Normal Coal Consumption?

Is the combustion blower set to come on by call of a thermostat? I'm not a fan (no pun intended) of combustion blowers. I think the coal does its best work when left to run steady and not continually revved up then left to cool down by a combustion blower..

Natural draft, a barometric damper and running a pressure of -.03 to -.05 will make best use of your coal. Steady consistent draft pressure will result in steady consistent heat output

Plus it seems that a combustion blower pushing against a manual pipe damper could result in a positive pressure situation in the fire box which means it would leak CO into the living area. Not good..

Yes, based on the experience of lightning in this area, I second that you should try losing the combustion blower.

Lightning wrote:Is the combustion blower set to come on by call of a thermostat? I'm not a fan (no pun intended) of combustion blowers. I think the coal does its best work when left to run steady and not continually revved up then left to cool down by a combustion blower..

Natural draft, a barometric damper and running a pressure of -.03 to -.05 will make best use of your coal. Steady consistent draft pressure will result in steady consistent heat output

Plus it seems that a combustion blower pushing against a manual pipe damper could result in a positive pressure situation in the fire box which means it would leak CO into the living area. Not good..

combustion blower is supposed to come on via T-stat, BUT the relay broke awhile ago, so its just stuck on all the time, however I can just set it at a speed and she stays constant. With this furnace I would have to leave the ash door open all the time to get a full-natural draft up through the coal bed properly, setting the blower at low speed should do just fine, as it can feed a gentle flow of air directly into the coal bed.

no barometric damper on the flue, ill just have to put my manometer on it and play with the manual damper to achieve .03-.05" WC.

thanks for the advice guys, ive burned a little coal before a couple years ago, but this is the first time we are running solely coal for a long period.

50-70# a day at a medium high heat. Probably need to shake and load 2X a day.

Ok so today im getting really close to dialed in...Last night around 1030 I loaded about 20lbs, this morning at 700am topped it off with another 20lbs and turned the air way down, since nobody is home all day...now at 700pm its been cranked up for a few hours since coming home from work, and still doesnt need to be topped off, very impressed with the burn duration of coal. If I was burning wood id be lucky to get 8hrs out of a pack-full load.

I burn 32 lbs a day with a Morso 1410 squirrel. Some days its nearly 35 others its closer to 30 but it almost always averages out to 32 lbs a day...not that I keep track of it and am ridiculously anal about how much coal I purchase and how long it will last.

Its a small stove though...just 30K BTU.

titleist1 wrote:if you don't have an owners manual, i'd shoot for .04 on the draft in the flue pipe to start, make sure you are not pressurizing the firebox with the combustion fan blowing too much air in there.

Temps are going to be really different depending on stove / weather / house / etc. The stove temp will tell you how intensely to fire the stove to get the house comfortable in different weather, you should have an idea from burning wood what a good target temp is to start with. The flue / stove temp differential will tell you how efficient you are with your burn. flue temp should be less than half the stove body temp, for example, this morning my stoker was at 680* above the door and 230* on the stack measured with an ir temp gauge before the baro. after the baro it was 155*.

I will finally be switching over to coal this spring. The current reading on my woodstove is top 700 stack surface 300 and stack probe 525 this with single wall pipe Rutland magnetic thermometers on stove surface front center, and stack pipe 10 inches of outlet. The probe is in the center of stack pipe at 18 inches of outlet. This is with about a total of 11 to 12 ft of pipe from stove to chimney cap I would think about the same as any other single story house with stove in living area. Does these numbers sound about what to shoot for on a 14 degree morning like I have today?

For wood burning that is probably in the ballpark although I think you are sending too much heat up the chimney which probably indicates a draft well over .05. Maybe an MPD would help (if you aren't already using one).

In addition to the CO monitors and temp gauges that we always recommend, having a manometer connected to your stove is a great tool for dialing in the settings as well as being used as an early indicator of fly ash build up in flue pipes.

