I don't understand the OAK on my enviro empress

[2006empress]

I recently bought and installed a 10 year old Enviro Empress in my somewhat drafty 150 year old cape cod with original single pane windows and decent insulation. I'm using a small fan at floor level to attempt to move the heat through the very non-open floor plan downstairs. It's keeping the living room and bedrooms nice and warm, and the rest of the downstairs acceptably warm. I'm pretty darn happy so far.

I didn't install an OAK when I put in the stove. I'm thinking about putting one in, but I'm a little confused. When I look at the installation manual, it would appear that the OAK on this particular stove doesn't connect to the actual stove. It seems like the OAK is a 2" pipe that begins outside and terminates at the sheet metal at the back of the stove. But the housing into which the OAK terminates is itself open to the room through a series of vents. When I don't have the stove on, isn't the OAK on this stove just allowing air into my house?

If you look at page 8 of the manual (linked below), you see the back of the stove. The exhaust pipe on the right actually connects to the body of the stove. The fresh air pipe on the left, however, terminates with the body of the housing. There's no pipe connecting it to the combustion chamber. There's a void where air from the room and from the OAK mingle and are both sucked into the combustion chamber.

It doesn't seem like other stoves do this, correct? Am I misunderstanding?

Here's the link to the technical manual: http://www.enviro.com/images/manuals-brochures/tech-manuals/Empress-FS-Manual.pdf

 

[bcarton]

My old Enviro EF2 is built the same way. From what I've read, it's common with Enviro stoves. I don't have an OAK.

 

[2006empress]

Is there a workaround? I'd rather not have a 2" diameter hole in my wall, open 24/7/365 when I'm only running the stove 5 months/year.

is there a way to run a flexible tube in that steel housing on the back of the stove to connect the OAK directly to the combustion chamber?

 

[johneh]

Have you had the back panels off ?
I believe that with the unit open you will
see that the tube leads to the combustion area
behind the burn pot . That is the main area for
combustion air to enter

 

[2006empress]

See the attached photos. One shows the fresh air vent pipe leading into the housing on the back, with plenty of ventilation around it to allow in air from the room. The other picture is with one of the side panels of the housing removed. On the right you see where the OAK would attach to the back of the stove. On the left you see where the fresh air inlet would terminate. It's not actually connected directly to the combustion area behind the burn pot. It just sort of points near it.

I'm very happy with my current setup, but with 150 year old windows and doors (and handworked iron door latches that allow in a little air) I feel like I'd have less of a draft in the house in general if I installed a fresh air intake. That's why I'm trying so hard to get to the bottom of this.

I thought of putting some sort of a damper on the OAK where it goes outside (like on a bathroom vent, but in reverse). If I did that, however, the stove would still just pull in combustion air from the room, as there would be no suction to open the damper on the OAK.

 

[FirepotPete]

See the attached photos. One shows the fresh air vent pipe leading into the housing on the back, with plenty of ventilation around it to allow in air from the room. The other picture is with one of the side panels of the housing removed. On the right you see where the OAK would attach to the back of the stove. On the left you see where the fresh air inlet would terminate. It's not actually connected directly to the combustion area behind the burn pot. It just sort of points near it.

I'm very happy with my current setup, but with 150 year old windows and doors (and handworked iron door latches that allow in a little air) I feel like I'd have less of a draft in the house in general if I installed a fresh air intake. That's why I'm trying so hard to get to the bottom of this.

I thought of putting some sort of a damper on the OAK where it goes outside (like on a bathroom vent, but in reverse). If I did that, however, the stove would still just pull in combustion air from the room, as there would be no suction to open the damper on the OAK.

Looks like someone disconnected the interior pipe for the OAK. It's 10 years old, but did you have it all this time or did you buy it from someone?
Without knowing that stove itself can you see to the back of the burn chamber from the back of the stove and see if there is something blocking the burn chamber where the OAK pipe should have been?

 

[alternativeheat]

Some stoves are built that way, kind of a known issue. As to the OAK being open all year, most people block them off in the off season so critters don't get in anyway. I'd be more concerned about if the stove shuts down and having that open hole in the cold weather. I don't see why you couldn't fashion a baffle to close it off maybe attached to a rod ( for lack of a better term, create a choke plate).

Question for you though, where does the stove suck room air in from ? I hope nopt close to the combustion air or you might find yourself heating outdoor air over the heat exchanger.

 

[Threerun]

Is there a workaround? I'd rather not have a 2" diameter hole in my wall, open 24/7/365 when I'm only running the stove 5 months/year.

is there a way to run a flexible tube in that steel housing on the back of the stove to connect the OAK directly to the combustion chamber?

Is there a reason you need the OAK? I didn't install an OAK on my M55 and it's fine. We have a 20 year old 2,800 sq. ft house- we really don't need outside combustion air. If your house is 150 years old, I'd imagine the air in your house is fluid enough to operate the stove without an OAK (even with good insulation).

