flue heat extraction

[CrappieKeith]

theoretically, extracting flue heat means you would be cooling the gases in the flue, thereby creating a cooler surface for creosote to adhere to.

in other words, you'd be making your flue load up with croesote.

Exactly....
Also if your having too high of flue gas temps I'd be looking at other ways to slow down draft speeds to create longer burn times....giving your wood heater time to exchange the heat is critical...then again some people use screw drivers for hammers.

Adding Magic Heat for a heat remover has proven to me not a good choice.We had one as a kid and I recall the flue always loading up.

 

[Phil_Marino]

Exactly....
Also if your having too high of flue gas temps I'd be looking at other ways to slow down draft speeds to create longer burn times....giving your wood heater time to exchange the heat is critical...then again some people use screw drivers for hammers.

Adding Magic Heat for a heat remover has proven to me not a good choice.We had one as a kid and I recall the flue always loading up.

You're right, Crappie - one way to lower flue gas temperatures is to slow down the rate that you're burning wood. Of course, another way would be not to burn any wood at all.

The problem with limiting burn rate is that you also limit the useful heat that the stove produces. There are times ( for example, -10F outside and blowing) that I need to keep my stove burning fast and hot to keep the house warm. Under those conditions, it really helps to extract some heat from the stovepipe ( and, does not promote creosote formation). The important thing is to only extract extra heat when, by doing so, you won't be cooling the flue gasses below 250F or so.

I have no experience with Magic Heat, and it may cause problems, but that doesn't mean that extracting flue heat - under the right conditions - is not a good approach, if you're careful not to cool down the flue gasses too much.

Phil

 

[ray benson]

I had a Ben Franklin stove in the late 1970's .That magicheat would have been a good application. Now with an epa stove it's critical to burn dry wood and keep the flue temp up. Wouldn't even consider a magicheat for the newer woodstoves.

 

[CrappieKeith]

You're right, Crappie - one way to lower flue gas temperatures is to slow down the rate that you're burning wood. Of course, another way would be not to burn any wood at all.

The problem with limiting burn rate is that you also limit the useful heat that the stove produces. There are times ( for example, -10F outside and blowing) that I need to keep my stove burning fast and hot to keep the house warm. Under those conditions, it really helps to extract some heat from the stovepipe ( and, does not promote creosote formation). The important thing is to only extract extra heat when, by doing so, you won't be cooling the flue gasses below 250F or so.

I have no experience with Magic Heat, and it may cause problems, but that doesn't mean that extracting flue heat - under the right conditions - is not a good approach, if you're careful not to cool down the flue gasses too much.

Phil

Good point Phil....
However leaving it up to the home owner as to when to operate it is asking a bit much.
I deal with the public everyday...some follow directions and others seem to think common sense over rules the manual directives.

I know it may be asking a bit much ,but there are many stove owners that really need furnaces and they try to crank up their inadaqute stoves to provide more heat than what the unit can provide or distribute throughout the home.
Buying the tool for the job is what I see the real answer....yet for some no $$$ or no ducting or they did not get educated prior to the purchase and now they are stuck with what they have and they are trying to make the best of it.

Some stoves do very well in certain situations.

 

[pook]

Good point Phil....
However leaving it up to the home owner as to when to operate it is asking a bit much.
I deal with the public everyday...some follow directions and others seem to think common sense over rules the manual directives.

I know it may be asking a bit much ,but there are many stove owners that really need furnaces and they try to crank up their inadaqute stoves to provide more heat than what the unit can provide or distribute throughout the home.
Buying the tool for the job is what I see the real answer....yet for some no $$$ or no ducting or they did not get educated prior to the purchase and now they are stuck with what they have and they are trying to make the best of it.

Some stoves do very well in certain situations.

gotta like a furnace salesman scientifically avoiding the issue & dropping a salesline! especcially when the yukon may have a secondary air intake, thru the oilgun, which cools flugas

 

[CrappieKeith]

gotta like a furnace salesman scientifically avoiding the issue & dropping a salesline! especcially when the yukon may have a secondary air intake, thru the oilgun, which cools flugas

Avoiding the issue...let's go there.
Our Eagle wood/oil or wood/gas had some air(small anount the flows through the burner)to keep the smoke from gathering around the nozzles or orifaces and coating them with soot. This was a huge issue with other older model wood/oil units from other manufactures across the industry back in the late 70's and 80's.