When you burn coal you will be able to use an MPD or a barometric damper. This will help control the draft through the coal bed to about .04. Your stove temp and stack temp will then be much further apart.

titleist1 wrote:For wood burning that is probably in the ballpark although I think you are sending too much heat up the chimney which probably indicates a draft well over .05. Maybe an MPD would help (if you aren't already using one).

In addition to the CO monitors and temp gauges that we always recommend, having a manometer connected to your stove is a great tool for dialing in the settings as well as being used as an early indicator of fly ash build up in flue pipes.

When you burn coal you will be able to use an MPD or a barometric damper. This will help control the draft through the coal bed to about .04. Your stove temp and stack temp will then be much further apart.

Your IR gun measures skin temp of the pipe just like the magnetic thermometer that sticks on. It has been documented over at Hearth.com a wood burners site a lot like this is for coal. I think if you used a real stack thermometer you will find the flue gases are much hotter than your IR gun is telling you. At the inside skin heat is transferred to the pipe that radiates about half of it away. There is about a half inch of boundary layer of cooled flue gases from this effect. To prove this to myself a friend brought over his IR gun to double check what others have said it it was within 5%.

As far as a huge draft the total height of the chimney would be hard pressed to draw that hard as it is painfully short.

I think the IR (at least mine) is much closer to reality than the magnetic gauges from what I have personally seen. I do have a 2" probe temp gauge on my vertical stack about 12" up from the exhaust port and the reading on the gauge is within 10% of the IR gun and usually runs in the 100* - 230* range from idle to extended full out burn. It is hard to say the gauge is any closer to the IR gun than that because the scale on the gauge isn't very 'granular'. But I am confident the IR gun is within 20* of the flue gas temp based on the probe reading. There is a lag of the skin temp until the pipe gets temp soaked, but when the stoker has been running full out and the probe settles at a temp for a few hours then the IR reading will be that close to the probe. There is very little ash build up on the inside of the vertical to insulate it. It is a much different story on the horizontal flue pipe. The fly ash there can insulate the skin temp on the bottom by about 100* than the top of the pipe. Obviously some of that delta is due to the stratification inside the pipe.

I have a magnetic gauge that I compared to the probe a couple years ago and found it to be way cooler, like half the reading. I guess that was because of the rounded shape of the flue pipe as well as the air circulating behind the gauge against the bi-metallic spring. Again it is hard to be exact on the reading of each (especially the magnetic gauge I used) because of the scale on the gauges. I don't use the magnetic gauge in the house any more, I keep it on the body of the stove in the workshop for comparison to the stack probe out there.

Even with that short chimney, I think you may be surprised if you measured your draft. Mine is only about 18' tall at most and I got up over .1 with my hand fed burning wood & coal in it with no baro or MPD dampers. It would be interesting to see what it measured at different flue temps.

edited to add a couple pics of IR & temp probe although it has been idling since about 9am so it isn't up to its normal full burn temps.

Well I guess it is a we shall see thing. I no doubt could save some wood with a damper but I do not have enough draft to close the air all the way down to get a good secondary burn except on the coldest of days with perfect wood. How hot is your stove top when idling? I assume you have the damper wide open when idling as well or no? I just checked and cracked the door on stove with the probe at 250 and it pulls cigarette smoke in from 5 inches away so maybe more draft than I think.

ddahlgren wrote:How hot is your stove top when idling? I assume you have the damper wide open when idling as well or no?

I missed getting an idle temp on the stove body this morning and since I had the house doors open quite a bit today carrying stuff out to the truck the stoker has been firing the last 2 hours or so. The stack probe temp is up to ~210* (IR 215*), the stove body is at 585*. Maybe the stack probe has a little ash on it and some turbulence around it lowers its reading slightly?

I don't have an MPD only a baro. The baro is set to open at .04 and at idle the draft is usually at .03 so the flapper stays closed.

Get a manometer and measure that draft.....you deserve a new toyol! Manometer, IR gun, etc. They're better fathers day or birthday presents than a tie!!