The only reason I would install an OAK would be if;
a) The unit itself absolutely requires it or;
b) I had a concern with negative pressure blowing out gas pilot light appliances in the home

Also there is another thread where someone showed a chimney design that incorporates a surrounding fresh air baffle for an OAK. No second hole in the wall required, and I doubt any critter can get into it. After the season is over simply cap the flue.

 

[FirepotPete]

we really don't need outside combustion air.

You're getting it anyways, the differential pressure of the stove using air for combustion and then going out the exhaust drags air from somewhere and that somewhere is from outside the house, simple physics.

 

[Threerun]

Yeah I know. That's why we didn't feel the need to punch another hole in the wall for an OAK. If our house was super tight it might be a different story.

 

[alternativeheat]

Yeah I know. That's why we didn't feel the need to punch another hole in the wall for an OAK. If our house was super tight it might be a different story.

I do. But may be a bit less so for that stove because of that intake design it has, it may well draw some room air anyway even with the hole in the wall.. The anti OAK crowd will never get why anyway though, they just figure the stove runs fine so everything is wonderful. Doesn't matter you're changing out the house air every hour or so to them because the combustion system draws that much air..

About OAK in general . Look at a conservative figure of 300 cubic feet every single minute is going up the vent pipe after combustion. Every single minute the stove is running it's taking 300 Cubic Feet of air and putting it up the vent pipe. It makes perfect sense to you that it should be heated air from inside your house going out the vent ? Not to me, not when it could be outside air going through combustion and back outside again, leaving my warm air to get recirculated through the heat exchanger. Add the loose house theory, everyone says the loose house is drafty anyway. Oh so good, lets draw from all the holes in the walls and suck in deliberately more outside cold air that needs heating from our expensive pellet fuel ! How does this possibly make any sense to anyone who is alive and breathing and even marginally thinking?

 

[Threerun]

I do. But may be a bit less so for that stove because of that intake design it has, it may well draw some room air anyway even with the hole in the wall.. The anti OAK crowd will never get why anyway though, they just figure the stove runs fine so everything is wonderful. Doesn't matter you're changing out the house air every hour or so to them because the combustion system draws that much air..

About OAK in general . Look at a conservative figure of 300 cubic feet every single minute is going up the vent pipe after combustion. Every single minute the stove is running it's taking 300 Cubic Feet of air and putting it up the vent pipe. It makes perfect sense to you that it should be heated air from inside your house going out the vent ? Not to me, not when it could be outside air going through combustion and back outside again, leaving my warm air to get recirculated through the heat exchanger. Add the loose house theory, everyone says the loose house is drafty anyway. Oh so good, lets draw from all the holes in the walls and suck in deliberately more outside cold air that needs heating from our expensive pellet fuel ! How does this possibly make any sense to anyone who is alive and breathing and even marginally thinking?

I'm not anti OAK nor am I a naysayer. I would be concerned if my house wasn't getting heated or if my pellet consumption was extraordinarily high- neither of those is the case. I'm heating my home on 1-1.5 bags p/day and I can exchange my air with fresh at the same time. I kinda like that, actually.

I have heated with wood or pellets for over 20 years never using OAK and have never had any issues what so ever. None. Why would I add additional expense to fix a problem that does not exist?

My dealer said run it without an OAK first, if not satisfied they'd put a hole through my concrete wall for me. That was their advice.

 

[Deezl Smoke]

I'm not anti OAK nor am I a naysayer. I would be concerned if my house wasn't getting heated or if my pellet consumption was extraordinarily high- neither of those is the case. I'm heating my home on 1-1.5 bags p/day and I can exchange my air with fresh at the same time. I kinda like that, actually.

I have heated with wood or pellets for over 20 years never using OAK and have never had any issues what so ever. None. Why would I add additional expense to fix a problem that does not exist?

My dealer said run it without an OAK first, if not satisfied they'd put a hole through my concrete wall for me. That was their advice.

You'll find that no matter what you say, if you do not have a kit hooked to your stove, you will get a constant barrage of negativity about your decision.

I do not have a kit on either of my stoves either.

 

[Pelleting In NJ]

A lot of stoves have a half-a** OAK design, where the pipe just opens into the unsealed interior of the stove.....lazy engineering and/or cost cutting. A proper stove has a sealed intake combustion path, that only connects to the OAK connection pipe on the back of the stove.

 

[johneh]

A proper stove has a sealed intake combustion path,

You are right no self respecting stove company
would sell a stove with out one ------------NOT------------

 

[stovelark]

Enough negativity please- The empress can have a direct connection- get a 1.5 inch metal pipe and hook into the air intake inside the stove housing, fill around with silicone to make airtight, then connect to a 2 inch intake scrunched down with a clamp to make it a positive fitting to the outside air source. Its done all the time with many stoves, not just enviro, some enviros (like the m55) have an intake plume, some don't. I have stoves with no OAKs, but many times they can help.