The way the Eagles are set up with a manometer is to dial them into .03" of water column. At this speed you will have a flue gas temp that hits 400 degrees when being asked to fire up and around 300 when asked to rest.
So therefore we do not see excessive creosote due to cold flue gas emmisions.
To add inshot style burners have air adjustments on them as they need air to mix with liquid fuel for proper combustion.
With the adding of higher pressures like 100 psi the oil burner burn near as clean as gas furnaces with near zero to trace smoke for emmision as tested with bachorack testing devices.

All of this is as per Underwritter Labs...I have also had a infra red lazer to determine these same numbers in some testing we have done over this past decade.

Nice try.....anything else:deadhorse:

Getting back to the OP's post. Magic Heater's can take heats from the stack. The question is once the tubes start to coat with creosote & cleaning becomes a chore. Then they start on fire because they are too hard to clean.
Maybe a bigger stove may be some help.Something that you can dial down but still take a ton of heat from because it has more thermal mass and more heat exchange surface area built in it.

To the OP....you may have to live with what you have ...if so be real carefull and do not take it for granted that all is right in the world.If you can keep the flue and MH clean then you'll be alright I'd imagine.
All products have limitation to some extent. Knowing these limitation and operating the product as per spec to manuals is the best you'll be able to operate in a safe manner.

 

[pook]

Avoiding the issue...let's go there.
Our Eagle wood/oil or wood/gas had some air(small anount the flows through the burner)to keep the smoke from gathering around the nozzles or orifaces and coating them with soot. This was a huge issue with other older model wood/oil units from other manufactures across the industry back in the late 70's and 80's.

The way the Eagles are set up with a manometer is to dial them into .03" of water column. At this speed you will have a flue gas temp that hits 400 degrees when being asked to fire up and around 300 when asked to rest.
So therefore we do not see excessive creosote due to cold flue gas emmisions.

All of this is as per Underwritter Labs...I have also had a infra red lazer to determine these same numbers in some testing we have done over this past decade.

Nice try.....anything else:deadhorse:

what do u use to stabilize the draft? a barometric damper? & why

 

[CrappieKeith]

what do u use to stabilize the draft? a barometric damper? & why

All conventional furnaces typically have BDR's in the flue.A natural draft is normally around .08"of water column.To help control an oil burner's efficiency
a barometric draft regulator is installed and set with a manometer.Of course the air setting on the burner also has some to do with efficieny.

We use the very same BDR's the the other oil co's use. It just so happens that a wood fire does not need to burn as fast as it wants too in order to make all of the btu's in a lb. of wood or coal.

By slowing down the air we can make all of the btu's and by doing this give the huge amount of heat exchanger surface area time to exchange the heats that are made.

Also by slowing the burn rate down we are also running a cooler fire which is not capable of over heating firebox walls(steel) causing them to split. UL said that in 75 tests the firebox walls never got over 930 degrees.It takes heats much hotter to warp and split steel.

 

[pook]

All conventional furnaces typically have BDR's in the flue.A natural draft is normally around .08"of water column.To help control an oil burner's efficiency
a barometric draft regulator is installed and set with a manometer.Of course the air setting on the burner also has some to do with efficieny.

We use the very same BDR's the the other oil co's use. It just so happens that a wood fire does not need to burn as fast as it wants too in order to make all of the btu's in a lb. of wood or coal.

By slowing down the air we can make all of the btu's and by doing this give the huge amount of heat exchanger surface area time to exchange the heats that are made.

Also by slowing the burn rate down we are also running a cooler fire which is not capable of over heating firebox walls(steel) causing them to split. UL said that in 75 tests the firebox walls never got over 930 degrees.It takes heats much hotter to warp and split steel.

ya but dont the barodamper introduce a cooling on the fluegas similar to a Magic Heat?

 

[CrappieKeith]

ya but dont the barodamper introduce a cooling on the fluegas similar to a Magic Heat?

Not if you use a manometer to set the speed properly.Speed and temps equate to each other.
With no flue speed control you get into what the OP's issue is....too much heat escaping out the flue....hence adding the Magic Heat to reclaim some of the heats going up the flue.
The problem is that it's too hard to control on an automatic setting causing excessive creosote from time to time which can cause flue fires.
That's why it is so imperative to real be anal about how and when it is used and that it is kept clean.

