# Enviro Mini - Sorry - But Yet Another OAK (Outside Air Kit) Question



## LI-Mini-Owner (Feb 14, 2010)

I don't have an OAK connected to my Enviro Mini, and really don't have any problem with getting enough combustion air, though I do get a little concerned at times like when I run the kitchen range hood, or bathroom fan.   Guess my house is leaky enough  .   Now the main reason I never hooked it up was because of how my stove is configured for OAK.  From reading other threads I get the impression that some stoves duct the OAK right to the intake for the burn pot, so there is no chance for any room air to be used for combustion.  Is this true for any of your stoves?

My stove simply terminates the OAK inside the cabinet of the stove.  IMO room air could blend with outside air for combustion, and when stove is off I would think that cold outside air could blow into the room via the slots in the rear of the stove cabinet.  For these reasons I'm wondering if I'd be worse off with OAK.

Here are some snapshots to illustrate my stove...

Thanks in advance for any comments.

Carl


----------



## SmokeyTheBear (Feb 14, 2010)

The OAK should connect to that pipe in the second picture.


----------



## Dr_Drum (Feb 14, 2010)

Are you sure there isn't a part missing? My Lopi appears to have an air gap around the cast iron intake plenum (manifold thing). I think it pulls room air in whether using an OAK or not. I don't notice any difference with or without it, but your situation there is far more drastic with the open-ended pipe stub. When you consider all the open space to the room, I wouldn't think it would draw much from an OAK anyway?
Mike -


----------



## Dr_Drum (Feb 14, 2010)

SmokeyTheBear said:
			
		

> The OAK should connect to that pipe in the second picture.



Smokey, I think he's showing us both sides of the same pipe. Pic#1 connection point on outside of stove, Pic#2 is same pipe inside cabinet of stove? Maybe he can verify that for us?
Mike -


----------



## SmokeyTheBear (Feb 14, 2010)

I was wondering about that Mike, I just wanted him to say something like it's the same piece of pipe.

There is no question on mine that connecting the OAK prevents any room air entering the air intake.

All Carl need to do is follow the actual air path.


----------



## imacman (Feb 15, 2010)

IMO, unless there's a piece of tubing missing that's supposed to go between the tube in pic # 2 and the hole under the ignitor in pic #3, hooking up an OAK to the stove is close to being worthless.


----------



## ChandlerR (Feb 15, 2010)

Not only that, but if an OAK was connected to that pipe, there would essentially be a 4 inch draft of cold air coming into the house. In my uneducated guess, I would say something is missing.  I wouldn't be connecting an OAK to that pipe.

Chan


----------



## imacman (Feb 15, 2010)

CWR said:
			
		

> Not only that, but if an OAK was connected to that pipe, there would essentially be a 4 inch draft of cold air coming into the house.......



Yep, that too......good catch Chan.


----------



## SmokeyTheBear (Feb 15, 2010)

Well looky who showed up, well folks since the OP hasn't been back yet you are all speculating on what may or may not be missing.


----------



## terryjd98 (Feb 15, 2010)

On my Enviro Evolution my OAK that I never hooked up yet is just a short pipe inside the stove. Have to go about guessing 4 inches to get to oustide the cabinet housing which there is a 2 inch hole in it for pipe to go through. The back of the cabinet, (guess thats what you would call the metal surrounding the back of the stove)  has a bunch of slots in it so that short pipe can suck air through them anyways.
 Maybe I am missing a piece or its an Enviro thing. I can take some pics tomorrow of how my OAK pipe looks on the stove if wanted.


----------



## LI-Mini-Owner (Feb 15, 2010)

SmokeyTheBear said:
			
		

> I was wondering about that Mike, I just wanted him to say something like it's the same piece of pipe.
> 
> There is no question on mine that connecting the OAK prevents any room air entering the air intake.
> 
> All Carl need to do is follow the actual air path.



Correct - The first picture is what sticks out the stove, the second picture is the other end of that pipe that sticks a few inches into the cabinet.   The 3rd picture shows where all the combustion air will get sucked into, and it's like 8" away from the end of the pipe shown in the 2nd picture.  

To Macman's point I wondered if there were parts missing, like something that goes over the combustion intake hole and around the igniter inlet that transitions to flex pipe that would connect to the end of the tube shown in the second picture.


