Stove will not get hot

[Glenn]

When dry seasoned firewood is used as a fuel, this stove needs the chimney cleaned  maybe twice in a heating season. By using a controlled burn in the same wood stove, I was able to show the effects of adding a small amount of coal with each fire. 

 

The dry seasoned wood was all from the same tree, about the same size, and each time the fire was built, the same amount of wood was burned each time. The difference was adding one small shovel full of bituminous coal with each load of wood. The stack temperature was monitored and kept at about 300*F to 350*F to keep the operating temperature of the stove about the same, and above the temperature where creosote would be formed. The ash in the stove was kept at a constant level so it was not a factor.

 

Within only a few fires you could tell the difference as the stove would not act the same with each new fire. It was more difficult to light, and took longer to get started and up to operating temperature. By the time a 5 gallon bucket of coal was used, and even with the air intake holes were now fully open, the stove would struggle to reach the 300*F to 350*F stack temperature. This gave a false sense of security as the stove would reach a temperature limit and not get any hotter. Over all I added about 7 gallons of bituminous blacksmithing coal to the fires over the test period of this project.

 

I kept a visual check on the exhaust from the top of the chimney as a indicator of the combustion. There was the normal amount of smoke at start up (only a few minutes), but once the fire reached operating temperature, there was little or no smoke for the rest of the burn. When wood was added there was a small amount of smoke but this went away as the fire reached operating temperature again.

 

Results

The ash level had been kept constant and there was some charcoal present, a little more than normal but nothing unusual. The inside of the stove was relatively clean indicating a good high temperature burn rate.

 

I disassembled the entire length of chimney in order to clean the pipe. The interior of the chimney from where it left the stove, and for most of the length of the chimney was coated with a soft black fluff. The 6 inch interior diameter pipe was effectively reduced to less then 4 and more like 3 inches of open diameter.  

 

See attached photo

 

The clean section is where the two chimney pipes were joined and is a good indication as to just how much build up of material occurred.

 

Once the chimney was cleaned and reassembled, a fire was built. The same wood ignited with little effort and burned with vigor. In fact the fire burned so well that even with all the air intake holes closed there was a danger of the stove over heating. Based of past fires, I had put a normal (small) starting load of wood into the stove. I failed to adjust and reduce the amount of wood used to start the fire based on a new and freshly cleaned chimney.  Safety measures were taken to bring the fire under control and reduce the stove temperature. I built these safety measures into the construction of the this stove from the beginning. Other stoves do not have this option. 

 

 

Conclusion:

Keep the bituminous blacksmithing coal in the forge. Do not put it in the stove.

 

Keep the fire burning hot to prevent creosote.

Keep the chimney clean and properly maintained through out the heating season.

Always adjust the fire for any changes in the system. You can add a log, but it is difficult and dangerous to remove one if the fire gets too hot.

[Nobody Special]

Interesting. I wonder what kind of results you would get with anthracite heating coal. Or if it would have enough of an updraft to even light well in a wood stove.

[ianinsa]

Wood needs compatativly small  quantities of air to burn if you were to add a small air intake to the chimeny  it would become a reburn chamber , whilst this may  keep the stack clean it may :D not be the smartest move depending on your setup!

all that "gunk"  equates to heaps of BTU's  that you are throwing away all the while poluting  like mad !

 

If you think compatativly using your forge as an example without using the blower  make a fire using dry wood it will s moke a bit to start and then it will burn clean much like your BBQ.  then add just one shovelfull of coal, the result = less than ideal. Now add some air(switch on the blower) and .......Volla!  :

[Glenn]

 Or if it would have enough of an updraft to even light well in a wood stove.

The stove draft works well for burning many fuels that I have tried. I build a bed of coals with wood before the alternate fuel is added.

 

Wood needs comparatively small quantities of air to burn if you were to add a small air intake to the chimney  it would become a reburn chamber , whilst this may  keep the stack clean it may :D not be the smartest move depending on your setup!

all that "gunk"  equates to heaps of BTU's  that you are throwing away all the while polluting  like mad !

 

The air injected into the exhaust stack does indeed act like an afterburner, burning any of the previously unburned volatiles from the fire. The downside is you have fire in your chimney, big time.

 

As mentioned before the only smoke coming from the chimney is at start up. This lasts only a few minutes. After the fire gets to operating temperature there is no smoke coming from the chimney for the remainder of the burn time. The stove is very efficient and most everything is burned completely, leaving only a small amount of ash.

[lcb]

That's an eye opener! :blink:

[Robert Yates]

Man that pipe is clogged bad I would appear the fire was not hot enough to burn the coal efficiently and not have a residue the draft /air ratio seems to be improper to allow the coal to be burned with out a build up .

 

Sam  

[SmoothBore]

A "wood" stove is basically an enclosed hearth.

 

A "coal" stove is fitted with a "shaker grate", that permits the ash to fall away from the burning coal, ... thus enabling full combustion of the coal.

 

While it's feasible to burn wood in a coal stove, ... the reverse is not true.

 

 

 

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