Outside Air Kit

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Diabel

Diabel

Minister of Fire
Hearth Supporter
Jan 11, 2008
3,859
Ottawa, ON
I have been using the stove (BK Princess) for about a month now. I am convinced now that the stove needs OAK. Last weekend the stove was out and laundry dryer was going. There was a strong chimney smell at the top of the stairs.
I went downstairs opened the bypass and air, put my hand inside the stove and could feel a strong draft coming down the chimney. To my surprise there was a small piece of charred wood still warm. I did not make anything of it, shut the stove door and left the room. 20 min later I could smell distinctive smoke smell upstairs, went downstairs to see the room hazy with smoke. The little piece of wood started smoldering and due to the dryer running the smoke was being pulled into the room.

Question:

If the OAK was installed, would it prevent this occurrence? And more importantly, why? If the house is supper tight, the dryer or bathroom fan will still pull outside air from somewhere and in this case from the least resistant cavity...the OAK or he chimney. Am I missing something here?
 
Diabel said:
I have been using the stove (BK Princess) for about a month now. I am convinced now that the stove needs OAK. Last weekend the stove was out and laundry dryer was going. There was a strong chimney smell at the top of the stairs.
I went downstairs opened the bypass and air, put my hand inside the stove and could feel a strong draft coming down the chimney. To my surprise there was a small piece of charred wood still warm. I did not make anything of it, shut the stove door and left the room. 20 min later I could smell distinctive smoke smell upstairs, went downstairs to see the room hazy with smoke. The little piece of wood started smoldering and due to the dryer running the smoke was being pulled into the room.

Question:

If the OAK was installed, would it prevent this occurrence? And more importantly, why? If the house is supper tight, the dryer or bathroom fan will still pull outside air from somewhere and in this case from the least resistant cavity...the OAK or he chimney. Am I missing something here?
Click to expand...

Most newer homes have by code a fresh air intake into the cold air return of the furnace, this will draw air for your dryer, bathroom fans etc. Having a OAK for your stove is just extra insurance that your stove is getting the air it needs.
 
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Did you close the bypass before you shut the door? Just curious.
 
Ludlow said:
Did you close the bypass before you shut the door? Just curious.
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The bypass was closed when I was getting the chimney smell. Once I opened the bypass and the wood started to smolder I was getting a strong wood smoke smell
 
Did you check the furnace cold air return to see if it had it's own air supply, like I suggested? This would be an unrestricted air supply from outdoors.
 
I do not have a furnace, only an air source heat pump, electric hot water tank and HRV. The only major air draw is the clothes dryer, hood fan and bathroom fans. They all have those little trap flaps, where the chimney and the OAK does not. Hence my question.
 
Sodbuster said:
Did you check the furnace cold air return to see if it had it's own air supply, like I suggested? This would be an unrestricted air supply from outdoors.
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That is the biggest joke ever, the fresh air into the return. Furnaces have a limited heat rise and doing what you say, one would need to oversize their equipment tremendously. All the Energy Dept mandates go right out the window doing that. If using a condensing furnace, which have a lower heat rise than the 80% and less equipment of the past, your supply side temps would be uncomfortably cold. Employing an air to air heat exchanger would be the only way that would work. Does an air to air heat exchanger qualify as unrestricted?
 
Ludlow said:
That is the biggest joke ever, the fresh air into the return. Furnaces have a limited heat rise and doing what you say, one would need to oversize their equipment tremendously. All the Energy Dept mandates go right out the window doing that. If using a condensing furnace, which have a lower heat rise than the 80% and less equipment of the past, your supply side temps would be uncomfortably cold. Employing an air to air heat exchanger would be the only way that would work. Does an air to air heat exchanger qualify as unrestricted?
Click to expand...

I'm not qualified to answer that, but it sounds like you are. He already has a HRV, so what's your suggestion?
 
Sodbuster said:
I'm not qualified to answer that, but it sounds like you are. He already has a HRV, so what's your suggestion?
Click to expand...

You mentioned the word unrestricted. Im wondering if a HRV is considered unrestricted? That is a good question. I truly dont know.
 
The HRV is supposedly balanced . But if I make another cavity in the house envelope, would this not make the dryer want to pull more air from the stove area?
 
Diabel said:
The HRV is supposedly balanced . But if I make another cavity in the house envelope, would this not make the dryer want to pull more air from the stove area?
Click to expand...
Not sure what you ended up doing with your OAK, but until you get it figured out I would strongly recommend several CO detectors be implemented ASAP.
IMHO I think an OAK would help your situation with the dryer. The dryer is drawing combustion gases out of your stove during low burn times (end of fire) and that is the "smoke" you are seeing in the house. An OAK may isolate the dryers ability to draw those gases out of the stove via the air inlet.

http://www.chimneysweeponline.com/hooa3.htm
 
I put an OAK on our cabin stove and am so glad I did. I can run the 100K BTU oil furnace that is 9 feet away and it has zero effect on the stove. What I cant do is open the stove door when the furnace is running. I ran a test just to see, but in real use only set the furnace to come on when the stove burns down and the temp falls in the cabin to around 60 degrees. That would happen around 3 am or if we are out hunting so the door wouldnt be open then anyway. Otherwise the burn in the stove has zero reaction when the oil burner kicks on, and oil burners pump a lot of air out the flue with the blower in the burner head. OAK's really work. Then again mine is direct connect. Some stoves are passive and that might not work as well in this case.

