Morso 7110B Burning Issue

[derell]

We had this stove installed in January and used it very successfully for the second half of last winter. So far this year, I'm having a lot of trouble getting good burns. The problem seems to be insufficient intake air - when I start a fire with the door open a bit, it lights well and develops pretty quickly into a good strong fire. Then when I close the door, with the damper fully open, the fire immediately dies way down, the flames start to look wispy like they don't have enough air, and then the fire becomes a smolder with hardly any actual flames. It didn't behave this way last winter.

The very good draft with the door open seems to suggest that the chimney is not the issue - it really seems like there's just not enough air making its way into the stove when the door is closed. I keep picturing someone trying to drink a thick milkshake through a straw. Could the intake(s) be clogged? I don't actually know where the air intake(s) are on the stove. I do have a window cracked in the room for make up air, and I'm burning dry wood (16-18%, mix of hard and soft wood). I read something in a different thread about Morso welding intakes shut for US versions of their stoves to increase efficiency ratings. The person who posted that said they drilled them open with a Dremel and then the stove worked really well, but I believe that was a different model.

Any thoughts here on what might be going on or what I could try? Thanks!

 

[EbS-P]

How did you measure the moisture content of the wood?

 

[derell]

How did you measure the moisture content of the wood?

With a moisture meter from Amazon. I actually bought the meter so I could test the wood prior to posting this question, since I suspected that all of the replies would just be telling me to measure the wood if I didn't. To be fair, I didn't measure freshly split pieces, but I tested a few different pieces in different locations, ends and along the splits, under the bark, etc. I got a little bit of variation depending on how hard I pushed in the probes, but didn't really see any numbers over 20%. I can check more tonight. Do you think wet wood is the issue here?

 

[EbS-P]

With a moisture meter from Amazon. I actually bought the meter so I could test the wood prior to posting this question, since I suspected that all of the replies would just be telling me to measure the wood if I didn't. To be fair, I didn't measure freshly split pieces, but I tested a few different pieces in different locations, ends and along the splits, under the bark, etc. I got a little bit of variation depending on how hard I pushed in the probes, but didn't really see any numbers over 20%. I can check more tonight. Do you think wet wood is the issue here?

Test in the center of a fresh split face. Those probes aren’t very long. If it’s still less than 20% we will ask some more questions. Generally hardwood needs to sit stacked and covered for a minimum split and stacked 2 years.

 

[kborndale]

I think wet wood is your issue, testing wood without resplitting it first is useless. If you were getting 20% on the outside, your wood is probably 30%+ on the inside. To get a totally accurate reading, the piece should be at room temp for 24 hours before you resplit it. Did you recently buy this wood? Wood dealers all say that their wood is dry but it very rarely is.

 

[derell]

Thanks for the replies. I'll split and test a piece tonight. I'll use a piece that has been inside at room temp. I did just recently buy this wood, and it was advertised as fully seasoned and ready to burn, but I understand that doesn't really mean much. Last season I was burning wood that had been stacked for years.

If wet wood is the issue, I don't totally understand why the fire would burn really well, blazing hot, with the door open but then appear as if it's being suffocated immediately when the door closes. But I am new to this and trust the collective wisdom here. I'll test the wood again and report back.

 

[EatenByLimestone]

With the door open, you’re pulling much more air into the stove. It’s like using a leaf blower to get a bonfire fire going. When you close the door, the volume of air slows to a trickle.

It’s worth asking if the chimney was cleaned since last year ended also.

 

[derell]

Thanks for the feedback. I split an piece of wood last night and measured the fresh split. My problem is wet wood, as you wise folks all suspected immediately. I'll try to find some other wood to burn while I let this recently purchased wood dry out more.

I have not cleaned the chimney since last year ended, but it was installed brand new in January and we burned less than 1/2 cord of very dry, well seasoned wood, so I'd think it was still pretty clean.

 

[EatenByLimestone]

It’s worth checking the chimney to make sure. Any surprises that come about from a dirty chimney are not good surprises.

 

[EbS-P]

Thanks for the feedback. I split an piece of wood last night and measured the fresh split. My problem is wet wood, as you wise folks all suspected immediately. I'll try to find some other wood to burn while I let this recently purchased wood dry out more.