 

[Threerun]

Just for the record- I don't spend a lot of time on this forum but I just finished reading another recent thread and it certainly appears there is a whole OAK/No OAK flame debate going on. I DID NOT KNOW THAT, lol!

I see the OP wants to reduce drafts, so I totally get why they would want to try an OAK.. I would certainly follow stovelarks advice and try to make that a positive connection to the combustion chamber.

 

[2006empress]

I know I'm sucking in air from every corner of my only moderately insulated old house. I'm wondering if using an OAK would cut down on the drafts in some corners of the house. It's not causing any problems without an OAK, but if I'm sending 300 cf of heated air out of my house every minute...

 

[Threerun]

I know I'm sucking in air from every corner of my only moderately insulated old house. I'm wondering if using an OAK would cut down on the drafts in some corners of the house. It's not causing any problems without an OAK, but if I'm sending 300 cf of heated air out of my house every minute...

Comfort is the key for me. If I wasn't getting what I wanted with my current set-up I would certainly try installing an OAK.

I also must admit that my wife and I have always left a window cracked for fresh air, even in the dead of winter. A habit each of our families always had- let the house breathe. Our bedroom window is always cracked, and tonight it's supposed to be -10!

 

[Wilbur Feral]

To the original question, some stoves sadly are designed poorly for their OAK connection. Others have spoken to how to address it, so no need to address again.

To those that don't understand the need for properly managing air exchange in your home, we cannot help you. I once thought we could, but time has proven me wrong. Some things you just can't fix...

 

[Deezl Smoke]

To the original question, some stoves sadly are designed poorly for their OAK connection. Others have spoken to how to address it, so no need to address again.

To those that don't understand the need for properly managing air exchange in your home, we cannot help you. I once thought we could, but time has proven me wrong. Some things you just can't fix...

Some people smoke tobacco. Some drink alcohol in excess. Others will spend many thousands on tattoos and other personal mutations. Are you gong to judge them too?

If someone comes here asking about how to fix an issue and advice is given and taken, the problem is fixed and all is good. But no one has a right to judge others that do not ask for advice, but simply state that they like their setup even though it does not meet critical acceptance.

I watch people every trip to the grocery store, stand at the frozen goods isle complaining to their friends about the price of food all the while standing with the freezer door wide open, just thinking about what to buy when the glass door was perfectly clear.

 

[Pelleting In NJ]

Tatoos, food, alcohol use, colors.....these are individual choices.....OAK is simple science.....like "Is the Earth flat or round?".......

 

[alternativeheat]

Some people smoke tobacco. Some drink alcohol in excess. Others will spend many thousands on tattoos and other personal mutations. Are you gong to judge them too?

If someone comes here asking about how to fix an issue and advice is given and taken, the problem is fixed and all is good. But no one has a right to judge others that do not ask for advice, but simply state that they like their setup even though it does not meet critical acceptance.

I watch people every trip to the grocery store, stand at the frozen goods isle complaining to their friends about the price of food all the while standing with the freezer door wide open, just thinking about what to buy when the glass door was perfectly clear.

I won't get into Your judgment calls on the above situations, but.

On the OAK: there is a simple fact at work here, it's a physical action. With a proper OAK set up the stove burns with outdoor air not indoor already heated air. It's totally your business if you choose to use indoor payed for heated air and send it out your flue pipe only to be replaced with outdoor cold air. Don't ask us to make any sense of that, but you have the right to do it for sure.

 

[alternativeheat]

Yeah I know. That's why we didn't feel the need to punch another hole in the wall for an OAK. If our house was super tight it might be a different story.

Threerun, if you like having a window open in your house and if it were my call which it is not, then I don't think I'd pay for the expense of an OAK either. In that case there isn't much purpose to having an OAK.

 

[FirepotPete]

Here's a different way to look at the OAK issue. An analogy using a refrigerator.

Your refrigerator is a closed system, it uses air from the house to pass over heat exchanging fins from the compressor. The interior of the refrigerator in closed, sealed from outside air, the only air that moves in the frig is the air inside it.

A frig should keep the air between 33*F and 42*F. Lets say you like your food at 35*F, so you run the frig for a while and get the settings where you like them, say 35*F. Now one of the seals on the door goes bad, but you don't really know that. The frig slowly goes up to 37*F, do you notice? Probably not. But what will happen is that the frig will run more trying to get the temp back to 35*F, you may not even notice that. Being the frig is running more it is also running harder, shortening the life of the compressor and raising you electric costs.

So you may feel nice and cozy, your fuel use is fine with you, but you are burning more fuel than you need and would, without a doubt get better results, cheaper and more efficiently with an OAK.