I hope your getting this Pook cause I'm getting exhausted running around this bush.

 

[pook]

Not if you use a manometer to set the speed properly.Speed and temps equate to each other.
with no flue speed control you get into what the OP's issue is....too much heat escaping out the flue.

I am the OP!

 

[CrappieKeith]

My bad...I musta got lost in all of this....do you understand.

You can always call me so we can get into more detail.

 

[CrappieKeith]

...too add our furnace are UL listed as safe with BDR's. I did not see that Magic Heat was a UL listed product.

 

[laynes69]

The more draft that a chimney produces, the more the damper has to open. The more the damper opens, the cooler the flue gasses. I had some glaze in the flue pipe right after the baro, but a thin layer of dust in the main chimney. When I measured flue temps on the external surface of our flue, the temps were at least 100 degrees less after the baro. Luckily our furnace has a high combustion efficiency so we see very little in the flue. Without it, we would be in trouble. I have eliminated our baro for now and are using a key damper and a manometer to verify draft. Still after over a month of burning and nothing in the chimney, I have nothing to worry about.

 

[pook]

The more draft that a chimney produces, the more the damper has to open. The more the damper opens, the cooler the flue gasses. I had some glaze in the flue pipe right after the baro, but a thin layer of dust in the main chimney. When I measured flue temps on the external surface of our flue, the temps were at least 100 degrees less after the baro. Luckily our furnace has a high combustion efficiency so we see very little in the flue. Without it, we would be in trouble. I have eliminated our baro for now and are using a key damper and a manometer to verify draft. Still after over a month of burning and nothing in the chimney, I have nothing to worry about.

interesting! key damper aint as automatic as barodamper or MH. Taxidermist @ Hearth had a barodamper setup which avoided the creo...FYI

 

[logbutcher]

My bad...I musta got lost in all of this....do you understand.

You can always call me so we can get into more detail.

Not your "bad" at all. Your chain is being yanked CK.....big time. This guy has online history.

Now, watch the . He ran out of meds.

You're being too nice, too rational, too intelligent.

 

[myzamboni]

I did warn.

 

[pook]

Yukon has a firebox & a secondary heat exchanger I see. so the fire burns & the smoke travels thru a set of tubes in a second chamber, the tubes are cooled by a fan so to provided heat for the house.
woodstove has a firebox & an added heat extractor [MAGIC HEAT] . so the fire burns & the smoke travels thru a set of tubes in a second chamber, the tubes are cooled by a fan so to provided heat for the house.
similar? so whats the diff? should i add a barodamper above the MH to make the 2 systems exactly the same?
draft regulation with a barometric damper requires no electric but sucks out room air. MH requires electric but sucks out no room air.......both will regulate the fire though the baro will do so more effectively--I currently have a MH on my sawdust burner to keep the system from overheating & it turns on & off as the MH thermostaT TELLS IT TO.....duh
http://www.yukon-eagle.com/FURNACES/EAGLEIHUSKY/HEATEXCHANGER/tabid/103/Default.aspx

 

[pook]

Yukon has a firebox & a secondary heat exchanger I see. so the fire burns & the smoke travels thru a set of tubes in a second chamber, the tubes are cooled by a fan so to provided heat for the house.
woodstove has a firebox & an added heat extractor [MAGIC HEAT] . so the fire burns & the smoke travels thru a set of tubes in a second chamber, the tubes are cooled by a fan so to provided heat for the house.
similar? so whats the diff? should i add a barodamper above the MH to make the 2 systems exactly the same?
draft regulation with a barometric damper requires no electric but sucks out room air. MH requires electric but sucks out no room air.......both will regulate the fire though the baro will do so more effectively--I currently have a MH on my sawdust burner to keep the system from overheating & it turns on & off as the MH thermostaT TELLS IT TO.....duh
http://www.yukon-eagle.com/FURNACES/EAGLEIHUSKY/HEATEXCHANGER/tabid/103/Default.aspx

xcuse my bump= CK has chosen to ignore this. secondary heat exchanger as from Yukon is no different from addition of MAGIC HEAT to a woodstove! if so , how?

 

[jags]

Pook - Leave these nice people alone. Your logic of using a magic heat on a properly operated EPA stove is flawed. A PROPERLY operated EPA stove DOES NOT have excess heat to extract without the possibility of dropping the stack temp to dangerous, creosote producing temps.