Best routing option for OAK on new install Harman P61

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OnTheWay

New Member
Sep 24, 2023
5
New Hampshire
Hey again,

After the recommendations received from this group, we put a new Harman P61 on order and it is scheduled to be installed in about a week. We are excited to have the stove now that overnight temps have fallen below freezing and it daytime highs are 40s - low 50s.

I have been researching outside air kits (OAK) and they are heavily recommended by Harman for all installations. Our house is not super air tight (1988 colonial with original windows) but we do have a spray foamed attic. I also don't want cold air being pulled into the house just so I can send hot air up the chimney. I brought up the OAK idea to my supplier/installer and he said they could do it if I wanted but they typically do not do OAKs in our part of New England unless it is required, like for a mobile home. I think some of his reasoning was quite faulty but won't get into it here.

My question is what is the best way to route the OAK given my stove will not be on an outside wall. We have a large central chimney with three flues for the stove, fireplace, and boiler.

Option 1. OAK goes up the chimney next to the new liner for the exhaust. It is about a 20-25 foot run. There should be space as that section of chimney is 9x12 clay lined.

Option 2. Run OAK down the chimney into the currently unfinished basement, then along the ceiling to the outside wall (about 6' feet) and drill 3" hole through the concrete. This would still be about 3 feet above the ground.

What would the group recommend? I see benefits and tradeoffs to each option and please let me know if missed an option completely!

Thanks for your help!

Exterior Chimney.jpg Stove Pad.jpg Possible OAK Location.jpg
 
When they installed my P61a in January 2014, they didn't run an OAK even though it is highly recommended. I did a self install OAK fall of 2014.

My vote would be in the chimney if you can.
 
When they installed my P61a in January 2014, they didn't run an OAK even though it is highly recommended. I did a self install OAK fall of 2014.

My vote would be in the chimney if you can.
Thanks for the response, neighbor. I agree that up the chimney seems like the least amount of work. I am sure they can modify the heights so that exhaust gases don't get pulled back into the OAK.
 
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