To OAK or not to Oak

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I am getting a Harman 52i insert for a central chimney. the chimney guy just left and said I can't do an OAK because the piping to an outside wall was too long. also indicated that I don't need a damper plate as the chimney will be capped/sealed and the pipe insulated. Make sense?
 
I am getting a Harman 52i insert for a central chimney. the chimney guy just left and said I can't do an OAK because the piping to an outside wall was too long. also indicated that I don't need a damper plate as the chimney will be capped/sealed and the pipe insulated. Make sense?
The damper plate that was in the chimney originally?
 
The damper plate that was in the chimney originally?
I have read that once the damper plate is removed, sheet metal is used to cover it and a whole cut in the center for the pipe to pass through... The chimney/installer guy said it wasn't necessary to sheet metal the damper as the chimney cap is sealed and insulated. kind of make sense and will pass local code.
 
I have a thought or an addition for discussion.......
Let me draw you a mental picture, My house is essentially "L" shaped the bottom of the "L" has a basement under (concrete floors, stone wall UN-insulated ceiling or floor of "the first floor") under the latter part of the "L" which is under my kitchen is a crawl space. An opening roughly 3'X3' connects the two spaces.

This crawl space is 16'x16' stone walls no insulation with dirt floor, the center is a trench to crawl in that is probably 4ft deep (4ft from bottom of floor Joice to bottom of trench) and roughly 4ft wide, the remaining area in the crawl space is probably only 2ft from floor Joice to dirt. Most of my water lines are in this crawl space (go figure !) therefore when it is 0* outside I run my boiler once or twice a day to get some heat into the crawl space.

I am considering doing an OAK but pulling air from this space, its cold air and I think it would draw warm air from my basement into the space and maybe keep it a bit warmer....... than I do not have to worry about the thing sucking in my exhaust in the event of some type of wind situation or the wind taking from my OAK or excessive moisture from outside coming in .

My thought is: You're still using air from inside the house....and it has to be replaced by outside air filtering in thru cracks/crevises etc. Sucking combustion air from the crawlspace still lowers the overall pressure of the house. Outside air being higher pressure will find its way in via the path of least resistance,
 
I have read that once the damper plate is removed, sheet metal is used to cover it and a whole cut in the center for the pipe to pass through... The chimney/installer guy said it wasn't necessary to sheet metal the damper as the chimney cap is sealed and insulated. kind of make sense and will pass local code.
Nevermind! the stove dealer gave a great deal on stove, install and piping through chimney. Non insulated pipe that is capped at the top and he will be using a blocker plate at the damper location.
 
I have had my OAK hooked up for 2 years. For the past year I have been trying to wrap my head around the idea. My main question is the convection blower of my stove is pulling room air, therefore pulling cold air from the outside. Since I'm sure the convection blower pulls a lot more CFM than the firebox it kinda makes me think what's the point. I do have a leaky set of french doors close to the stove so that make me rethink me needing it. Oh well, I'll stop thinking now.
 
Just a word of note the colder the air in the stove , the lower the flue temps coming out, so yes the hotter the air in the hotter the air out....more heat across the heat exchanger =more efficiency% Even though colder air may have a better combustion its effect is negligible on giving you more heat output..The OAK is really more for safety so you dont overheat the stove, if the room temp gets too hot, and reduce negative pressure effects in tightly sealed homes. My stove mixes room air with combustion air , so in fact some fresh air gets in the room and gets sucked in the convection blower as well. Its nice to have a bit of fresh air coming in IMHO.
 
I have had my OAK hooked up for 2 years. For the past year I have been trying to wrap my head around the idea. My main question is the convection blower of my stove is pulling room air, therefore pulling cold air from the outside. Since I'm sure the convection blower pulls a lot more CFM than the firebox it kinda makes me think what's the point. I do have a leaky set of french doors close to the stove so that make me rethink me needing it. Oh well, I'll stop thinking now.
Ditto on the leaking French doors - 2 sets...
 
Another reason to use an OAK. The reduced pressure in the house, caused by using house air for combustion, increases the ingress of Radon.
 
But to move the air it has to pull from somewhere. I know my house isn't air tight so I can only assume it will also be pulling cold air inside.
The convection blower recycles room air and does not take air from the OAK.
The combustion blower input is usually directly tied to the OAK so that it uses only outside air for combustion.
 
The convection blower recycles room air and does not take air from the OAK.
The combustion blower input is usually directly tied to the OAK so that it uses only outside air for combustion.

That makes perfect sense for a completely sealed area. In a house with air leaks there is no way for the convection blower to differentiate between recycled room air or air from the outside. So if I unhook my OAK it will be pulling the same room/outside air as my convection fan but at a lower rate, correct?
 
But to move the air it has to pull from somewhere. I know my house isn't air tight so I can only assume it will also be pulling cold air inside.
Its no different than sitting a box fan in your living room. The circulation fan does just that....circulate. No air leaves or enters your house. Pressures don't change.
The combustion fan......on the other hand....takes air from inside your house (without an OAK)....and sends it outside. Thus reducing the pressure inside your house. Outside air being at a higher pressure...filters in wherever it can. With an OAK..outside air goes directly into the stove...and out the exhaust. Thus...no change in pressure and no "makeup" air is needed.
 
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Its no different than sitting a box fan in your living room. The circulation fan does just that....circulate. No air leaves or enters your house. Pressures don't change.
The combustion fan......on the other hand....takes air from inside your house (without an OAK)....and sends it outside. Thus reducing the pressure inside your house. Outside air being at a higher pressure...filters in wherever it can. With an OAK..outside air goes directly into the stove...and out the exhaust. Thus...no change in pressure and no "makeup" air is needed.
Thank you...I was getting frustrated
 
Another reason to use an OAK. The reduced pressure in the house, caused by using house air for combustion, increases the ingress of Radon.
Radon is only an issue if ur ontop of a landfill or farm runoff.
 
That makes perfect sense for a completely sealed area. In a house with air leaks there is no way for the convection blower to differentiate between recycled room air or air from the outside. So if I unhook my OAK it will be pulling the same room/outside air as my convection fan but at a lower rate, correct?
Yes, that is correct, but what is your point?
 
Another reason to use an OAK. The reduced pressure in the house, caused by using house air for combustion, increases the ingress of Radon.


Its much much easier to pull makeup air from your leaky windows and sill which would not have radon. The radon is coming from your below grade concrete seeping in slowly from the soil. But I guess it would come in a little more from the concrete walls.
 
Can someone point me in the direction of an explaination of the OAK system? Who makes it, How it's installed, what units it works best on ect...?
Thanks
 
Its much much easier to pull makeup air from your leaky windows and sill which would not have radon. The radon is coming from your below grade concrete seeping in slowly from the soil. But I guess it would come in a little more from the concrete walls.
The air will come from wherever it wants to come from. If the pressure in the house is reduced, more radon will seep in through cracks and porosity of the basement. A house with positive pressure (near impossible to achive) would have very little elevation of Radon above the local normal levels outdoors.
 
Can someone point me in the direction of an explaination of the OAK system? Who makes it, How it's installed, what units it works best on ect...?
Thanks

Have you read this thread from the beginning??? The theory has been explained ad nauseam.
 
Can someone point me in the direction of an explaination of the OAK system? Who makes it, How it's installed

It should be offered as an option (or may be required) with the stove and described in your manual.
 
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