Harman now STRONGLY recommends Outside Air

[LIpelletpig]

OK...I had some time on my hands and was researching on adding a OAK to my Accentra Insert before the upcoming heating season. I went back to the Install and operating manual and read through it for the 100th time. I then checked the website for Harman and looked up the accentra insert and under VENTING the section was updated Actualy many updates were made in the manual, not just venting (HHT Limited Lifetime Warranty). Harman now STRONGLY recommends attaching outside air in all installations, especially lower level and main floor locations. It also goes on to say for all horizontal venting configurations and for all installations in basements locations outside air is REQUIRED. In the old manual it was only optional and not required except in mobile home installs. This information is all under the Venting section in the manual which also included Negative pressure, shut-down and power failure probabilities and how to prevent a back draft situation. I found it all to be really useful and interesting. I think many people will now start to think about installing an OAK. I was going to do it anyway this year as my late summer project. My only gripe about it is I'm going to have to go through the back of the chimney wall through the brick to the outside.

I really recommend anyone who owns a Harman Pellet Stove to read the Hearth & Home Technologies Inc. LIMITED LIFETIME WARRANTY....it's the last few pages of the specific manual for your stove. It outlines specifics on what is covered and not covered and the length of time of the coverage. When I purchased my stove a year ago I thought I had a HARMAN GOLD WARRANTY for 6 years. Not sure if I am grandfathered in to the new warranty but it does seem a little misleading.

Hope the info helps!

 

[imacman]

..... Harman now STRONGLY recommends attaching outside air in all installations, especially lower level and main floor locations. It also goes on to say for all horizontal venting configurations and for all installations in basements locations outside air is REQUIRED......

Hmmmm....interesting. I seem to remember quite a few pellet stove owners poo-pooing the idea that outside air was needed when I recommended people add it to any pellet stove.

Since Harman is the "be all-end all" in pellet stoves to so many, I hope this controversy is over. And so much for the pellet stove installers ("experts") who have told many homeowners that it "isn't needed and we never put them in".

 

[MCPO]

Just because a pellet stove appears to run fine without a OAK doesn`t necessarily mean it doesn`t need one.
The benefits might not always be obvious by looking at the flame.
Why go through all the the trouble and expense of installing a pellet stove and omit this rather simple , low cost part of it.

 

[tjnamtiw]

Just because a pellet stove appears to run fine without a OAK doesn`t necessarily mean it doesn`t need one.
The benefits might not always be obvious by looking at the flame.
Why go through all the the trouble and expense of installing a pellet stove and omit this rather simple , low cost part of it.

Not to be a poo poo'r, but adding an OAK is NOT a 'rather simple, low cost part of it'... For instance, the OP has to cut through brick, studs, and his outside wall to add one. In my case, one of my fireplaces is on an inside wall with no access at all to outside air except to run an extra 17 foot long flexible pipe up my chinmey and out along side of the exhaust pipe. No where in the Quad literature does it say how long this OAK line can be without restricting the ability of the combustion blower to acheive proper flow. I'd love to do it, but I just don't know how in my case.
My other stove insert has an ash dump plate in the floor of the fireplace so I could go out there. These stoves also take in room air through the hopper since it isn't sealed. I assume there is no seal so that airflow goes into the firebox rather than very hot air filtering back up into the pellets in the hopper.

 

[CrappieKeith]

I don't care what you have that burns a flame...that appliance expels air out of the home.
Add in hot water heaters ,clothes dryers,exhausts in the bathroom and you can make a vacuum in your home which is a negative pressure that hurts the operation of a bio mass heater.
Good to see other manufactures signing on to this principle.

 

[ducker]

I don't care what you have that burns a flame...that appliance expels air out of the home.
Add in hot water heaters ,clothes dryers,exhausts in the bathroom and you can make a vacuum in your home which is a negative pressure that hurts the operation of a bio mass heater.
Good to see other manufactures signing on to this principle.

Unless your house is 100 years old, then I really doubt you're going to find yourself in much of a vacuum at all.

 

[countk]

I don't care what you have that burns a flame...that appliance expels air out of the home.
Add in hot water heaters ,clothes dryers,exhausts in the bathroom and you can make a vacuum in your home which is a negative pressure that hurts the operation of a bio mass heater.
Good to see other manufactures signing on to this principle.

Unless your house is 100 years old, then I really doubt you're going to find yourself in much of a vacuum at all.

Or 200 years old like mine.

 

[smoke show]

:question: hh:

 

[MainePellethead]

I have in the past contemplated an OAK....would it cause you to burn more pellets?

 

[MCPO]

Just because a pellet stove appears to run fine without a OAK doesn`t necessarily mean it doesn`t need one.
The benefits might not always be obvious by looking at the flame.
Why go through all the the trouble and expense of installing a pellet stove and omit this rather simple , low cost part of it.

