Air intake from outside or not?

[Xena]

Your town inspectors go by the stove manual.
If the manual says it's required, then
it's required in order to pass inspection
afaik. I'm no expert by any means, I'm
just repeating what I've learned here.
Good luck with it.

edit: I would like to add that I exchanged pm's
with Mike from ESW about outside air kits and
he specifically told me not to allow my stove to
draw air from the basement. You may want to send
him a pm to discuss this in depth. Again, much luck
with your new stove.

 

[taperk600]

Just a question...... I see most of you have stoves. I have a boiler. I'm going to guess that the same issues arise with the boilers as with the stoves. If so, the same benefits should be gained from adding the OAK ?

 

[jimcooncat]

Well, if you're pumping air from your cellar, through the firebox, and out the exhaust, you're creating a mild vaccuum inside the house. The pressure of the cold air outside the house will force air inside to make up for it.

With an OAK, you're pumping air from outside, though the firebox, then exhausting it back outside. Pressure stays even. Wind will still force cold air in through the cracks, but you're not actively sucking it into the house.

So sure, a boiler will have the same issues. What gets confusing with a hot air system (most pellet stoves) is that there are two air streams, one for combustion, and one to distribute heat through the house.

The OAK cut down on the drafts immensely. I'm seeing this morning that the amount of BTU's my stove's putting out isn't going to keep up with the cold north wind of last night. Even so, it's more comfortable even at a lower overall temperature. And it's better in that I think I'll be able to pinpoint the problems in my house now that I don't have the artificial pressure differences going on.

So now I'm going back to insulating my cellar, and the other yearly buttoning-up activities I normally do at the start of winter. I'm resigning myself to a one-time click of the oil furnace in the morning, and working it out so the pellet stove will keep up with the rest of the day. Maybe next year I'll be able to replace the oil furnace with a wood stove, and possibly a pellet basket for it.

 

[Drivr]

I have a question about whether an OAK is needed with my install or not. My Englander is in the basement, which is very large (runs the entire length of the house). The guys who installed the stove said the OAK wasn't needed because the basement isn't insulated and it's large enough to have plenty of cold air. They also said it wasn't required by code with the dimensions on the basement. They were very particular about sticking to code on everything else, so I'm inclined to believe them.

Guess I'll have to wait it out and see how the stove performs - I hope to not have to install an OAK because the stove is installed on the interior wall of my 2 family house and windows are across the room.

the thing is your stove probably will work fine but you will be sucking air from inside your home and sending it out your stoves chimney. Most people forget there are 2 different blowers in these things, one circulates the air through the heat exchangers and the other is used to feed the fire. this is the same air you are heating with your pellet stove. so you are heating the air in your basement then turning around and sending it right back our your chimney. on top of that it is also creating a negative atmosphere in your home so it will be pulling in outside air from anywhere it can, around doors, windows, stove, vents, chimneys etc.
I tried what you are doing and finally broke down and installed the OAK and man what a difference it made.

 

[wjlundyjr]

My basement corn stove flat out would not run, until I added OAK. I would get a healthy blaze going and come back a few minutes latter and it would be fizzeled out. Added the OA and the things goes like a blow torch, my OA has a ball valve so I can turn down the air supply.

My new wood stove on the upper level (Ithought for sure I'd need OA) can go like an inferno 24*7 with no OA and is easily controlable with the stoves air controls.. But I do leave the stoves door open awhil until a hot draft is going.

 

[pt0872]

My OAK isnt installed....thinking I'm going to do that this week after reading this.

I put my hand over the intake on the stove and couldnt really feel air being pulled in. Should I
be able to feel the air being sucked in or is it very subtle?

 

[wilbilt]

I have been on the fence about installing an OAK.
My stove uses a single fan, which means a single source for both combustion and heat exchanger air.

If I connect it to the outside, it may burn better and reduce drafts, but then I will be continuously attempting to heat the freezing air from outside instead of the preheated inside air.

BTW, it is a mobile home, but nowhere near airtight. In addition to all of the drafts around the windows and doors, there is an OAK installed at the furnace blower with an automatic damper to allow fresh air replacement.

 

[Xena]

If I connect it to the outside, it may burn better and reduce drafts,
but then I will be continuously attempting to heat the freezing air
from outside instead of the preheated inside air.

That is the idea. The stove is better off using the colder air to run..

I have been on the fence
about installing an OAK. BTW, it is a mobile home...

Please check your stove installation manual, I'm pretty sure outside air
is required for all pellet stove mobile home installations.

 

[wilbilt]

That is the idea. The stove is better off using the colder air to run..

