some guidance on installing a cold air intake

- This is a basement / garden level install that vents into a masonry chimney
- I'm wondering if there is any point in having a cold air intake. It would potentially just be a 1 foot section of 3' pipe going straight out the back of the stove and through the fireplace cover I made, see pic (plywood + lots of foam in the back .... I do plan on adding some fireproof insulation to that plywood cover and to the fairly low ceiling). I have a liner installed, so I suppose, ideally, the cold air source could be the draft around that liner 30 feet up at the top of the chimney.


- The cover itself feels pretty well sealed, but I imagine I would have to seal the upper pipe hole too (see pic), lest the CAI draw from the room itself rather than through the chimney? Maybe furnace cement? Intuitively I'm not quite sure where the air would come from. Would the majority come from the chimney hole 30 feet up, or would it all basically just come from the much closer gaps around the cover and the pipe hole?


- Is there any point in throwing an elbow on the CAI and running the pipe a few feet up the chimney at all?

Thanks!

 

[EatenByLimestone]

Do you need a cold air intake? If it’s not needed, there may not be a benefit to having one.

 

[q335r49]

Do you need a cold air intake? If it’s not needed, there may not be a benefit to having one.

Hmm there's a good chance I don't. 1968 construction with new windows and that spray wool insulation in the attic? I'd imagine the attic is pretty drafty

 

[begreen]

The outside air supply needs to be at or below the firebox floor level. The risk of having it above that level is with the draft reversing, turning the outside air supply into a chimney. Unfortunately, the stove's documentation is weak in this section.

 

[q335r49]

The outside air supply needs to be at or below the firebox floor level. The risk of having it above that level is with the draft reversing, turning the outside air supply into a chimney. Unfortunately, the stove's documentation is weak in this section.

I mean, it would be basically be below, since it vents straight out or I could elbow it so it is below. Also, the OAK is going straight into a masonry chimney, so even worst case scenario of it turning into a flue wouldn't be a big deal.

 

[begreen]

No, it's not the entry point that matters, it's the ability to reverse draft that is the concern. If there is a outdoor vented crawlspace below the stove then that is an acceptible area to draw the air from. If there is a basment, then it should be ducted to the closest outside wall.

 

[q335r49]

No, it's not the entry point that matters, it's the ability to reverse draft that is the concern. If there is a outdoor vented crawlspace below the stove then that is an acceptible area to draw the air from. If there is a basment, then it should be ducted to the closest outside wall.

The entry point would be below the firebox, since the firebox is on 9" legs. It would draft straight to a masonry chimeny where reverse draft would be of no concern.

 

[stoveliker]

But then it would suck air that enters between the liner and the masonry at the top of the chimney, move that air down in the chimney outside the liner to the stove?
That point (where one gets to free open air, i.e
The top of the chimney if the above is correct) should be at or below the stove.

And yes, reverse draft (i.e. combustion gases) going up outside the liner is an issue - that's why the liner is there. Moreover the pipe from the stove to the chimney is unlikely to be rated for exhaust gases.

 

[q335r49]

But then it would suck air that enters between the liner and the masonry at the top of the chimney, move that air down in the chimney outside the liner to the stove?
That point (where one gets to free open air, i.e
The top of the chimney if the above is correct) should be at or below the stove.

And yes, reverse draft (i.e. combustion gases) going up outside the liner is an issue - that's why the liner is there. Moreover the pipe from the stove to the chimney is unlikely to be rated for exhaust gases.

I'm building it, it WILL be rated for exhaust gases. Does anyone have any actual reasonable input, borne from reasonable expectation and common sense, or is it all going to be hypothetical non issues about 1 in a thousand chances of an exhaust gas going up a perfectly clean chimney around the liner once a year?

 

[stoveliker]

It's code which was made to prevent the house fires that were happening because of wrong installs.

 

[q335r49]

It's code which was made to prevent the house fires that were happening because of wrong installs.