Not to be a poo poo'r, but adding an OAK is NOT a 'rather simple, low cost part of it'... For instance, the OP has to cut through brick, studs, and his outside wall to add one. In my case, one of my fireplaces is on an inside wall with no access at all to outside air except to run an extra 17 foot long flexible pipe up my chinmey and out along side of the exhaust pipe. No where in the Quad literature does it say how long this OAK line can be without restricting the ability of the combustion blower to acheive proper flow. I'd love to do it, but I just don't know how in my case.
My other stove insert has an ash dump plate in the floor of the fireplace so I could go out there. These stoves also take in room air through the hopper since it isn't sealed. I assume there is no seal so that airflow goes into the firebox rather than very hot air filtering back up into the pellets in the hopper.

OK, I understand there are some situations where an OAK becomes more difficult to install but it doesn`t change the need for one.

 

[MCPO]

I don't care what you have that burns a flame...that appliance expels air out of the home.
Add in hot water heaters ,clothes dryers,exhausts in the bathroom and you can make a vacuum in your home which is a negative pressure that hurts the operation of a bio mass heater.
Good to see other manufactures signing on to this principle.

Unless your house is 100 years old, then I really doubt you're going to find yourself in much of a vacuum at all.

Or 200 years old like mine.

In this day and age there should be few excuses for living in a drafty home, not even a 200 yr old one.
And why would anyone who does live in a drafty old house want to add more draft?

 

[MCPO]

I don't care what you have that burns a flame...that appliance expels air out of the home.
Add in hot water heaters ,clothes dryers,exhausts in the bathroom and you can make a vacuum in your home which is a negative pressure that hurts the operation of a bio mass heater.
Good to see other manufactures signing on to this principle.

Unless your house is 100 years old, then I really doubt you're going to find yourself in much of a vacuum at all.

Or 200 years old like mine.

In this day and age there should be few excuses for living in a drafty home, not even a 200 yr old one.
And why would anyone who does live in a drafty old house want to add more draft?

correct but inversely too tight a home needs more draft for occupants to breathe unpolluted indoor air....its a canundrum!

I understand your point but I still can`t accept it as an excuse not to install an OAK. The house would have needed more air even if the stove wasn`t installed. Intalling an OAK directly into the pellet stove should not change the existing condition.

 

[MCPO]

[quote author="n.

scenario 4u= house is fairly tight & pstove is main source of heat. centralized. non-oak creates vacumn at heatsource which will result in sucking in dry outdoor air thru exterior wall leaks & drying the inflow spots. with oak the heat would flow into those leaky spots & deposit humidity for possible mold environment[/quote]

Heh,heh,heh. So what you are saying is that the above faulty pre-existing condition / scenario can be addressed by eliminating the OAK. I guess it would help but do you honestly believe it to be a proper solution?
Wouldn`t it make more sense to repair / eliminate any faulty condition with a more suitable method than relying on intake air drafts caused by a pellet stove ?
Pook, I think you are pulling my chain.

 

[smoke show]

hypothetically speaking of course

 

[mnkywrnch]

gotta love pook=good time

 

[stoveguy2esw]

about time they did, we have required it for several years.

anyway , one more time i'll go through this;pellet stoves,(and woodstoves though they dont use as much) like may other appliances such as(oil or gas or coal) central furnaces and even woodstoves, all need air to burn the fuel they use. this air once it passes through the fire leaves the stucture. this air has to come from somewhere and the void left by its departure must be filled or a vacuum will result.basic physics.

an appliance like a pellet or biomass stove utilizing a forced (or mechanical) draft moves a signifigant amount of air. an OAK allows this air to be pulled from outside the dwelling and redeposited outside after combustion and venting. this ensures first off that there is ample combustion air present for efficient complete combustion.

not using an OAK can result in the following scenarios; negative pressure, caused by the house (especially in newer construction where new housebuilding technologies such as housewrap ,newer better sealing windows and doors, etc. can make a house tight enough that in some cases a definate negative pressure buildup can happen,remember the stove isnt the only exhausting device in the home , clothes dryers for instance remove a large quantity of air , bathroom vents , range hoods etc.

now the benefits from having an OAK in a drafty old house are present as well, if using house air , you are sucking heated air (that you have already burned fuel to heat mind you)through the stove and dumping it outside, lower efficiency. now going back to the beginning of my post, note the basic physics, "and the void left by its departure must be filled..." this replacement air will be whistling through every crack and crevasse in the structure, this mind you is cold air that you must pay to heat just like you paid to heat the departing air, in essence , heating the "same airspace" multiple times, less efficient.
ok, that said , think about another physical law, air when heated expands. if you keep the same air in the house using an OAK and heat it , the pressure in the house must rise slightly, which creates positive pressure , that will in turn push against the very leaks that the appliance would normally be sucking air into the structure through. more efficient.

