more air or less air = hotter

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chrisasst

Minister of Fire
Aug 13, 2008
1,289
cortland ny
Still confused on this. According to my manual, the more air I give the fire, the hotter it is supposed to get. However, the more air I give, seems the cooler the stove gets.... if I give less air, it seems to get cooler also...so I don't know...
So what should happen when more air is given, or what happens when less air is given.
 
Too much draft and most of your heat goes out the vent, but too little air = incomplete combustion aka soot and creosote.
 
The setting between too much and too little is the sweet spot! This is where you want to run your stove for best performance!
 
Maybe its just me but i noticed that i have to adjust the airflow depending on the brand/type of pellet i use.
 
We all struggle to hit that sweet spot.

I have the problem with my lopi of playing with 3 variables.

Pellet Feed
Blower Fan Speed
Dampener Opening

I have it figured right to make my house HOT when I want, but am working on it to get the best efficency.
 
livefreeordie said:
Maybe its just me but i noticed that i have to adjust the airflow depending on the brand/type of pellet i use.

Nope, that is to be expected if you have no means to do a feed trim.

Pellets vary in density, that means that any given fuel charge dumped into the pot also varies by weight. More fuel (denser pellet) requires more air to be burned in same amount of time as a less dense pellet (less weight per fuel charge) does.

Some stoves allow both feed and air trim, those stoves can usually burn even marginal pellets.
 
This could be a dumb question, how do I know which pellets are dense and which ones are not.
 
chrisasst said:
This could be a dumb question, how do I know which pellets are dense and which ones are not.

You get a measured container, which you fill with several samples of what you are planning on burning. You weigh each container full, then subtract the weight of the container.

Add all of the net weights and divide by the number of samples. You now have the number you need to compare to other pellets with in order to determine which pellets are the denser ones.

Sample each pellet brand you have and then you can rank them in terms of density. The higher the weight the more dense the pellet is.
 
Cubex is a dense pellet. The stoves we run them in all had to have the air flow turned up and one stove the only solution was to turn the pellet feed down to get the best burn.
 
You will be hard pressed to say what the sweet spot for the stove you have is by preset measures. And density is not the real measure wither. Forty pounds is forty pounds, the density is only a measure of volume. . The same volume of dense pellets will have more BTU's than the same volume of less dense pellets. The BTU's from many softwood pellets is higher than hardwood ones, and they are typically less dense.

The ideal burn can be viewed as the point at which maximum air is passed over the pellets to grab the heat and transfer it to the heat exchangers. Some heat has to go up the flue to carry the exhaust gasses. All owners manuals talk about an active flame, not a lazy one. Sometimes it is described as just short of a blow torch, but there is a point of diminishing returns. Too hot, too active a flame and too much air will literally blow the pellets out of the burn pot. The sweet point to me is the one where the flame is at it's peak and the pellets do a little Irish jig in the burn pot.

Fishsniffer and I have stoves that we control the action. Many have burn pots connected to digital allocators that control the action. Personally, I like to tweak my stove, not my phone.
 
I don't believe I can adjust the air on my Harman PF100
 
littlesmokey said:
And density is not the real measure wither. Forty pounds is forty pounds, the density is only a measure of volume.

With an anology stove you could believe this, But with todays digital stoves were the feed rates are preset and the user has no control over them. I think not. The auger feeds volume not weight into the stove. Density and size effect the volume of said fuel charge. Damper air alone may not be enough to comp for these very dense perfectly size fuel that may over power said digital limited control. Hard to tweak what you can't because stove manufacturers have taken away. They have tried to make them idiot proof just a bit to much IMHO.

If you don't believe density has an effect on the amount of fuel fed to the burnpot? Try feeding straight saw dust to your dragon's.
 
j-takeman said:
littlesmokey said:
And density is not the real measure wither. Forty pounds is forty pounds, the density is only a measure of volume.

With an anology stove you could believe this, But with todays digital stoves were the feed rates are preset and the user has no control over them. I think not. The auger feeds volume not weight into the stove. Density and size effect the volume of said fuel charge. Damper air alone may not be enough to comp for these very dense perfectly size fuel that may over power said digital limited control. Hard to tweak what you can't because stove manufacturers have taken away. They have tried to make them idiot proof just a bit to much IMHO.

