No overnight burns??

[Northern Flame]

Hello Hearth Guild!

I recently saw, in a Morso7110 owners manual, that I should not burn the stove overnight. Since that is a main way many (if not all??) wood stove users keep their stoves home warm overnight, I'm curious why this was written in the manual? Just for safety, and to make sure THEY as a stove company recommend you don't run your stove when your not around it?

Can someone explain this to me? Has anyone seen this in other manuals or from other companies?

Thanks and Take Care!

 

[peakbagger]

A very innocent but controversial question. No right or wrong but what the heck I will dive into it.

As you noted many people do overnight burns safely, they also may have far different stoves and chimneys. The stove if properly installed will not burn the house down due to an overnight burn. It could in rare situations due to negative pressure in the home be a Carbon Monoxide (CO) hazard if the draft is marginal or some sort of negative draft is turned on when the stove is out. When the stove is on the last stage of a burn, the draft up the stack is weaker than when it was running. If you were to have a automatic fan of some sort turn on when the stove was not running, possibly a furnace or bathroom exhaust fan, you could pull a backdraft down the chimney into the stove and out into the room which would be rich in CO. In theory you have at least one preferably more CO detectors in the house and they will rapidly let you know if there is CO in the house. Some folks have had this issue and it take some sleuthing to figure out but it usually comes down to poor draft and a air tight house.

Efficiency and air emission wise, its best to burn the stove hard and adjust its output by feeding it wood. Your stove does not have a catalytic combustor and uses airwash and secondary air for combustion and that is less capable of turn down. Thus the manufacturer is encouraging you to have a fast hard burn and then let it go out at night. The typical approach to trying to get an all night burn with a stove not designed for it is to get a good hot fire and then load it up with wood, then turn the air controls down low to starve the stove of air, that cuts the flame temp way down and you now have a creosote creator. The EPA and the manufacturers know that trick so some stoves have two sets of air ports, one set you can control and the other set is hidden so if you try to crank down the stove with lots of wood in it the hidden air ports kick in and the stove keeps burning at reasonable temps until it runs out of wood. Some folks find these ports and plug them and turn the stove into a "smoke dragon" and creosote creator. Consistent operation like that will increase the pollution out the stack and build up more creosote in the chimney.

That is my opinion and I am sticking with it I used to tune up biomass power plant boilers for a living so I hope I know what I am talking about but expect a few other folks have decidedly different opinions.

 

[Northern Flame]

Interesting. very informative...and thank you!!

So...I didn't buy the Morso yet. I did order it and it's coming from Denmark. But I am trying to figure out if I should buy that or the other one I was looking at, the Hearthstone Castleton. That brand seems to be more open to running your stove overnight. I checked that manual and there were no warnings about burning overnight. So, I take that as a thumbs up.
I am also limited by the space I have, for now. It will be a hearth mount with a flexpipe wrapped in insulation that runs up the masonry chimney. most of the stove will sit outside of the heart but a few inches will still be in there. Eventually when we remove our carpet I will get a pad and move the stove out a bit more, etc. But for now that is what i am working with. But I definitely want something that I can fill before going to bed and come down, stoke some coals, through logs on get start it back up.
Would you say that the Morso is not the stove for that job? I leaned more that way because it fit well in the heart, was not as deep as the Castleton, and gave me a bit more room, and frankly was about a grand cheaper. But, now, i don't know......

 

[gthomas785]

With a new stove / install / operator I would recommend initially sticking around to observe the stove for several full burns so you get an idea of what it is doing. If you find that it can go for several hours without needing to be poked, adjusted, or brought under control, then it should be fine to leave it when you go to bed. According to the owners manual, you'd be doing that at your own risk.

I do not recommend plugging air holes. Just turn it down to the factory level that you desire. If you want more turndown than it can give you, get a catalytic stove.

 

[kennyp2339]

Make sure you read hearth requirements on what ever stove you choose, some stoves require just ember protection, others require a hearth with a K factor rating that includes 18" in front of the loading door.

