Year 2-Still Freezing

Now that you've made big changes to your system, and your tending patterns and coming to the realization that the warmth of your house is directly dependent on the firebox temperature. I would block that front plate again.

Whatever you do..........only do 1 thing at a time, either remove the plug at the back again, or the Lightning mod and try each one independently.

And to add.........I personally would not use the secondary air on the door. You should get ample over fire air through the opening in the rear plate. As you've found, too much over fire air can slow down the coal...............but then again, this depends on the type of bituminous coal also.

Overfiring and runaway concerns...

Here's a tip:

Keep one bucket of ashes near your stove. If you ever find yourself in need of throttling down your fire quickly and safely, you can shovel a LITTLE bit of ashes on your fire.

NEVER put any water or extinguisher stuff on it. A bucket of ashes should handle whatever fire you have and won't hurt your stove, whereas many of the other options can destroy it rather quickly

Thanks to both of you.
I haven't been too concerned with runaway fires in the past because I've watched it like a hawk.

But I'd like it to stay hotter longer without the risk or the need to check on it so often.

I'll try the back plug first, again, since I'd have to shut the coal off to make the mod and it's supposed to be darn cold for the next few days.

Regarding leaving the louvers open on the load door, I don't know if it makes any more heat (maybe less) but I seem to get a more complete burn leaving finer ash instead of mostly burned baseball sized lumps that look like little meteors

SWPaDon wrote: This tells me that the available air supplied by the spinner must be bypassing the fuel bed through the front and rear plates. It's only when you flood the ashpan area with primary air, by leaving the ashpan door open, that the fuel itself is satisfied.

I like Don's thought process here. It's obvious that the type of coal that you are burning and what I use are much different. What I'm using burns much hotter and longer with the need for little under-fire or primary air.
What you are using may likely need more primary air to keep it burning at a higher temp. Blocking that front liner is easy to do. Even while you have a fire burning. just shove some insulation up from the bottom on either side of the shaker grate nub.

SWPaDon wrote:Whatever you do..........only do 1 thing at a time

A BIG +1 to that!
Don't worry about the plug in the back for now. work on trying to keep the firebed burning hotter longer.If you can keep the fire bed hot then you can consider adding secondary air when refueling to burn off volitales and use that fuel to help heat.

SWPaDon wrote:I personally would not use the secondary air on the door

Don is right here too. You will be getting secondary air from the back liner that is not blocked.
But, in my opinion, if you can get a hot fire bed going some addition of the secondary air should help ignite the volitales that are just going up the chimney un-burned.
It's a balance of heat and air (above and below the fuel/fire) that you need to tune now.
Kind of think of it as almost 2 different fires. The spin control is adding fuel to the bottom of your fire and hopefully keeping it hot much longer. As the coal fire is burning it is releasing gasses (which is more fuel and potential heat) above the the flames. If you have enough heat with those gasses then all you need is to introduce a little oxygen (via the slide control on the load door) and they will ignite. Then you have more heat and less smoke and soot.
But you have to find the balance.
As Don said, work on one thing at a time. Get the bottom fire where you like it first then work on the "over the fire" fire.

Thanks, as always, Ky.
There's no doubt in my mind that we're burning way different coal.


Right now, I started with the plug out of the back.
As far as I can tell (for the second time) that has no effect.

I'll see if I can get some insulation up from the bottom tomorrow.

BTW, that spinner situation was no different when I previously had insulation in there.

As far as experimenting, that's all I've been doing for almost two seasons.

I'm beginning to feel like Edison trying to invent the light bulb.
Trying 10,000 different things.

I have tried the spinner at almost every level (except closed), the top door from closed to 1/2 to full open.

Sometimes I don't think there is a light bulb.

Also, no matter what I've tried, after loading, nothing burns the volatiles off until I poke the pile.
Doesn't matter if I wait 30 minutes or two hours.

Then the fires really burn and lots of black smoke.

Lightning, I have a question about the calculations you did here a couple days ago.

I believed you used 12, 500 BTUs at, optimistically 60% efficiency.

My question (s) is/are:
That is for one lb. of coal?
I'm burning 5 or 10 lbs. at any one time.
Am I not getting 5 to 10 times that output constantly?
And, since my blowers run almost non stop pushing that heat constantly into my house, am I not getting around the same output constantly as opposed to the 72,000 BTUs that are delivered on and off?

Granted, there are losses in delivery for both furnaces

larryfoster wrote:Lightning, I have a question about the calculations you did here a couple days ago.

I believed you used 12, 500 BTUs at, optimistically 60% efficiency.

My question (s) is/are:
That is for one lb. of coal?
I'm burning 5 or 10 lbs. at any one time.
Am I not getting 5 to 10 times that output constantly?
And, since my blowers run almost non stop pushing that heat constantly into my house, am I not getting around the same output constantly as opposed to the 72,000 BTUs that are delivered on and off?

Granted, there are losses in delivery for both furnaces

I gave the furnace 70% in my calculation which could be optimistic. As for the heat output question. My first example for 40 pounds per day..