zero pressure plane;every structure with a roof that has even moderate resistance to rising air will have somewhere within it a zero pressure plane. warm air rises (just like in a chimney)except when it hits the ceiling its trapped there at least temporarily until it can leak out. the trapping of the heated air raises pressure.
consequently the lower in the house, where the heated air has left becomes lower in pressure (providing its not a complete sieve) so somewhere between the two is the zero pressure plane ,which is where the ambient air pressure inside is the same as outside. a stove located below this plane will not perform as well as it would with the same chimney if it were above the plane. this is why its often trickier to get a woodstove(especially a newer phase2 stove) started from cold in a basement. an OAK makes this irrelevent as the outside pressure where the flue is dumping into would be the same as the pressure from which the intake air is coming. this is why harman made the comment in their manual about installs on lower floors.

smokebacks; first of all, any pellet stove can smoke back. in a negative pressure environment it can happen more readily especially in cases of power outage or mechanical draft failure (especially early in the fire before the vent heats up and picks up a small draft from convection) having outside air eliminating the negative pressure reduces the odds of smokeback or smoke release in the dwelling (trust me folks , smoke in houses is not somthing a manufacturer wants to hear about) i'd be remiss if i didnt mention that a well maintained frequently cleaned unit is less likely still to suffer this malady (gasket maintenance folks!)

essentially the manufacturer (Harman in this case) is not urging you to do this so they can sell you another kit (heck we give one away with every pellet and biomass stove we sell at ESW) they want you to enjoy the full capabilities of their product , and certainly as we do , want to lessen the possibility of a bad experience with their product. personally i think an OAK should be mandatory with any pellet stove in a residence. it cannot hinder performance (the arguement about the air being colder so it doesnt heat up as much is pretty well debunked) granted some applications do not lend themselves easily to an OAK install. but if you can do it especially if its a simple application , do it.

 

[stoveguy2esw]

u didnt read my prior post on fresh air venting, u aint answered smoke analysis which should include at this point how much excess air is involved in burning your p stoves by smoke analysis of course, & i tried to pm u the last link on my sig. from lopez labs with their pretty page....anywaze ... :kiss:

i am going to be in my office for a while starting tomorrow , my office is at the north plant location , my lab is in the south plant annex, corie's lab is at the north plant ,. so....... i should see him this week , i'll ask again if he has had a chance to pull those numbers.

 

[doghouse]

I opened up your Lopez link. What am I looking at?

 

[tjnamtiw]

:question: hh:

epa recomends 1/3 volume air exchange per hour minimum to avoid inside air pollution= cant live in a plastic bag

So, for a 3000 square foot house with 8' ceilings, that's 24,000 cubic feet. 1/3 of that, or 8000 cubic feet, has to be exchanged every hour.. That's 133 CFM that has to 'leak' into the house. How many CFM does the usual combustion blower flow?

From my earlier post, does anyone use an OAK up their chimney for an insert? I'll ask the same question over on iburncorn.

 

[jtakeman]

From my earlier post, does anyone use an OAK up their chimney for an insert? I'll ask the same question over on iburncorn.

A buddy of mine has an insert, He installed without an OAK. He notice drafts from his slidding door he didn't have(or notice anyway). We installed an OAK and he doesn't notice the draft anymore.

Really it's a personal choice. You can try with out it first. But if there seems to be drafts that we not there before. Install an OAK.

jay

 

[smoke show]

.

 

[tjnamtiw]

:question: hh:

epa recomends 1/3 volume air exchange per hour minimum to avoid inside air pollution= cant live in a plastic bag

So, for a 3000 square foot house with 8' ceilings, that's 24,000 cubic feet. 1/3 of that, or 8000 cubic feet, has to be exchanged every hour.. That's 133 CFM that has to 'leak' into the house. How many CFM does the usual combustion blower flow?

From my earlier post, does anyone use an OAK up their chimney for an insert? I'll ask the same question over on iburncorn.

sounds right & i think im right about the 1/3 figure. house still aint airtight unless inside a plastic bag but modern construction tends to be lots tighter
4u---1 cubic foot of 70*f air replaced by 1cf of 20*f air loses .6btu.

So, I believe that an OAK would probably be the best solution for consistent stove operation, but the argument about lost heat is not so clear since the 133 cfm cited above has to come from somewhere so it might as well be the combustion blower using room air.

 

[Romy]

about time they did, we have required it for several years.

...this air once it passes through the fire leaves the stucture. this air has to come from somewhere and the void left by its departure must be filled or a vacuum will result.basic physics.

+1

can't argue with physics

 

[watrskir]

From my earlier post, does anyone use an OAK up their chimney for an insert? I'll ask the same question over on iburncorn.[/quote]






I also have an insert, in a chimney, in the center of the house and think it will be difficult to vent through the cimney. I guess an otion would be to go down the ash cleanout in the fireplace to the basement and out a wall?? But i believe the ait intake on my quad classic bay is on the right side closer to the front. How would I attach an oak and run it to the back of the stove down my cleanout and to an outside location and have it look decent??

 

[watrskir]

quoted from stoveguy...."i'd be remiss if i didnt mention that a well maintained frequently cleaned unit is less likely still to suffer this malady (gasket maintenance folks!)"




Sorry I probably should have started a new thread on this but what is required for gasket maintanance on a stove besides vacuuming of the ashes



still havent figure out how to properly quote someones comments