Never Burned Coal Before...Advice?

jschaefer7406 wrote:This uses a heat exchanger and convection blower to send the heat through the ductwork into the house. Blower is running non-stop, but I imagine that's normal with a standard mechanical fan/limit control. Hope that answers your question

With the blower running non stop it means that the stove is putting out heat faster than the blower can remove it. The fan/limit control is set to turn on the fan when the heat in the plenum reaches whatever temperature the control is set at and to turn off the fan when the temperature falls below that setting to avoid blowing cold air. There is a differential which you can set. The limit part does not function since the furnace is manually controlled. There is usually a switch to turn on the blower manually which I assume you are not using, but letting the blower run automatically controlled by the fan control.

Anything you can do to make the blower more efficient in removing the heat from the furnace will lower stack temperature and put more of the heat into the house. How is the cool air from the house getting back to the furnace? One picture shows what looks like a return at the base of the coal furnace. The size of a return should be at least the size of the feed duct. It really should be connected to the return duct for the house. Failing that, the existing return to the oil furnace should have an opening so that the coal furnace can pull the cold air from the house.

How warm is the basement? You could be losing a lot of heat there. Another picture from further away showing the complete coal furnace and piping would help. Don't forget to oil the blower motor and fan bearings if so equipped.

What franco b said about the limit switch and contiuous fan, unless the switch has failed. Remember it was submerged in flood water.

If I read a previous post right Joe is burning 80 to 100 pounds of coal per day to heat 1500 sq ft. I burn 25 to 50 pounds per day to heat 1200 sq. ft. in an old drafty but insulated house. I think mathmaticaly it is safe to say Joe is burning way more coal than he should have to. Either his furnace is ineficient or his house is loosing excess amounts of heat. a steady 250* stack temp. seems a little high.

Joe, When your furnace has a fire in it can you lay your hand on the outside of it comfortably? Just because it has ductwork to the upstairs doesn't mean it isn't also heating the basement through convection if the furnace is not insulated properly.
If your house is not insulated then that and not the furnace could very well account for the high coal consumption.

Best of luck.

franco b wrote:Anything you can do to make the blower more efficient in removing the heat from the furnace will lower stack temperature and put more of the heat into the house. How is the cool air from the house getting back to the furnace?

Hello again,

Thanks for the replies guys. As for the blower, it is much smaller than the blower on my oil burner. Direct driven, the cage is only approx. 8". It is being fed through a 16X20 duct with a filter drawing from the basement. I know this isn't ideal, but the cold air return was removed when the ThermoPride was installed in '04. I plan to reun a cold air return duct to it, but for now have been leaving the basement door cracked so it can draw freely. The fan/limit settings also may not be correct, believe the off setting is 90 or 100 (on is 110 or 120, have to check). Is a coal furnace really going to get cool enough to bring it down that far?

With the recent night time lows, I am having some trouble getting the house above 66-67 in the morning. To confirm what Grixxly was saying, I know my house likely isn't insulated (built in 1890's) and the furnace may not be the most efficient. My only concern is burning the coal as efficiently as I can given the current circumstances. If it's only gonna get as good as 80-100lbs per day, so be it. I just wanna make sure it's the house and such and not something I'm doing wrong ...

My biggest bother at this point is wondering whether or not I have the baro set right. As said previously, I checked it against a manometer and verified that the numbers on the baro ARE actually accurate. Set it to .04" and it worked great for a few days (house consistently was 72, bottom draft 1/4 open). Now wondering it .04" is too low for the colder temps we have now though (low teens), because even with the bottom draft now open 1/2, I am still only seeing 66-67 in the house. Seems like opening the draft doesn't really change the tempo in the house (yes, I am waiting 30 minutes to an hour ). Increased the baro setting to .06", we'll see what happens. Thoughts?

Also wondering if maybe the Mrs. isn't shaking it down enough at night when I'm working. I usually shake until the whole ash pan area is glowing brightly and a few embers are falling. Is this right, or am I shaking to little or too much?

Thanks for bearing with me guys,

Joe

I don't like cracking the basement door for a return. Remember you need at least the area of the feed. Why not cut a hole in the existing return and let the coal furnace pull across the floor of the basement. It would eliminate all the drafts upstairs from the cold air having to scoot across your living floors and make things more comfortable. Any hole you make can be easily patched if necessary.

You can't judge how well the coal furnace is working by how the house is heated; you can only judge at the furnace itself. What is the temperature of the furnace sides and top and also the stack temp.? If around 600 degrees on top and sides then you are already pretty close to the max. and need to concentrate on distribution. A good size blower could be mounted on the floor right at the return opening and sealed with duct tape. Your existing 8 inch blower I don't think is cutting it. For now try putting a box fan or whatever you have blowing into the return of the furnace and see if it makes a difference.

It would seem to me that the blower should be sized to the furnace as I would assume this is factory made. How is the air flow at the registers in house with the blower running? Also looking at the picture that showed the fan switch it appeared to me that the on/off points were close.

jschaefer7406 wrote:The fan/limit settings also may not be correct, believe the off setting is 90 or 100 (on is 110 or 120, have to check).

I run mine about 50*-60* apart, right now I have them set to come on at 200* and off at 135*(these numbers are just reference points and may not be accurate
degree settings) I would try 125 off 175 on and see what happens. In my setup if the air coming out of the registers is less than 90* I won't gain much heat upstairs.If the on setting is too high it will take too long for the blower to come on and the house will cool off, set to low the blower will cycle too frequently. This took A while to find the sweet spot.
Hope this helps.

I would agree with "Jst a Vtr" on the fan limit switch. I have mine set to the standard 100* off, 150* on and max 200* (which is the preset). When my Themopride wood furnace hits 200* at the plenum, then it shuts the front damper regardless of whether the thermostat is calling for heat. Make sure this is working according to the manf. settings. I would definitely work towards getting the cold air return set up.