 

[aansorge]

Longer burn small stoves:

Palladian Soapstone Wood Stove

SIMPLICITY, BEAUTY, CRAFTSMANSHIP Like all Woodstock Soapstone Wood Stoves, the Palladian has earned an unmatched reputation for quality, longevity and heating comfort. It will store heat when the fire is hottest, and thanks to the magic of soapstone, it will continue to radiate that heat l

woodstove.com

https://www.blazeking.com/wp-content/uploads/2020/08/BK_CSA_20-2_Broch_2020.pdf

The blaze kings have good clearance to combustible ratings (they can be closer to walls than many other stoves).

Both of these stoves are cat stoves and burn much longer than the 1 cu ft Morsoe.

 

[Northern Flame]

Make sure you read hearth requirements on what ever stove you choose, some stoves require just ember protection, others require a hearth with a K factor rating that includes 18" in front of the loading door.

You're referring to the clearances? It's tight with both stoves. I was going to lay something down in front of it to aid in that.

 

[Northern Flame]

With a new stove / install / operator I would recommend initially sticking around to observe the stove for several full burns so you get an idea of what it is doing. If you find that it can go for several hours without needing to be poked, adjusted, or brought under control, then it should be fine to leave it when you go to bed. According to the owners manual, you'd be doing that at your own risk.

I do not recommend plugging air holes. Just turn it down to the factory level that you desire. If you want more turndown than it can give you, get a catalytic stove.

yeah, i hear ya. i wasn't go hog wild at first. But I do want that as an option, so I want to make sure I'm buying the right thing. It's weird, because my brother in law has a Jotul F100. Smaller than the Morso and he will load that full at night and then come back to embers. Even with that little stove. Crazy....

 

[gthomas785]

yeah, i hear ya. i wasn't go hog wild at first. But I do want that as an option, so I want to make sure I'm buying the right thing. It's weird, because my brother in law has a Jotul F100. Smaller than the Morso and he will load that full at night and then come back to embers. Even with that little stove. Crazy....

I should mention that the "maximum burn time" depends just as much on your chimney as it does on the stove. Too much draft will mean you can never turn it all the way down and it will chew through wood faster, no matter the stove.

 

[SpaceBus]

My Morso 2b Classic manual says the same thing. I like to light a small, fast, hot fire in the evening so I have a nice bed of coals when it is bed time. Then I load it full and wait a few minutes until the air is closed down to "cruise" setting and I go to bed. The stove is already hot and easy to get back to a steady burn when loading on active coals. The chimney drafts well and I only have momentary draft reversals when trying to light the stove in a storm. Once the fire is established I have never had puffs or draft reversals, same with my other stove. If I use hardwoods or larger softwood splits I can have coals buried in the ash to relight the stove in the morning, if needed. The 7110 is not that much larger than our 2b classic and rated for about the same size home. Seems the stern warning for overnight burns is a liability statement more than anything else.

 

[Northern Flame]

My Morso 2b Classic manual says the same thing. I like to light a small, fast, hot fire in the evening so I have a nice bed of coals when it is bed time. Then I load it full and wait a few minutes until the air is closed down to "cruise" setting and I go to bed. The stove is already hot and easy to get back to a steady burn when loading on active coals. The chimney drafts well and I only have momentary draft reversals when trying to light the stove in a storm. Once the fire is established I have never had puffs or draft reversals, same with my other stove. If I use hardwoods or larger softwood splits I can have coals buried in the ash to relight the stove in the morning, if needed. The 7110 is not that much larger than our 2b classic and rated for about the same size home. Seems the stern warning for overnight burns is a liability statement more than anything else.

Good Advice. Have you had any creosote issues doing that?

 

[peakbagger]

My guess is the key thing is he is not doing is cranking the air way down to stretch the burn. Once the stove is cruising its not going to suddenly overheat or go out if the air is left open. So going to bed with a full load that is cruising and letting it burn out will not typically build creosote. BTW creosote forms while the log is boiling out volatiles and moisture once they look like burning coals in the later burn states creosote does nor form.