----------



## Dougsey (Feb 15, 2010)

This stove is a great example of why an OAK is not always a good idea.


----------



## SmokeyTheBear (Feb 15, 2010)

Carl,

I've heard others on here talk about their stoves having an OAK and also slots that allowed room air in, they never did put up any pictures.  So I don't know if the OAK would cover the slots when installed or if the slots would still be operable.

My stove has the air intake ending at the back of the firebox under the burn pot.  Both burn pot air ports and the igniter assembly are inside the intake.

There is also one stove (the name escapes me now) that requires you to get an adapter in order to use the outside air feature.

I'd say call the manufacturer and ask.


----------



## j00fek (Feb 15, 2010)

i put in the OAK this yr, ill never go back, just unhook it in the summer


----------



## hoverfly (Feb 15, 2010)

It's the same way on my Mini, I seem to have no problem with the set up, however some type of piping to combustion air intakes would be nice.


----------



## Dr_Drum (Feb 15, 2010)

The owners manual (here: www.enviro.com/.../manuals...manuals/C-11624 Instruction Mini A Technical Manual.pdf)
does say that hole next to the ignitor is the air intake. Reference to an "Air Intake Tube" is also shown on page 10. The technical manual (here: www.enviro.com/.../manuals...manuals/C-11624 Instruction Mini A Technical Manual.pdf) however does not show a specific part for this "air intake tube". Probably easiest to call.
Mike -


----------



## breklaw (Feb 15, 2010)

I agree that with the current setup I would not hook it up. OAK is supposed to make it so you only burn outside, UNHEATED air, thereby lowering the amount of negative pressure in the house, which means less cold air coming in through cracks and such. If you are burning inside air, you are burning air you have paid to heat already! This is why fireplaces are so inefficient.  Plus, now to replace that already paid for heated air, you have outside air coming in to replace it. Nature ABHORS a vacuum.
Bill


----------



## Jabberwocky (Jun 27, 2010)

Any QuadraFire owners out there with an OAK.  My dealer seemed sorta cynical about it mentioning something about pests getting access but I have a HUGE problem with cold air getting sucked up from the basement.  When that stove runs that floor gets cold! Part of that is obviosuly due a furnace no longer heating a basement but I can feel the air whirring up from downstairs.  Efforts to ask the wife to close the basement door have failed so I have to family-proof this thing.


----------



## imacman (Jun 27, 2010)

Jabberwocky said:
			
		

> Any QuadraFire owners out there with an OAK.  My dealer seemed sorta cynical about it mentioning something about pests getting access but I have a HUGE problem with cold air getting sucked up from the basement.  When that stove runs that floor gets cold! Part of that is obviosuly due a furnace no longer heating a basement but I can feel the air whirring up from downstairs.  Efforts to ask the wife to close the basement door have failed so I have to family-proof this thing.



I'm not an Quad owner, but adding an OAK cannot make things worse....it can only help, IMO.


----------



## SmokeyTheBear (Jun 27, 2010)

As for the issue with the never closed basement door, get a big honking padlock install it and keep one key with you and the other at work.

As for pests tell your "dealer" he just became one, you block it off in the off season.

Then the only question I'd have since I'm not a quad owner is are there any special parts that need to purchased such as an adapter that seals the air path (there are some strange configurations out there).


----------



## stovelark (Jun 28, 2010)

OK Smart Enviro owner (Proud owner of 3 enviro stoves.  On the mini and most enviros, the fresh air tube inlet is just a guide spot.  Take a 1 inch or 1.5 inch metal tube and connect it from the stoveback tube and connect it mechanically (via screws and L bracket to the inner stove shell.  Put hi temp silicone in air tube inside to block out all internal house airflow into the stove.  Then hook up flex tubing through the wall to outside of house.  Remember to seal all external connections with silicone and appropriate screens to keep critters out.  Outside air will almost always make a stove run better, cold dense combustion air is great if you seal the intake path to the stove only and do not put another hole in your house to let cold air in.  As an installer, I see it a lot.  Don't forget to properly adjust the air damper too.  In case anyone is wondering, lots of manufacturers leave outside air inputs open, Breckwell inserts are known for it, kinda hard to hook up to stove body too.  They make nice stoves too.  Hope this helps.