We'll average the heat output per hour for the coal...
Your coal furnace (and I'll just use some guesstimation numbers) using 40 pounds per day
40 x 12,500 = 500,000 BTU's x .7 (efficiency could be less) = 350,000/24 = 14,583 BTU's per hour

OR you could look at it this way. To burn 40 pounds per day you would average 1.67 pounds per hour right? (since 1.67 x 24 hour = 40 pounds) We can run the equation this way too..

1.67 pounds per hour x 12,500 = 20,875 BTU/hour x .7 (70% efficientcy) = 14,612 BTUs/hour

See, so even though you put on 5-10 pounds at a time or whatever you have to look at the total used over a time period (like a full day) and break it into hours to get your average BTU output to be able to compare it to the propane furnace. Ratings are normally described in BTUs per hour, your propane furnace is rated 80,000 BTUs per hour then we factor normal efficiency loss to get 72,000 BTU per hour.

Thanks for your patient response.

The propane furnace delivers 72, 000 BTUs/hour, correct?
Yet it only runs, maybe, a 5 minute burn every 15 minutes.
For 20 minutes burn, it's only delivering 24,000 BTUs of heat/hour.

1.67 pounds per hour x 12,500 = 20,875 BTU/hour x .7 (70% efficiency) = 14,612 BTUs/hour

Your calculation assumes a constant burn 24 hours a day but it's probably more like 40 lbs. for 16 hours and 10 lbs. for 8 hours overnight.

And those BTUs are constantly being delivered (more or less).

I understand and agree with your idea but, it seems to me, that total delivered BTUs are pretty close.

Does this make any sense?

larryfoster wrote: I understand and agree with your idea but, it seems to me, that total delivered BTUs are pretty close.

Does this make any sense?

Yep, makes good sense. So you average closer to 50 pounds a day which according to the numbers I came up with a few pages ago is over 18,000 BTUs per hour.

So you might ask, why does the propane heat the house better? The propane furnace runs full bore at 72,000 BTUs per hour until the thermostat is satisfied.

I'm still thick, Lightning.

Isn't the gas only delivering 1/3 of those 72,000 BTUs per hour because it may only run 1/3 of an hour and give me heat.
Which is only delivered if the blower runs.

My coal blowers push heat constantly so I'm getting more use of the heat the coal produces.

Granted, it takes a whole hour of running for the coal to deliver it's heat and gas 1/3 of the time.

I'm puzzling about my coal blower.
It apparently isn't able to deliver with the force of the propane blower.

This was alluded to somewhere in this thread.

If I would consider jacking up the coal blowers might that help?
Not sure if I would consider it but wondering if that would help

Is it the amount of heat or the inability to deliver at the same rate

Thanks

larryfoster wrote:Isn't the gas only delivering 1/3 of those 72,000 BTUs per hour because it may only run 1/3 of an hour and give me heat.

Yes that is correct if in fact it runs for exactly 1/3 of an hour. My point was that the propane will run until it doesn't need to anymore whether that's for 10 minutes or 30 at a "rate" of 72,000 BTUs per hour. Meanwhile, the coal furnace has a variable heat output depending on how much attention you give it that averages 18,000 BTU's per hour.

It's like filling a tank with water that is constantly leaking while tweaking the faucet to and fro. Sometimes the level will rise, sometimes it will fall, if you get it right it stays the same. The heat in your house is doing quite the same thing.

Increasing the circulation rate will help even out warm and cool spots in your house.

And another thing that puzzles me (of many).
Why does my furnace perform so differently than others of the same make.

For example, Ky Speedracer takes the plug out of the back of his furnace to add more combustible air (I think that's why).
Removing the back of mine makes no difference.
I understand he has a draft that would suck a Buick through it if that has anything to do with it.

Same with over fire air.
It's supposed to burn off the volatiles.
Open or closed makes no difference.
In either case, the fire will sit and smolder and not make enough heat to run the blower until I poke holes in it to get some air.
Then it burns like crazy for the rest of that cycle.

I'm sure I could think of other idiosyncracies that defy the advice and suggestions from others.
I try really hard to precisely follow tips and suggestions.

To my simple mind, these aren't related to the quality of the coal or how much heat, but whether the furnace functions as it's supposed to but the mechanics of the furnace

Everybody here has been great with their patience and generosity in teaching and advising.
Thank you.

It's just frustrating that as I near the second year with fiddling with this thing that it won't do the job when it gets really cold and for me to be able to rely on it as a sole source of heat.

Sorry for the rant.

larryfoster wrote:In either case, the fire will sit and smolder and not make enough heat to run the blower until I poke holes in it to get some air.

You shouldn't have to poke holes in your coal. If you do, you have a high coking coal (I think that's the term).

If you use coal that doesn't coke as much, it won't get sticky, won't block the draft, and likely will be higher in BTUs.

larryfoster wrote:To my simple mind, these aren't related to the quality of the coal or how much heat, but whether the furnace functions as it's supposed to but the mechanics of the furnace

All of the symptoms you've listed to me are screaming bad quality of coal and/or coal sizing and/or improper clearing of ash..

Just for the hell of it, run some good quality hard wood for a few days and prove to yourself that the appliance can do what it's intended to do with good fuel and without ash in the way, which is to keep you warm.