Hearthstone Mansfield 8013 - 24/7 burning during cold temperatures

[5U4]

Notes:
Heating space - 2,200 sf well insulated
Stove - Mansfield 8013
Wood species - Red Oak, Beech, Black Birch
Wood seasoned - 4 year
Wood moisture - <= 16 percent
Wood length - 18"
Split diameter - 4-6"
Burn Cycle - 8:00pm, full fuel load; 9:00pm, stove at operating temperature and air control at low burn position; 12:00am, air control full open; 6:00am, significant quantity of coals preventing full fuel reload.

When outdoor temperatures are in single digits, and continuous burn cycles, there is an excessive amount of coal buildup causing delays in loading fuel while waiting for the coals to burn down, in turn low heat output and falling room temperature. The coal buildup is a problem, as it prevents continuous heat output and the ability to maintain a minimum room temperature of 65F during cold nights.

In general, it appears the Mansfield does not burn to a fine ash, especially toward the back of the firebox where after an all-night burn there is significant size slow burning coal chunks.

Is this coal issue unique to the Mansfield? Any proven "safe" methods/operating procedures to combat this issue?

 

[wetwood4life]

Smaller splits should burn faster and leave smaller/fewer coals.

You could also run a short cycle to burn down the coals. Like 1/3 load of small splits. It'll put out good heat, and a couple hours later you can do a full load on fewer coals.

I have the Castleton, which I believe is the Mansfield's little brother. Similarly square firebox, anyway. The back split never burns down all the way. It often won't even coal. Design flaw of the stove, in my opinion. Air comes in the front (and top tubes) and exhausts out the top front. I think the back has dead air due to the deep firebox. I just consider it a high-touch stove, and make sure to stir/rotate the coals regularly for an hour or two before reloading.

 

[Highbeam]

Burning half the time on the lowest air setting and then half on high seems weird. Is there not a medium? You need to be burning up wood faster.

Wood heat comes in cycles so you’ll need to overheat the home during the first half of the load so that during the cooler coaling stage the house temp might fall enough for another spurt of heat.

My last stove was a hearthstone heritage.

 

[5U4]

Yes, weird! Unfortunately there is no temperature controlled feedback loop to do the task, wonder why?

Venting system has high draft and at low setting stove runs at just below the max allowable temperature. When the temperature starts to fall change to high setting in attempt to burn off coals, the rock temp doesn't increase at this point - you know thermal lag, what you see for temp on the rock is out of sync with the heat source.

The small split concept does help, it may work better with soft wood which I don't have at this time and will have to explore further.

Any other tricks to combat excessive coal buildup?

 

[all night moe]

A burn consisting of pine will give a good quick heat output and, use up some existing coals.
Just make sure the pine is seasoned as well. A year or more.
You can also use dry bark to burn up some coals.

 

[wetwood4life]

The small split concept does help, it may work better with soft wood

Hard wood should work just as well! It has relatively more surface area than thick splits, so the whole piece of wood gets up to temp and burns down faster.

 

[stoveliker]

If I have more coals than I want, I rake them to the place where the air flow is strongest (in my stove the front in an East-West long hill). Don't flatten the row of coals; best if it's a bit uneven

Then I put a split of fast burning wood on top. For me best if it's pine. I dislike maple for this as it'll give more ashes covering the coals preventing them from burning up.

This split burns and keeps the air from going over the coals+split. Instead I see it rush thru the channels underneath the split ormed by the uneven coal surface and the split above. This leads to white hot pockets (blast furnaces) where coals quickly burn down. And it gives good heat (for a short time).

 

[Pinesmoke]

Red oak and beech beech do the same thing in mine. Making charcoal seems to be "normal" for theses stove. When I'm burning hard I rake the coals up into a pile and burn pine on top of them first load of the day to burn them down.

Also when I'm around to tend the fire smaller loads running hot to gradually burn the charcoal down as the day goes by works well.

 

[Todd]

Are you raking the coals and unbury wood to the front before reloading? That always helped me with a deep firebox.

 

[Pinesmoke]

Are you raking the coals and unbury wood to the front before reloading? That always helped me with a deep firebox.

Depends on the reload I'm doing. A hot reload I'll take them out flat across the entire box and cover them with wood. They seem to burn straight down pretty evenly. A reload after 8-10 hours is more charcoal than embers, they aren't all that hot. I rake them to the middle and out of the back and pile the pine on top, about 3 splits. Leave the door cracked and it's rockin in 10 minutes. Close the door and leave full air. By the time the second small loads done the cats are up and running hard and the stove hot. Load and go from there.

With the stove like that I can do about anything air wise and keep the cats hot easily no matter the size of the load. I don't habitually run a full load each time, smaller loads when it's not as cold and it's easy to stay up high on the cats