     Stovelark
     Enviro 1700 FS wood
     Enviro EF3 FS
     Enviro Empress Insert  (can you tell I like ENVIRO?)


----------



## Jabberwocky (Jun 28, 2010)

SmokeyTheBear said:
			
		

> As for the issue with the never closed basement door, get a big honking padlock install it and keep one key with you and the other at work.
> 
> .



Still working on teaching about closing the doors before leaving the house, actual locking of said doors may be a pipe dream at this point.


----------



## smwilliamson (Jun 29, 2010)

Many say that installing an OAK really has more to do with overall efficiency of the heater. I have to disagree. Heating a small home with such an appliance as a pellet heater can be harmful to the health of the occupants if the air is not handled properly.

The mini is not alone in the line up of Enviro pellet stoves that are NOT readily equipped to handle an OAK properly. In fact, many manufacturers neglect to tie in the heater cartridge (igniter) with the combustion air port. For a heater to be maximumly efficient and truly separated from the inside air,  ALL combustion air which enters the appliance should be completely separated from the convection air or room air. 

Last winter I ordered a new Magnehelic Gauge to read 0-0.25 inches of water column. I was setting it up in my kitchen and was immediately thinking it was broken, as it measured .09 while just sitting the table. I shut down the pellet stove across the living room and was astounded that the gauge went back to zero. Immediately.

This prompted me to install an OAK. Let me tell you, it was not easy to completely seal the stove up, even with the recommended pipes.

I did talk with my pediatrician though about the effects of my kids living in a house that was under constant negative pressure. She called it a "sick house" or a house that does not produce make up air.

This is caused by too much air leaving the house through various sources (a pellet stove) and the inability of replacement air to have an easy access into the house replacing the air and oxygen used when the living conditions such as heat is rising, exhaust fans are operating, or combustion appliances and people are using up the air and oxygen.

This is why all mobile homes require an OAK. I would lump in any home under 1500 sqft too, which mine is.


----------



## Enviro Mini Owner (Feb 18, 2013)

LI-Mini-Owner said:


> I don't have an OAK connected to my Enviro Mini, and really don't have any problem with getting enough combustion air, though I do get a little concerned at times like when I run the kitchen range hood, or bathroom fan. Guess my house is leaky enough . Now the main reason I never hooked it up was because of how my stove is configured for OAK. From reading other threads I get the impression that some stoves duct the OAK right to the intake for the burn pot, so there is no chance for any room air to be used for combustion. Is this true for any of your stoves?
> 
> My stove simply terminates the OAK inside the cabinet of the stove. IMO room air could blend with outside air for combustion, and when stove is off I would think that cold outside air could blow into the room via the slots in the rear of the stove cabinet. For these reasons I'm wondering if I'd be worse off with OAK.
> 
> ...


As another Long Island Mini owner thinking about adding an OAK, I would be interested to know what you finally did about outside air.


----------



## Pelleting In NJ (Feb 18, 2013)

It is amazing that so many stoves have a "fake" Outside Air system.....the manufacturer should be embarrassed !


----------



## DexterDay (Feb 18, 2013)

Jabberwocky said:


> Any QuadraFire owners out there with an OAK.  My dealer seemed sorta cynical about it mentioning something about pests getting access but I have a HUGE problem with cold air getting sucked up from the basement.  When that stove runs that floor gets cold! Part of that is obviosuly due a furnace no longer heating a basement but I can feel the air whirring up from downstairs.  Efforts to ask the wife to close the basement door have failed so I have to family-proof this thing.



I have an OAK on mine. I did a pretty good job sealing all holes, and cracks in my system. 

Even if you don't, the air will take the path of least resistance. It would rather come in that 3" vent that's a few inches away from the intake source, than come in through your bedroom window 35' away. IMO.

OAK's always help....


