Never Burned Coal Before...Advice?

Hello all,

Just lit my first coal fire yesterday afternoon and have some quick questions for the experts . I also have a thread over on the Stoker forum, but wasn't sure if maybe here was a better place to be for what I have. Wife and I bought our home in 2002. Has oil fired warm air heat, but also had a coal furnace already tied into the ductwork. Like the oil heat, but the cost of fuel oil is killing us . That in mind, figures it's time to try the coal furnace. Kogen unit, built in PA. Not sure of it's vintage, seems to be well built though . Have only a manual damper in the flue (no baro), as well as the bottom draft and a draft control in the loading door. Here are a few quick pics:

Front:





Rear:



Flue:



Here's where I'm at. Started the fire around 3 PM yesterday, using charcoal and 2X4 scraps. Had her burning good and hot on only the second attempt, but left the ash door and flue damper open until well established (as suggested by some). Once burning, I closed the bottom damper approximately 1/2 way and left the flue damper open fully. Around 6 PM, the stack temperature was up over 600F, so I closed the bottom damper and flue damper fully to bring the temp down (kinda panicked I guess ). Before bed (around 1 AM), the house temperature was over 80F, so I opened the flue damper fully. Not sure if this was the right move, as I am very new at this. Can't reduce the draft anymore though to bring the temp down, thought this may let more heat escape...

Stack temperature now ranges from 250-450F, depending on how recently coal was added. House started this morning @ 72F (when I shook and refilled), but was again up to nearly 80F when I left for the day. Down to 77F now, but still a bit warm for us (we're used to 68F with the oil furnace). I don't mind a little warmer, because I know coal tends to be warm. 72F feels good, but I cannot keep it there...

Not sure what to do. Some have suggested opening the loading door draft to pull some draft from above the fire. Some have suggested turning off the convection blower and letting the heat radiate. Thoughts?

Thanks,

Joe

Joe,
First thing I would do is close the ash door damper to just a crack, close the MPD and open the load door damper just a hair this should bring down the stack temp.
It will take a little while for the fire to settle down.
After you load your next batch of coal leave the MPD fully open for bought 10 or 15 minutes til you get a little bit of blue flames and close the MPD fully then use the damper on the ash door to regulate the fire , more air= hotter fire, a "little" over the fire air from the load door is OK as it will help keep the gases burned off from the fresh load of coal.
You will have to play with the settings till you get your stove dialed into to what works best for you.
Just remeber that closing the MPD and closing the air on the ash door will cool your fire down, and opening it up lets her get HOT

Joe,

I saw that you started another thread in the hand fired forum. That probably is where this whole discussion should be. Perhaps a mod will move everything there as it appears that you do indeed have a hand fired furnace. And the mods do not like multiple threads. But I do realize that you want some answers NOW.

That said. A couple of things I might offer. First off, a baro damper will help out. What they do is to help regulate the draft on the entire burning process. If you have a good draft (only verified by a manometer), a baro will allow you to keep that same measured draft. As the stove increases in heat output, the draft would increase due to higher stack temps. If that would happen,the baro would then open to allow room air to be pulled into the chimney instead of pulling air through the burning coal, thereby making more heat. Most manual pipe dampers do still have some open areas in the center to allow air to pass even when fully closed. Look into getting a baro !!!!!!

IF the draft doors on the furnace do NOT seal properly, you cannot control the draft with the sliding covers. You see, without the seals being there, air is still entering when you don't want it to. If the seals are working properly, you could actually choke out the fire just by using the draft controls. Opening the loading door slots may indeed allow over the fire air which would lower the draft from the bottom door. However too much over the fire air may also help to put out the fire due to not enough air coming up through the coal.

Right now we are experiencing unusually high temps for this time of the year. Until this front passes through and the temps drop, most here resort to the use of "window stats" or the opening of the house windows. It's just the way it is. You cannot just shut off the coal burning process on a hand fired appliance without shutting it down completely, waiting for the temps to drop and then restart it. It appears that you have a well made furnace. Once that coal heats it up, it will take some time for it to cool down. Likeways it does take some time for it to heat up. That is the nature of coal burning. It is slow to respond either way. But it can maintain temps quite well. This is part of the learning curve.