I have not cleaned the chimney since last year ended, but it was installed brand new in January and we burned less than 1/2 cord of very dry, well seasoned wood, so I'd think it was still pretty clean.

At this time of year it’s probably worth buying sawdust bricks/logs. I used 9 packs my first winter.

You could set up small solar kiln. Stack wood in a room/garage with dehumidifier. I did both. They were not worth the efforts. So my first suggestion is the best.

 

[kborndale]

Thanks for the feedback. I split an piece of wood last night and measured the fresh split. My problem is wet wood, as you wise folks all suspected immediately. I'll try to find some other wood to burn while I let this recently purchased wood dry out more.

I have not cleaned the chimney since last year ended, but it was installed brand new in January and we burned less than 1/2 cord of very dry, well seasoned wood, so I'd think it was still pretty clean.

Unfortunately you have to buy your wood a year before you are going to use it unless your getting kiln dried wood (which isn't always baked long enough anyway) and that's just expensive. Very rare to find a wood dealer with dry wood.

 

[derell]

Thanks again for the responses. I have a source for about 1/2 cord of very dry wood (seasoned 5+years in a covered shed) that will buy us some time, but it sounds like the wood I have now won't be ready to burn until next winter, so I was also thinking about looking into a pallet of biobricks as Ebs-P suggested. Is it definitely OK to burn those in this stove? I can't find anything from Morso saying it's OK or not.

 

[EbS-P]

Thanks again for the responses. I have a source for about 1/2 cord of very dry wood (seasoned 5+years in a covered shed) that will buy us some time, but it sounds like the wood I have now won't be ready to burn until next winter, so I was also thinking about looking into a pallet of biobricks as Ebs-P suggested. Is it definitely OK to burn those in this stove? I can't find anything from Morso saying it's OK or not.

Don’t load it clear full of bio bricks. Start with a bed of coals and add one or two and a split or two. See how it goes. I had no issues with adding 4 in my F400. They can be hard to start in their own. The rule generally is 100% sawdust pro fare fine. Fireplace logs are not (a lot of times they have binders or are wax and cardboard). There is an old thread here somewhere where a user stuffed the entire firebox full. Don’t start that way but if you find you have good air control keep adding a couple at a time I’d you feel comfortable.

 

[kborndale]

You may be able to mix some of your wet wood with some bio bricks or the dry wood you are getting to stretch it a bit. Construction lumber or pallets can help you burn your less than ideal wood too, just make sure it isn't pressure treated (will have a green tinge to it if it's pressure treated).

 

[derell]

Thanks! I know not to burn PT lumber or fireplace logs in my stove. I'll try to mix the dry wood I can get with some biobricks to get me through this winter. Appreciate all the help on this forum!

 

[EatenByLimestone]

Pallets are also a source for dry wood. They’re often free.

 

[begreen]

Clean the chimney frequently if burning mixed dry and wet wood. Once a month would be good until only dry firewood is burned.

 

[Brr]

Oddly, I have the opposite issue in our second year with the 7110b. Can't stop the air down enough. Our wood is drier this year. I wonder if the wood is the variable for both of us.

 

[begreen]

It will burn quite differently now that the wood is seasoned. Try closing down the air much sooner. Do this in steps. Burning larger splits of wood will also slow down the fire.

How tall is the flue system on the stove?

 

[Brr]

Thanks for your help. The flue is 18 feet.
Once the fire is first going, I've been closing the air supply all the way down. I don't even need to open the air control when reloading wood. The fire is too aggressive. The fire doesn't appear as sensitive to changes in the air control this year. Stove top temp right around 500F which is borderline over-firing. I don't have a flue thermometer. I'm planning to check the ash tray to make sure there's no air leak coming from there. Im not too worried about it, but I'd like to stop down the air a bit for longer burn times. If you have any other suggestions I'd welcome them!

 

[begreen]

18 ft is a good height. The stovetop temp on this stove can go to 750º and not be overfiring. 500º is cruising temp. Try turning downing down the air sooner, well before the fire builds up to full strength. Do this in increments.