----------



## Don2222 (Feb 18, 2013)

smwilliamson said:


> Many say that installing an OAK really has more to do with overall efficiency of the heater. I have to disagree. Heating a small home with such an appliance as a pellet heater can be harmful to the health of the occupants if the air is not handled properly.
> 
> The mini is not alone in the line up of Enviro pellet stoves that are NOT readily equipped to handle an OAK properly. In fact, many manufacturers neglect to tie in the heater cartridge (igniter) with the combustion air port. For a heater to be maximumly efficient and truly separated from the inside air, ALL combustion air which enters the appliance should be completely separated from the convection air or room air.
> 
> ...


 
Most OAKs take cold and sometimes damp air from the outside which unfortunately reduce the overall efficiency of the pellet heater. It's like putting damp and cold wood into a wood stove!

The absolute best solution is to pre-heat that outside air to make it warm and keep it dry with Selkirk DT venting that I install.

see pic below


----------



## LI-Mini-Owner (Feb 19, 2013)

Enviro Mini Owner said:


> As another Long Island Mini owner thinking about adding an OAK, I would be interested to know what you finally did about outside air.


 
I replaced my vent/thimble this year because I had the house re-sided.  I installed a Simpson Duravent thimble with a build in OAK.  Even though it doesn't terminate at the burn pot, at least I know the stove isn't competing for air.


----------



## Enviro Mini Owner (Feb 19, 2013)

I went ahead and had an OAK installed. Even though it is not a perfect connection as detailed above, it has allowed me to leave the forced air vents from the gas furnace open that were the stoves source for air, dragging the cold basement air up into the house. Everyone of them, we live in a small cottage, was a torrent of air.


----------



## DBCOOPER (Feb 19, 2013)

Don2222 said:


> Most OAKs take cold and sometimes damp air from the outside which unfortunately reduce the overall efficiency of the pellet heater. It's like putting damp and cold wood into a wood stove!
> 
> The absolute best solution is to pre-heat that outside air to make it warm and keep it dry with Selkirk DT venting that I install.
> 
> see pic below


 

Are you saying that preheating the air drys it?  Where does the moisture go?


----------



## jhanan (Mar 8, 2014)

stovelark said:


> OK Smart Enviro owner (Proud owner of 3 enviro stoves.  On the mini and most enviros, the fresh air tube inlet is just a guide spot.  Take a 1 inch or 1.5 inch metal tube and connect it from the stoveback tube and connect it mechanically (via screws and L bracket to the inner stove shell.  Put hi temp silicone in air tube inside to block out all internal house airflow into the stove.  Then hook up flex tubing through the wall to outside of house.  Remember to seal all external connections with silicone and appropriate screens to keep critters out.  Outside air will almost always make a stove run better, cold dense combustion air is great if you seal the intake path to the stove only and do not put another hole in your house to let cold air in.  As an installer, I see it a lot.  Don't forget to properly adjust the air damper too.  In case anyone is wondering, lots of manufacturers leave outside air inputs open, Breckwell inserts are known for it, kinda hard to hook up to stove body too.  They make nice stoves too.  Hope this helps.
> 
> Stovelark
> Enviro 1700 FS wood
> ...



Thanks, this answer some of my questions about the OAK connection on the Mini I'm installing right now.  I also though it was missing parts to the burn box.  Now, what about the large air intake hole between the draft slider and the combustion fan.  That is strange design to me as well.  I guess the design mixes house air with exhaust air on right before the combustion fan.  I guess the design is like the air max flapper on my furnace exhaust ducting.


----------



## jhanan (Mar 8, 2014)

Also it looks like my stove arrived with the "with the little flapping door" missing  Will have call dealer on Monday.  Is the door optional.  Thinking about making a temporary solution.  The door is to the fan box where that vacuum sensor hose terminates.


----------



## jhanan (Mar 9, 2014)

My stove is missing the backdraft flapper part  50-1542.  Dang it.  I will make one till I can get the OEM part.

http://www.stove-parts-unlimited.com/Enviro-Pellet-Backdraft-Flap-with-Gasket-p/50-1542.htm


----------



## Mt Bob (Mar 9, 2014)

chickenman said:


> Here! Here!


 Before you jump on the"fake OAK" bandwagon,Realize a lot of european stoves were/are made this way,some american stoves have bleed holes(shudder everytime someone writes they taped/blocked them).Cold air reduces availible heat,hence the design of your stoves pipe system,same as a bixby.There also may be safety reasons for these designs,as something bad could happen with total air blockage.