If you don't believe density has an effect on the amount of fuel fed to the burnpot? Try feeding straight saw dust to your dragon's.

Hmmm??? Is that a concession to us old fashioned stove tweakers? Manual means using your head, not the presets. :cheese:
 
littlesmokey said:
j-takeman said:
littlesmokey said:
And density is not the real measure wither. Forty pounds is forty pounds, the density is only a measure of volume.

With an anology stove you could believe this, But with todays digital stoves were the feed rates are preset and the user has no control over them. I think not. The auger feeds volume not weight into the stove. Density and size effect the volume of said fuel charge. Damper air alone may not be enough to comp for these very dense perfectly size fuel that may over power said digital limited control. Hard to tweak what you can't because stove manufacturers have taken away. They have tried to make them idiot proof just a bit to much IMHO.

If you don't believe density has an effect on the amount of fuel fed to the burnpot? Try feeding straight saw dust to your dragon's.

Hmmm??? Is that a concession to us old fashioned stove tweakers? Manual means using your head, not the presets. :cheese:

Yep! You must not have any experiance with these new fangled digital stoves. On most the board controls the feed rate for each heat setting, The user cannot adjust the feedrate in said heat range. Some stoves have feed trim, That allows slight adjustment. Some of the new fangled contraptions don't even allow for damper adjusment. Again just slight trim rates. There trying to make them idiot proof. Its got nothing to do with manual operation! There taking that away little by little! Before you know it you will have to be NFI cert to change the heat level/setting! :roll:
 
j-takeman said:
... There taking that away little by little! Before you know it you will have to be NFI cert to change the heat level/setting! :roll:

That, Jay, will be a cold day in hell. I don't need no stinkin' certifications.

Chris,

You can get a much hotter flame (FIRE) by giving it tons of air, however depending upon your venting it may just send the heat up the flue and outdoors. You can also reduce the air and have a fire that is a darker orange (cooler fire) and actually have much more heat come out the convection air system.
 
SmokeyTheBear said:
j-takeman said:
... There taking that away little by little! Before you know it you will have to be NFI cert to change the heat level/setting! :roll:

That, Jay, will be a cold day in hell. I don't need no stinkin' certifications.

Chris,

You can get a much hotter flame (FIRE) by giving it tons of air, however depending upon your venting it may just send the heat up the flue and outdoors. You can also reduce the air and have a fire that is a darker orange (cooler fire) and actually have much more heat come out the convection air system.

I have tried to pull the damper out from 1/8" ( orange lazy flame) pellets build up but no more heat. and tried to open it 2" ( short airy flame) and I can watch the heat go right out the vent. The best spot for me is 1" it seems but the pellets to me still burn down way to fast..
but then after the pellets build up, I open the air more I can get more heat then, but can't keep doing that
so I don't know..
 
chrisasst said:
SmokeyTheBear said:
j-takeman said:
... There taking that away little by little! Before you know it you will have to be NFI cert to change the heat level/setting! :roll:

That, Jay, will be a cold day in hell. I don't need no stinkin' certifications.

Chris,

You can get a much hotter flame (FIRE) by giving it tons of air, however depending upon your venting it may just send the heat up the flue and outdoors. You can also reduce the air and have a fire that is a darker orange (cooler fire) and actually have much more heat come out the convection air system.

I have tried to pull the damper out from 1/8" ( orange lazy flame) pellets build up but no more heat. and tried to open it 2" ( short airy flame) and I can watch the heat go right out the vent. The best spot for me is 1" it seems but the pellets to me still burn down way to fast..
but then after the pellets build up, I open the air more I can get more heat then, but can't keep doing that
so I don't know..

The feed from the stove isn't perfect. At times you will have a pot full of burning fuel with a large flame and at other times you will have a pot that is almost empty unless you run on a higher setting. This is because the burn pot receives the fuel in inconsitent doses.

In your case it appears you need less combustion air.

This will slow the rate of burn of the fuel and lead to a better average flame that will maintain better height and thus heat between doses of fuel.
 
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