Yes, better to burn, but how about the loss in heating efficiency when it is pushing freezing air through the heat exchanger instead of warm inside air?

Please check your stove installation manual, I'm pretty sure outside air
is required for all pellet stove mobile home installations.

I would love to find an installation manual. The company that built these stoves has been out of business for a long time.

It does state that outside air is required for MH installations under the hopper lid. I don't know how the original OAK would have been configured, but I think I can fabricate one pretty easily.

Like I stated, I have been thinking about it, but I don't want to do it if it means I will be burning twice as much fuel to heat my home.

 

[Xena]

.....how about the loss in heating
efficiency when it is pushing freezing air through the
heat exchanger instead of warm inside air?

It doesn't push freezing air through the heat exchangers.

https://www.hearth.com/econtent/index.php/wiki/burning_pellets_for_newbees

 

[wilbilt]

.....how about the loss in heating
efficiency when it is pushing freezing air through the
heat exchanger instead of warm inside air?

It doesn't push freezing air through the heat exchangers.

This one does. Air enters the rear of the pedestal base, and there is a single fan that pressurizes the interior of the stove and pushes air through both the firebox and the heat exchanger tubes.

If I add an outside air tube to the intake, that air will supply both the fire and the room.

 

[please302]

I too was interested in the outside air kit. I thought that it would be more efficient and wouldn't act as a fireplace by sucking in the cold outside air. I just had the pellet stove installed and the dealer stated that it was not as efficient as all the hype. Actually, due to hot air rising and cold air falling and pressure inside your house you actually need air movement. As hot air rises you need it to force cold air down and back to the stove to circulate the hot air in rooms where it is cold. The "wall" of cold air is difficult to displace if you do not have flow thru the house and that is why it is so important when you decide where to place your stove. I think that it really depends on your house's layout, efficiency and the placement and heat output of your stove.

 

[peirhead]

I think I misread the Quad Castile owners manual as I thought the outside air kit for it provided air to the convection blowers but on careful review it may be on the combustion side...has anybody ever heard of a pellet stove using outside air for the convection blower?

I know there were woodstoves in the early 80s that worked this way. (Heatilator Pressurizer for one)

 

[Scoop]

Just never thought that the stove would be able to draw that much air through the exhaust fans.

my forced hot air furnace is in the basement, and uses indoor air for combustion. The wife often leaves the basement door open, so that she can hear the clothes dryer "buzz" when its finished a load. When the furnace kicks on, that door will close all by itself, with "authority". The knob latches with a firm "ca-THUNK".

You shoud vent the furnace room. Not good that the furnace is creating that much of a negative pressure to close the door. Likely means your furnace is gasping for air with the door closed. Just install a return air wall plate somewhere in the furnace room wall close to the floor so it sucks cold air into the room.

my $.02

 

[wilbilt]

...has anybody ever heard of a pellet stove using outside air for the convection blower?

Yes.
See my crude diagram above.

The pedestal is open at the rear, which is where the air is drawn in. There are holes along the sides at the rear to attach a plate to enclose the back of the pedestal, and a 2" knockout in the base of the stove for an outside air connection from under the floor. I assume the block-off plate would also have a knockout for a through-the-wall outside air connection.

Either way, the fan supplies the air for both combustion and convection with no way to separate the two.

 

[Scoop]

...has anybody ever heard of a pellet stove using outside air for the convection blower?

Yes.
See my crude diagram above.

The pedestal is open at the rear, which is where the air is drawn in. There are holes along the sides at the rear to attach a plate to enclose the back of the pedestal, and a 2" knockout in the base of the stove for an outside air connection from under the floor. I assume the block-off plate would also have a knockout for a through-the-wall outside air connection.

Either way, the fan supplies the air for both combustion and convection with no way to separate the two.

That doesn't sound right. You shouldn't be using outside air to heat your house. Too inefficient. There must be a direct connect somewhere for outside combustion air.

my $02

 

[Lobstah]

sounds like they were trying to save $$$ by going with 1 fan.

Jim

 

[wilbilt]

That doesn't sound right. You shouldn't be using outside air to heat your house. Too inefficient. There must be a direct connect somewhere for outside combustion air.

my $02

I also think it would be inefficient, which is why I haven't connected it.

There is no direct connection to provide air to only the combustion fan, since the same fan supplies air for both.

The fan is an axial fan, similar to a computer fan, but is about 6" in diameter. It is bolted to the floor of the stove and pressurizes the entire inside of the "cube" that is the stove body under the hopper. At the front of the stove at the bottom, there are holes in a baffle that lead to the area under the burn pot for combustion air.