Plus, the bedrooms are nice and warm and no drafts through the windows, etc.
 
Thanks for the input.

I will try to work without it this winter. But I have a feeling one will be installed come next fall.
 
Diabel said:
Thanks for the input.

I will try to work without it this winter. But I have a feeling one will be installed come next fall.
Click to expand...

I had similar problems with my old install and on my new one the oak solved my problem. Your house also sounds like it needs a source of make up air. Every house and area handle this a little bit differently. Here we use a 4" fresh air supply to the return plenum on the furnace, works just fine but we live in a fairly moderate climate.
 
Ludlow said:
That is the biggest joke ever, the fresh air into the return. Furnaces have a limited heat rise and doing what you say, one would need to oversize their equipment tremendously. All the Energy Dept mandates go right out the window doing that. If using a condensing furnace, which have a lower heat rise than the 80% and less equipment of the past, your supply side temps would be uncomfortably cold. Employing an air to air heat exchanger would be the only way that would work. Does an air to air heat exchanger qualify as unrestricted?
Click to expand...

I was under the impression that the supply air connection for most fuel burning appliances is for the COMBUSTION chamber air only....Am I wrong??? This would mean that MORE already warm conditioned air in your house gets to STAY inside. And the combustion process uses the colder (more oxygen rich) air from outside for its air fuel ratio mixing.
 
Lewisthepilgrim said:
I was under the impression that the supply air connection for most fuel burning appliances is for the COMBUSTION chamber air only....Am I wrong??? This would mean that MORE already warm conditioned air in your house gets to STAY inside. And the combustion process uses the colder (more oxygen rich) air from outside for its air fuel ratio mixing.
Click to expand...

The poster I was replying to was referring to running a fresh air supply into the return air duct. Not the combustion chamber. Two different things.
 
Ludlow, it would be nice if you referred to the poster by name. I had an open air return from the out doors without restriction, basically an open 6" pipe into my cold air return. My basement was around 45 degrees. Had I kept it open, it would have provided combustion air for my wood stove.
 
Sodbuster said:
Ludlow, it would be nice if you referred to the poster by name. I had an open air return from the out doors without restriction, basically an open 6" pipe into my cold air return. My basement was around 45 degrees. Had I kept it open, it would have provided combustion air for my wood stove.
Click to expand...

I am surprised your furnace could make heat if that was the case. The use of an ERV is needed in that intake.


Sodbuster said:
My basement was around 45 degrees.
Click to expand...

No kidding. Why would you want basically an open window in your basement? Pipe an OAK to the stove.
 
Ludlow said:
I am surprised your furnace could make heat if that was the case. The use of an ERV is needed in that intake.




No kidding. Why would you want basically an open window in your basement? Pipe an OAK to the stove.
Click to expand...

It's a flawed system but was very cheap so we saw lots of this set up around here. Most furnaces in older homes are oversized so they have no problem heating a little extra outside air.
 
Ludlow said:
I am surprised your furnace could make heat if that was the case. The use of an ERV is needed in that intake.




No kidding. Why would you want basically an open window in your basement? Pipe an OAK to the stove.
Click to expand...

Our furnace was oversized as well, when it was replaced recently they dropped it from 100K down to 80k because I had disconnected the fresh air system. We bought the house used, but it was my understanding that it was code at the time, to have them installed. I agree dumb idea.
 
vwmike said:
It's a flawed system but was very cheap so we saw lots of this set up around here. Most furnaces in older homes are oversized so they have no problem heating a little extra outside air.
Click to expand...

It just cracks me up how the big push to make houses tight and then they go and do something like having an open hole in the envelope like that. When the furnace isnt running, the cold air will pour in the ductwork and flow out the basement registers. Then a cold basement makes cold floors upstairs. I know they did it. It just doesnt work very well with the condensing furnaces that are right sized for the house because they are designed to run more often but at a lower supply side temperature. The rationale was to maintain more stable indoor air temps I suppose. Now they employ ERV's which makes it better they say.
 
You are saying that when my HRV is not running, cold air is being sucked into the tight house envelope from both ends?
 
Diabel said:
You are saying that when my HRV is not running, cold air is being sucked into the tight house envelope from both ends?
Click to expand...

I meant when you have a direct connection with no HRV and the furnace isnt running. Those ERV's have a flapper in them so they dont pour air into the envelope when off.
 
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Ludlow said:
I meant when you have a direct connection with no HRV and the furnace isnt running. Those ERV's have a flapper in them so they dont pour air into the envelope when off.
Click to expand...

Ludlow, here's whats left of mine, a 6" insulated flex duct was hooked to this stub, and ran to an outside vent with no flapper, the cold air streaming in was ridiculous, especially with the wood stove going, and a north wind.
 

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Ludlow said:
It just cracks me up how the big push to make houses tight and then they go and do something like having an open hole in the envelope like that. When the furnace isnt running, the cold air will pour in the ductwork and flow out the basement registers. Then a cold basement makes cold floors upstairs. I know they did it. It just doesnt work very well with the condensing furnaces that are right sized for the house because they are designed to run more often but at a lower supply side temperature. The rationale was to maintain more stable indoor air temps I suppose. Now they employ ERV's which makes it better they say.
Click to expand...

Oh for sure things have changed a lot for the better, they try and tell you it’s about controlling where the air leaks in not elimanting it all together.... the better builders have used hrvs for 20 years or more here.
 
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