----------



## hockeypuck (Mar 9, 2014)

stovelark said:


> OK Smart Enviro owner (Proud owner of 3 enviro stoves.  On the mini and most enviros, the fresh air tube inlet is just a guide spot.  Take a 1 inch or 1.5 inch metal tube and connect it from the stoveback tube and connect it mechanically (via screws and L bracket to the inner stove shell.  Put hi temp silicone in air tube inside to block out all internal house airflow into the stove.  Then hook up flex tubing through the wall to outside of house.  Remember to seal all external connections with silicone and appropriate screens to keep critters out.  Outside air will almost always make a stove run better, cold dense combustion air is great if you seal the intake path to the stove only and do not put another hole in your house to let cold air in.  As an installer, I see it a lot.  Don't forget to properly adjust the air damper too.  In case anyone is wondering, lots of manufacturers leave outside air inputs open, Breckwell inserts are known for it, kinda hard to hook up to stove body too.  They make nice stoves too.  Hope this helps.
> 
> Stovelark
> Enviro 1700 FS wood
> ...




I would be afraid of voiding any warranties by doing this.  The enviro, like many other stoves, do not direct the outside air into the air intake port.  Why they want to mix inside air is anyone's guess.  Could be safety reasons... ie the oak gets blocked or it also could be they want to blend the cold air with warmer air before combustion.   "Gerryrigging" your own thoughts on what an OAK should be could be dangerous.  This is one of the reasons why I do not feel the urge to install the OAK.  Until I figure a way to install some sort of automatic damper to open and close the air supply, I will not be using one.  My stove does not run 24/7, so why would I want cold air pouring into my room.  I have enough leaking window that already does this.. I do not need any more drafts.


----------



## Mt Bob (Mar 9, 2014)

hockeypuck said:


> I would be afraid of voiding any warranties by doing this.  The enviro, like many other stoves, do not direct the outside air into the air intake port.  Why they want to mix inside air is anyone's guess.  Could be safety reasons... ie the oak gets blocked or it also could be they want to blend the cold air with warmer air before combustion.   "Gerryrigging" your own thoughts on what an OAK should be could be dangerous.  This is one of the reasons why I do not feel the urge to install the OAK.  Until I figure a way to install some sort of automatic damper to open and close the air supply, I will not be using one.  My stove does not run 24/7, so why would I want cold air pouring into my room.  I have enough leaking window that already does this.. I do not need any more drafts.


 Good to see some common sense.Appears some people did not pay attention in school.One reason for a blended system is in case of house depressurization,smoke does not get drawn into house as bad.Do not have an oak as I shut stove off during day a lot,and run it on low a lot,however adding a water valve to a oak would be easy.European stove installers sell oak sets with a simple shutoff made in pipe,if you are interested.          http://www.woodheat.org/the-outdoor-air-myth-exposed.html


----------



## jhanan (Mar 9, 2014)

The design does not make sense.  My US Stove OAK is a direct connect to the outside so there is no cold air dumping into the room.


----------



## jhanan (Mar 9, 2014)

bob bare said:


> Good to see some common sense.Appears some people did not pay attention in school.One reason for a blended system is in case of house depressurization,smoke does not get drawn into house as bad.Do not have an oak as I shut stove off during day a lot,and run it on low a lot,however adding a water valve to a oak would be easy.European stove installers sell oak sets with a simple shutoff made in pipe,if you are interested.          http://www.woodheat.org/the-outdoor-air-myth-exposed.html



Pellet stove is a forced air system - so does this apply?  Anyway - a value would be must and you have to now remember to turn it on and off.


----------



## Mt Bob (Mar 9, 2014)

jhanan said:


> Pellet stove is a forced air system - so does this apply?  Anyway - a value would be must and you have to now remember to turn it on and off.


What part not apply?Also,most of the rest of the world does not waste heat the way we do,so walking over and shutting a valve is nothing to them.(heat costs lots more for them)


----------



## batchman (Mar 9, 2014)

jhanan said:


> My stove is missing the backdraft flapper part  50-1542.  Dang it.  I will make one till I can get the OEM part.



