Harman Accentra Insert Outside Air Kit Install w/ pics

[LIpelletpig]

With careful thought and input from members of the forum, I've finished the OAK for my accentra. Overall it was not that hard to do. I was against going through the back wall of the chimney and cement. So I went up the chimney and put (2) fresh air vents along with raising the exhaust pipe. PVC pipe is 2" with (2) holes drilled in top SS plate. I used the Harman OEM outside air kit and added the 3" pipe which I picked up from HD. The PVC piping and the paint I actually had so no cost for the outside addition. Overall it set me back $110. It took about 3 hours overall from start to finish. Not sure if the pics are going to look good but I did attach a few for members of the forum who are contiplating the OAK.

 

[LIpelletpig]

For the new owners of Harman Accentra Inserts....

 

[Cincinnati Kid]

Interesting! I went to my local dealer to discuss purchasing an Accentra Insert. When I asked them about an OAK, they replied you don't need one when the insert is being installed in a fireplace.

I was not going to argue with them but then I thought why does Harman recommend an OAK for their inserts as most are installed in a fireplace.

 

[tjnamtiw]

Very good info for any brand insert! Using the two parallel OAK pipes cuts the resistance to 1/4 of it's actual length, so that brings the 'allowable' length within reach of the actual length. Of course, people are going to post on here that using PVC pipe is a no-no and violates code. Personally, I can't see why the manufacturers state that it must be metal since it is just drawing outside air....

 

[Turbo-Quad]

Let me first say, that I know absolutley nothing about AOK, but why would you want to draw air in so close to the exhaust?

 

[Don2222]

Hello

Drawing air in close to the exhaust helps pre heat the fresh air! Our SL550 Heat & Glo fireplace has a double wall flue and the fresh air comes in thru the outer wall!!

Stoves, like boilers, like car engines like warm air for better combustion.


I found cold damp fresh air in my pellet stove on the lowest heat setting causes CAKED ash in the burn pot because of incomplete combustion!

So long warm OAKs work the best on low heat settings in the shoulder seasons!

 

[Trickyrick]

For the new owners of Harman Accentra Inserts....

Wow, Looks like you did everything correctly. You ran your (looks like 4") exhaust all the way up to the cap and you used the flue around your exhaust flex pipe as your air intake.... As long as you do not have mixing in the flue then I can not think of any reason why that should not work.

Sorry it didn't work for you....

 

[Trickyrick]

Hello

Drawing air in close to the exhaust helps pre heat the fresh air! Our SL550 Heat & Glo fireplace has a double wall flue and the fresh air comes in thru the outer wall!!

Stoves, like boilers, like car engines like warm air for better combustion.


I found cold damp fresh air in my pellet stove on the lowest heat setting causes CAKED ash in the burn pot because of incomplete combustion!

So long warm OAKs work the best on low heat settings in the shoulder seasons!

I think the issue is DAMP air used in combustion. Not sure about boilers but Engines of every sort give better performance with COLD air. Now for open Fire Obviously warm air is more efficient but it is less energy to heat cold air directly in an open fire than it is to use warm air for combustion then utilize a heat exchanger to warm the new cold air.

I Really think the issue is DAMP air, as that robs all combustion of efficiency by reducing O2 content.

 

[tjnamtiw]

So, did you run the OAK piping all the way up to the two intakes or just terminate it past the smoke shelf? If you stopped at the smoke shelf, did you seal it off with a plate?

 

[LIpelletpig]

I did not run the 3" pipe up the length of the chimney. I found that probably would be to restrictive in pulling the air. I did plate off the smoke shelf. One thing to note here is YES the air I was pulling was warm. It's the air that's been heated by the exhaust pipe running up the chimney. The draw at the top of the 20' run for the fresh air could barely be felt since it was such a long way to pull air. That might be the reason this set-up didn't work well for me. If you have a clean-out ash well in your fireplace that goes to the outside of the house that might work much better since it's usually a short run like any stand-alone unit would have.

 

[Don2222]

Hello

Yes too long a run for an OAK is not good. My manual recommends not more than 15 feet MAX. How long was your OAK?

Also engines do like cold air when operating at high temperatures because there are more oxygen molecules in cold air but warmer air helps them start up in summer easier. This would equate to running a pellet stove on high. On high the pellet stove exhaust blower is higher and should be pulling in cooler air. I do agree that DAMP fresh air is much more or a problem so a longer run such as 10 - 15 feet may help it dry out but too long a run may also be a problem by not getting enough fresh air.

Tricky stuff, hope all the info here helps.

 

[LIpelletpig]

I only ran the 3" pipe from the back of the stove 3 to 4 feet above the smoke shelf. With inserts the OAK is a tuff decision since the runs are usually long to pull fresh air.

 

[Proud Sub Vet]

Interesting! I went to my local dealer to discuss purchasing an Accentra Insert. When I asked them about an OAK, they replied you don't need one when the insert is being installed in a fireplace.

I was not going to argue with them but then I thought why does Harman recommend an OAK for their inserts as most are installed in a fireplace.

I just ordered the Accentra 52i last weekend! I asked about the OAK too and was told not needed without hesitation. I've been reading all these posts and doing my due dilligence before it's installed during the first week in January so I do have some time. I am leaning towards the OAK!!

 

[SmokeyTheBear]

Metal only please, thank you.

Take it up with the code folks.