At the top of the stove the heat exchanger tubes are open to the interior and pass through the top of the firebox and then out to the room. There is no ducting inside the stove whatsoever. It is just a pressurized box. Some of the air supports combustion and goes out the exhaust, and the rest goes out through the heat exchanger into the room.

I am ready to try hooking up outside air, to see if it helps the draft effect (i.e., push heat toward the leaks instead of drawing in cold). If it adversely affects the heat output from the stove, I will remove it and continue running it the way it is now.

 

[wilbilt]

sounds like they were trying to save $$$ by going with 1 fan.

Jim

I don't know what they were thinking. It is an old stove, and almost certainly a 1980s design. The manufacturer has been out of business for over 10 years, so it is difficult to find any information.

Practically impossible, in fact. I have been trying to locate a manual or other info with zero success.

 

[Scoop]

An outside air connection is mandatory for pellet stoves installed in a mobile home so I think I'd hook one up. Your not heating that large an area so heating cold air shnouldn't make that much difference.

 

[cac4]

Just never thought that the stove would be able to draw that much air through the exhaust fans.

my forced hot air furnace is in the basement, and uses indoor air for combustion. The wife often leaves the basement door open, so that she can hear the clothes dryer "buzz" when its finished a load. When the furnace kicks on, that door will close all by itself, with "authority". The knob latches with a firm "ca-THUNK".

You shoud vent the furnace room. Not good that the furnace is creating that much of a negative pressure to close the door. Likely means your furnace is gasping for air with the door closed. Just install a return air wall plate somewhere in the furnace room wall close to the floor so it sucks cold air into the room.

my $.02

well, there is no "room"; its just "the basement". 24'x36' rectangle.
there are cold air return ducts throughout the house...but that wouldn't have any effect on combustion air. Maybe I should have an OAK for the burner...or maybe its the fact that its vented with a power-vent, rather than natural draft. either way, it consumes a lot of air, and it has to get it from somewhere.

Interesting thing I noticed: with the pellet stove running, I get a big draft coming UP from the basement. Don't quite understand why. The stove having an OAK in place would rule out "combustion"; maybe its just the hot air rising?

 

[Scoop]

In Canada you would instal a Venmar heat exchanger, which bring outside air in for combustion but mixes it with the inside air, so it doesn't cost you money to heat the outside air. U likely have something similar down there. These units usually arfe required by code in new home constructin in colder climates. Somehow you have to get more air into your basement so there isn't negative presure caused by combustion, IMHO.

Stan

 

[SmokeyTheBear]

Just never thought that the stove would be able to draw that much air through the exhaust fans.

my forced hot air furnace is in the basement, and uses indoor air for combustion. The wife often leaves the basement door open, so that she can hear the clothes dryer "buzz" when its finished a load. When the furnace kicks on, that door will close all by itself, with "authority". The knob latches with a firm "ca-THUNK".

You shoud vent the furnace room. Not good that the furnace is creating that much of a negative pressure to close the door. Likely means your furnace is gasping for air with the door closed. Just install a return air wall plate somewhere in the furnace room wall close to the floor so it sucks cold air into the room.

my $.02

well, there is no "room"; its just "the basement". 24'x36' rectangle.
there are cold air return ducts throughout the house...but that wouldn't have any effect on combustion air. Maybe I should have an OAK for the burner...or maybe its the fact that its vented with a power-vent, rather than natural draft. either way, it consumes a lot of air, and it has to get it from somewhere.

Interesting thing I noticed: with the pellet stove running, I get a big draft coming UP from the basement. Don't quite understand why. The stove having an OAK in place would rule out "combustion"; maybe its just the hot air rising?

A 250 CFM combustion fan can remove all of the air in your 24' x 36' house foot print every 55.296 minutes provided the house has 2 floor equivalents each with 8 foot ceilings.

 

[MCPO]

[quote author="

A 250 CFM combustion fan can remove all of the air in your 24' x 36' house foot print every 55.296 minutes provided the house has 2 floor equivalents each with 8 foot ceilings.

A 250 CFM combustion fan is 2.5 larger than my bathroom ceiling fan. Any pellet stove using one that large should be brought to the junk yard immediately.
I assume we are talking about a furnace fan?

 

[SmokeyTheBear]

Nope not the furnace a pellet stove, they all have combustion fans and they can and do suck really well.

A furnace also can do a number if it is not set up correctly. With the furnace you are not apt to really notice it since the doors to the living space are normally closed and the furnace area draws air from other sources such as the great outdoors (even without an OAK). If you do a bit of research you discover that combustion based central heating systems can waste a lot of energy if they aren't setup properly and I'm not talking burn efficiency.