OAK: Does it cause burn pot cooling?

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

lessoil

Minister of Fire
May 31, 2008
731
Western Maine
Just wondering if this could happen. Would you require fewer pellets
to attain the same heat output by using inside air?
Or, would the air that you pull in through leaks in the house negate this?
 
lessoil said:
Just wondering if this could happen. Would you require fewer pellets
to attain the same heat output by using inside air?
Or, would the air that you pull in through leaks in the house negate this?

Yes, an OAK does bring in cooler air and damper air. However it does keep the house much more comfortable than not having one and bring air in from all the cracks! Simply because when it pulls cooler outside air across your body and the room you are in, it feels cooler to you and makes the room cooler!

Cooler air has more oxygen so it burns quite well. However the damp air from the shoulder seasons seems to be more of an issue when burning the pellet stove on a low feed rate. The dampness can make the pellets stick and clog in the burn pot. You can adjust the air and feed rate to compensate. Some stoves like the Avalon and Lopi have an opening in the OAK plenum inside the stove to mix the outside air with heated inside stove air to rectify this dampness issue.

The best solution I have seen is using the SelKirk venting system that brings in the outside air thru a double wall in the pellet flue vent. This system dries out the OAK air and warms it up also. That is the way to go if possible!!!

Hope that answers your question.
 

Attachments

  • SelKirkDVwithOAK.jpg
    SelKirkDVwithOAK.jpg
    42 KB · Views: 516
Cool air takes more heat to warm up, so less heat for the house, less efficient. If you preheat the out side air like taking waste heat form the vent that's the most efficient way. Taking warm inside air still requires heating the air displaced by the pellet stove, from out side.
 
I don't even have one installed yet and I have to say go with an OAK whenever possible. I will hopefully have one installed and ready before the stove gets fired up this year. I can feel drafts with my unit running that are not even noticeable when it is off.
 
Having been using pellet heat for years, I will add this tid bit.

Back years ago when we installed our first stove, we installed the OAK as per the instructions.

Upon installing two other stoves we left the OAK off the to do list.

Our house has a "fresh air blend vent device" in the main heating systems air handler and is basically open to a roof vent all the time.

After running the two stoves without the OAK, we noticed that cooking odors and other stale smells were not present.

The influx of fresh outside air in small amounts clears the air inside of these unwanted odors.

Now if we lived in an area that sees very COLD winter temps (BRRRRRRRR -20f OR SO) I might rethink this plan.

A house thats sealed up tight tends to trap more nasty odors and allergens than one that sees a regular changing of the air.


Now, using a stove without an OAK in a house that does not have a way to let fresh air inside easily can cause issues..


Just my 2 cents worth.

Snowy
 
Hello

So the key to a house with no drafts is the Big 4" oil boiler OAK and little 2" pellet stove OAK in my case.

Our heating appliances are both in the basement so they would not help with cooking odors. We have an exhaust fan over the stove for that.

See Pic below of Big OAK & Little OAK !!!
 

Attachments

  • BigOAKLittleOAKsc.jpg
    BigOAKLittleOAKsc.jpg
    25.6 KB · Views: 272
Don2222 said:
lessoil said:
Just wondering if this could happen. Would you require fewer pellets
to attain the same heat output by using inside air?
Or, would the air that you pull in through leaks in the house negate this?

Yes, an OAK does bring in cooler air and damper air. However it does keep the house much more comfortable than not having one and bring air in from all the cracks! Simply because when it pulls cooler outside air across your body and the room you are in, it feels cooler to you and makes the room cooler!

Cooler air has more oxygen so it burns quite well. However the damp air from the shoulder seasons seems to be more of an issue when burning the pellet stove on a low feed rate. The dampness can make the pellets stick and clog in the burn pot. You can adjust the air and feed rate to compensate. Some stoves like the Avalon and Lopi have an opening in the OAK plenum inside the stove to mix the outside air with heated inside stove air to rectify this dampness issue.

The best solution I have seen is using the SelKirk venting system that brings in the outside air thru a double wall in the pellet flue vent. This system dries out the OAK air and warms it up also. That is the way to go if possible!!!

Hope that answers your question.

+1.. I like the Selkirk Direct Temp. It's bulkier than than normal pellet pipe, but it offers great benefit in only cutting 1 hole during install, and the preheating of the incoming air: which prevents the condensation drip off which happens with most fresh air pipes during cold weather. The 4" dia vent is easier to clean, as well.
 
Don2222 said:
lessoil said:
Just wondering if this could happen. Would you require fewer pellets
to attain the same heat output by using inside air?
Or, would the air that you pull in through leaks in the house negate this?

Yes, an OAK does bring in cooler air and damper air. However it does keep the house much more comfortable than not having one and bring air in from all the cracks! Simply because when it pulls cooler outside air across your body and the room you are in, it feels cooler to you and makes the room cooler!

Cooler air has more oxygen so it burns quite well. However the damp air from the shoulder seasons seems to be more of an issue when burning the pellet stove on a low feed rate. The dampness can make the pellets stick and clog in the burn pot. You can adjust the air and feed rate to compensate. Some stoves like the Avalon and Lopi have an opening in the OAK plenum inside the stove to mix the outside air with heated inside stove air to rectify this dampness issue.

The best solution I have seen is using the SelKirk venting system that brings in the outside air thru a double wall in the pellet flue vent. This system dries out the OAK air and warms it up also. That is the way to go if possible!!!

Hope that answers your question.

You can also drill out a 5/8" hole in the air intake snout on the stove to "mix" room air and OA
 
Hoverfly said:
Cool air takes more heat to warm up, so less heat for the house, less efficient. If you preheat the out side air like taking waste heat form the vent that's the most efficient way. Taking warm inside air still requires heating the air displaced by the pellet stove, from out side.

You are talking about a temp differential which is so small...and it would only be evident at start up or on a very low temp burn.
 
I have to wonder about this from a whole different angle. With car engines the cooler the air coming in the more complete the combustion. That is where intake pre-coolers came into play. Would it not be the same for a pellet stove?

Heck in my dinosaur days of drag racing we piled ice on the top of the carb intake just before going up to the line to race.
 
Status
Not open for further replies.