On my Maxx, I found I was getting very little draft through the OA pipe.  I removed the backdraft flapper and it improved enough to at least  hold a piece of paper over the open end of the pipe - but not even dimple it.  I'm starting to think about a vacuum controlled flapper valve in the OAK.

I think too much.

Cheers,
- Jeff


----------



## Mt Bob (Mar 9, 2014)

batchman said:


> On my Maxx, I found I was getting very little draft through the OA pipe.  I removed the backdraft flapper and it improved enough to at least  hold a piece of paper over the open end of the pipe - but not even dimple it.  I'm starting to think about a vacuum controlled flapper valve in the OAK.
> 
> I think too much.
> 
> ...


 Actually good idea.


----------



## Mt Bob (Mar 9, 2014)

chickenman said:


> There is only one reason why all stoves do not come with a sealed system, heat exchanging OAK.  Cost.
> Manufacturers can give you all kinds of crazy reasons but it all comes down to the fact that it is more expensive to design and build.  They are just saving money, the rest is nonsense.


 We can agree to disagree.But why do some stoves that oak is directed to firebox have holes drilled and a stopper flange so they cannot be covered?I think engineers know more than us.


----------



## Mt Bob (Mar 9, 2014)

Thanks for reply.I see you,me and don agree preheated air is better for combustion,especially in colder weather.As my unit is old,that would make sense,and I have heard enviros had wind problems,so that was their fix.You do know you are going to make some people mad with that "running in cold climate" statement! By the way,montana is generally way warmer than the upper mid west(michigan,etc) just cooler weather lasts longer out here.Lots of days stove only runs a few hours.


----------



## Mt Bob (Mar 9, 2014)

What I meant was there are a lot of oak people that think it makes all stoves run better,all weather,all oak configurations.But in the last 2 weeks it has been anywhere from -30 to 50,but I am in the mountains,6500',most people live in the valleys.


----------



## Mt Bob (Mar 9, 2014)

Do some research,i run an austroflamm,has a mass air flow sensor(bmw)was specifically designed to run at all altutides.Some of the Italian stoves use this system now,so suppose they would work.Have worked on other stoves at higher altitudes,usually have to bypass vacuum sensor(older ones) but if had pressure sensor was ok(some whitfields.etc)Best to have short exhaust when going higher in mountains.This is just my experiences,auto mechanic by trade.Best way to approach problem(altutide)is speed up combustion blower.Need more volume for same o2 content.


----------



## Mt Bob (Mar 9, 2014)

I agree.The older st croix multi fuel manual control stoves do well up high,do not know about corn.If you have rich customers,take a look at rikas pellet and wood combo stove.


----------



## jhanan (Mar 9, 2014)

batchman said:


> On my Maxx, I found I was getting very little draft through the OA pipe.  I removed the backdraft flapper and it improved enough to at least  hold a piece of paper over the open end of the pipe - but not even dimple it.  I'm starting to think about a vacuum controlled flapper valve in the OAK.
> 
> I think too much.
> 
> ...



Why remove the backdraft flapper?  If it removed, then the combustion fan will draw all the air through the backdraft hole instead of through the burn chamber.


----------



## batchman (Mar 10, 2014)

jhanan said:


> Why remove the backdraft flapper?  If it removed, then the combustion fan will draw all the air through the backdraft hole instead of through the burn chamber.



Well I don't know where that piece is on the subject stove, but on mine it is in the OAK inlet.  I found that running on pretty high setting I was not drawing enough air through the pipe I've attached to matter.  I pulled the pipe off and could see the flap moving ever so slightly - not much draft happening there.  So I made sure it wasn't bound up, then pulled it.  Now my OAK pipe can at least hold a piece of paper in place - before not even that.

Cheers,
- Jeff


----------



## jhanan (Mar 10, 2014)

batchman said:


> Well I don't know where that piece is on the subject stove, but on mine it is in the OAK inlet.  I found that running on pretty high setting I was not drawing enough air through the pipe I've attached to matter.  I pulled the pipe off and could see the flap moving ever so slightly - not much draft happening there.  So I made sure it wasn't bound up, then pulled it.  Now my OAK pipe can at least hold a piece of paper in place - before not even that.
> 
> Cheers,
> - Jeff



Ahhh, OK, so your OAK has a damper.  Ya, you got have that probably wide open for sure.


----------