If code told you to jump off a bridge, would you do it? 😉

 

[stoveliker]

Yes, if it would save my life and those living in the home with me. And if I can avoid my insurance weasel out of paying when they have to.

You've been informed. Your life, your choices. I'd suggest to discuss this with those also living in your home, if any. Fair to make them aware of the executive decision being made.

 

[q335r49]

Yes, if it would save my life and those living in the home with me. And if I can avoid my insurance weasel out of paying when they have to.

You've been informed. Your life, your choices. I'd suggest to discuss this with those also living in your home, if any. Fair to make them aware of the executive decision being made.

Thanks. I appreciate the informing, and hereby respectfully choose to ignore it, as well as any future advice from said source, as it is not based on a shred of logic, reasoning, or understanding, but instead only on appeal to authority and chicken little whataboutisms. Thanks for understanding.

 

[begreen]

I'm building it, it WILL be rated for exhaust gases. Does anyone have any actual reasonable input, borne from reasonable expectation and common sense, or is it all going to be hypothetical non issues about 1 in a thousand chances of an exhaust gas going up a perfectly clean chimney around the liner once a year?

Ask the stove manufacturer and insurance agent.

 

[q335r49]

Ask the stove manufacturer and insurance agent.

I'm not wondering whether it's "kosher", because I don't care. This is the safest wood stove steup on the side of the mississippi, despite the pressing concerns about a potential backdraft going up a 3 inch pipe into an empty chimney. I'm wondering if it's needed at all. See original post. I.e,. is it even worth putting in a OAK based on my setup, the various leaks I have, and the state of my house. These aren't questions for a stove manufactuerer or insurance agent, more like questions for those with anecdotal experience with wood stove OAK's in similar situations, aka, a web forum.

 

[begreen]

That's certainly one's privilege, though being a public forum responses are read even years from now. Regardless of pov, we're going to advise the safest way to do this, thinking about the next person that reads the thread too.
Seeing the stove has been burning without an oak for 2 yrs. without concern, seems like there's no need to change. Search on OAK in the main forum, titles only. There are many threads on the topic.

 

[bholler]

I'm building it, it WILL be rated for exhaust gases. Does anyone have any actual reasonable input, borne from reasonable expectation and common sense, or is it all going to be hypothetical non issues about 1 in a thousand chances of an exhaust gas going up a perfectly clean chimney around the liner once a year?

Where will the fresh air actually come from? If you are planning on it coming down through the chimney that will never work properly so don't do it there will be no benefit.

 

[q335r49]

Where will the fresh air actually come from? If you are planning on it coming down through the chimney that will never work properly so don't do it there will be no benefit.

I thought so as well. But why not?

 

[q335r49]

That's certainly one's privilege, though being a public forum responses are read even years from now. Regardless of pov, we're going to advise the safest way to do this, thinking about the next person that reads the thread too.
Seeing the stove has been burning without an oak for 2 yrs. without concern, seems like there's no need to change. Search on OAK in the main forum, titles only. There are many threads on the topic.

I've been burning 2 years with an OAK to the chimney, the chimney sealed with sheet metal. So do both of my neighbors. for maybe the last 20 years. But I haven't done any controlled testing or anything. Maybe I should this time. And the next person who reads this would most certainly be more inclined to follow safe practice if this thread provided any actual reasons as to why on god's green earth an OAK to a chimney would be a safety concern, otherwise he would probably dismiss it as pointless rules lawyering as I do.

Yes there are tons of posts about this, including that one single infamous source that tells you OAK is never needed. There are far less sources that consider the problem of drafting from a chimney, the effects of sealing, and whether relative air intake is linear, proportional, bears no relation to distance, pressure, size of opening of whatever, etc. etc.. I suppose I could google scholar this, find some research papers or whatnot, but I figured someone may have already thought about this question.

 

[bholler]

I thought so as well. But why not?

Because it is a chimney it will pull up and out not down typically