In due time you will learn how to become your own weatherman. You will adjust YOUR stove based on anticipated outdoor temps. Now stoker stoves and stoker boilers do this with the use of thermostats but they will still have temp overshoots.

Hang in there, shed some clothes, have a cold one and enjoy it. These high outdoor temps will not last too long.

Rick

Joe, you have already crossed the first bridge...you figured out how to start a coal fire and get a long burn! That furnace has a monster firebox, I bet it can really throw some heat.

From your description it sounds like the furnace is getting combustion air from someplace other than the inlet damper...like around the ash pan door. Check the gaskets and see if air is leaking by. Opening the load door damper a little will also help, and it will help burn off the gas from fresh load of coal. Once your fresh coal is burning I would run the flue pipe damper in the closed position.

It has been pretty warm the last couple days, you may find that even with all the dampers closed tight this furnace puts out more heat than the house needs on mild days.

Perhaps a mod will move everything there as it appears that you do indeed have a hand fired furnace.

Your wish is my command!!

Short Bus wrote:Sounds like an air leak,

Check gaskets on doors.
Grate shaker handle hole looks like a big leak.

A cigarette or candle will tell you easy enough. Just run it along the door's edge and watch the smoke or flame, it will tell you if and where it leaks.

I'd probably replace the ash pan door gasket. A baro is a good idea as it makes your draft more predictable. My thought is are that since the stove was made and installed, and the condition of the house now, energy saving improvements have made such a large stove unnecessary and it is oversized for the house. You can slow a fire down by tossing the next lower size coal in it to lower the heat output. Since your burning nut, get some pea sized coal and put a layer of that on it will cool it down, and slow the burn. Also throwing ashes on a fire is a good way to cool and slow it down, or if it gets somewhat out of control and you don't want to use water. I keep them handy too.

Sounds to me like the stove works great and you have excellent draft. You may try running it completely closed (including the damper) and then see how it does, opening the bottom air just a crack as it gets colder outside. Stuffing it full of coal and limiting the air will slow the burn.

Hello again,

Thanks so much for all of the great advice. I do feel a little more comfortable now .

Left the fire go out Saturday night and plan to do some minor maintenance before lighting her up again. Plan to replace both door seals and possibly install a baro. May even replace all flue piping, depending on cost. If I do, is it recommended to leave the MPD in place, or run with just the baro? I read through the MPD thread, but there was a lot of mixed opinion there. Thoughts?

I know stack temperatures were around 400F once a new load was burning well (several hours). Would like to get down around 200-250 and stay there. Sound good?

I've also never had this thing FULL. Filled it to roughly the bottom of the loading door, not nearly to the top of the firebrick. Should I be filling it completely full? Also not sure on how long to shake. Seems most say to stop when hot embers start to fall through. Is this correct?

Thanks for bearing with me guys ,

Joe

Top of the bricks...
Keep the MPD...
Stove, MPD, Baro, Chimney...

Joe,
I personally like both ..the Baro & MPD as a team ...they really can work together I.M.O.

Tim wrote:Joe,
I personally like both ..the Baro & MPD as a team ...they really can work together I.M.O.

Ditto

dj

Hello everyone,

Thanks again for the advice, just wanted to update. Installed new door seals and a baro yesterday. Will fine-tune it with a manometer (could not get one until tonight), but set it to .06 per the weight. Should be close I guess...

Added the final scoop to her around 8:15 last night. Draft is closed about half and the MPD is fully open. Stack temp has satyed between 325 and 375 all night. House has remained between 72 and 74, which is PERFECT. Much better than with the leaking door seals and missing baro.

Only other question is this. Could this be refined any more, or does this sound okay? Not sure if and when I should be closing the MPD. Thoughts?

Thanks,

Joe

Close that MPD after loading your stove. It will chug along with stack temps at or below 200°F while keeping the heat rolling off of your stove into your house.

cabinover wrote:Close that MPD after loading your stove. It will chug along with stack temps at or below 200°F while keeping the heat rolling off of your stove into your house.

Thanks . Have had her running since about 10 AM (noon here now) with the MPD closed and the stack temp is actually still @ 350F. This is even with the draft slightly more closed than last night (now only opne 1/4 or so). Seems almost like it's running hotter with the MPD closed . Thoughts?

Thanks, sorry to sound dumb ...

Joe