Help using 1972 Nashua N18 - not getting the heat I expect

[reforminded]

Howdy--been reading this excellent forum for months and just registered seeking some advice. My wife and I bought a 1972, 1570 sq/ft contemporary house in April, and it has a Nashua N18 wood stove in the basement. We believe it was original from when the house was built--and had it inspected and cleaned prior to use. I have 2 cords of wood that seasoned for 2 years, purchased from a local woodsman in his late 70's who has been supplying firewood to those lucky enough to be on his list since he got back from Vietnam. I got onto his list because my Mother has been buying her wood from him since the late 70's. He loads and inspects each piece by hand, and my friends who helped stack it said it was the best wood they had seen. It is a mix of red oak, ash, birch, and maple.

The problem I am having is getting good heat from the stove, and I have tried to follow all the advice I have read here. I start a fire with the front vents wide open, get it up to about 350 on the flue gauge, then choke them down to about 1 turn open. 30 minutes later the temp will have dropped to 220-250ish, so I open them wide again and it gets going, but it is just eating wood. The house never gets very warm (mid to high 60's in the rooms right above it) and if I choke it down for longer burns the temp just goes right back down. It also has a butterfly switch in the flue, which I leave open while burning. It has a blower and vents tied into 1 duct going into the living room, and one going to a finished room in the basement, under the bedrooms. Running the blower or not doesn't seem to make that much difference in heat distribution. In the pic below of my current burn, I have had it wide open for about 30 minutes trying to get the temp back up. When I look at the chimney I do not see smoke, so I think that means I am getting clean burns, but given what I have read about people with similar style stoves overheating the house, and given how much wood I am going through (this thing literally just devours wood), I do not think the current amount I have will last through January--the coldest time of year. The house is all electric baseboard, which I am trying not to turn on and when we first moved in and had to use them lightly I nearly fainted as the first bill.

I grew up in a house with a 1978 Vermont Castings Defiant in the living room, and I could get that thing cranking to the point where we had to open windows. It would burn all night and the house would be a 75 degrees. I feel like I must be doing something wrong with this Nashua, as other people rave about these stoves. I do a final load at midnight, get it roaring, then choke it down and by morning (7am) the stove is barely warm to the touch and there are almost no coals left. Any advice is greatly appreciated!

 

[fbelec]

hi welcome to the forum
take the bottom thermometer and put it on top of the stove in the middle toward the smoke pipe. and tell us what reading you are getting in the middle of the burn. then try turning your smoke pipe damper 3/4 closed and see what that does. each time you burn try closing the smoke pipe damper more and more closed for optimum temp and no smoke coming from the stove. that will be your sweet spot for that damper.

frank

 

[reforminded]

hi welcome to the forum
take the bottom thermometer and put it on top of the stove in the middle toward the smoke pipe. and tell us what reading you are getting in the middle of the burn. then try turning your smoke pipe damper 3/4 closed and see what that does. each time you burn try closing the smoke pipe damper more and more closed for optimum temp and no smoke coming from the stove. that will be your sweet spot for that damper.

frank

Thanks, frank! I have a pretty good fire going for the last 40 minutes, stove top temp showing roughly 525 F, flue temp 30” up showing 380 F, and I haven’t choked down the flue yet.

 

[reforminded]

Wow! So after that post I closed the flue damper to 3/4 closed, and I Just checked roughly a half hour later. Flue temp at about 380, stove top temp up to 600! The load of wood is all burning but still has a long long way to go. I closed the air vents to just barely open and have the flue damper 3/4 closed. Eager to check it in another half hour.

 

[reforminded]

Wow! So after that post I closed the flue damper to 3/4 closed, and I Just checked roughly a half hour later. Flue temp at about 380, stove top temp up to 600! The load of wood is all burning but still has a long long way to go. I closed the air vents to just barely open and have the flue damper 3/4 closed. Eager to check it in another half hour.

Okay so that didn't work. With the front air vents choked down (but still open a little) and the flue damper at 3/4 closed the fire started to smolder. Flue temp dropped to 220ish F and stove temp dropped to just under 400 F. Opened the vents back up a full turn and opened the flue until it was burning again, then closed the flue back down to 3/4 but leaving the vents open a full turn. Will report back.

 

[reforminded]

w

Okay so that didn't work. With the front air vents choked down (but still open a little) and the flue damper at 3/4 closed the fire started to smolder. Flue temp dropped to 220ish F and stove temp dropped to just under 400 F. Opened the vents back up a full turn and opened the flue until it was burning again, then closed the flue back down to 3/4 but leaving the vents open a full turn. Will report back.

ell--added a couple logs at the last post and within 15 minutes the stovetop was up to 650ish and the flue at 460ish. Very hot! Left the flue damper 3/4 closed and closed the vents a half turn to try to bring it back down a little. I don't think I am understanding the relationship between the air vents and the flue damper. I thought that by closing down the flue damper it would cause the fire to choke down because the draft through it wouldn't be as strong?

 

[brenndatomu]

damper 3/4 closed

Might need to go more than 3/4...even at "100%" closed, it still doesn't block the flue totally...

 

[fbelec]

yes that is why i was saying close down the damper a little each time you load it with the air in the same spot so that you can find the sweet spot. depending on how big your draft is is what the pipe damper is working. it will keep the heat in the stove instead of going up the pipe. it takes time to learn. a lot of people can shut the pipe damper all the way, years ago when i had one i couldn't. but keep closing it and go 30 to 60 minutes between each time you touch it until you find your spot

 

[reforminded]

yes that is why i was saying close down the damper a little each time you load it with the air in the same spot so that you can find the sweet spot. depending on how big your draft is is what the pipe damper is working. it will keep the heat in the stove instead of going up the pipe. it takes time to learn. a lot of people can shut the pipe damper all the way, years ago when i had one i couldn't. but keep closing it and go 30 to 60 minutes between each time you touch it until you find your spot

Woke up today to a stovtop still at 200 degrees, and after stirring the coals was able to put a couple logs on and crack the door and get a good fire going again. Definitly the longest I have had a load of wood last so far. Where should I have the air intakes set before I start closing down the flue damper to find the sweet spot? Do I leave them wide open and do all the control with the flue damper or is it better to shut them down like halfway?

 

[brenndatomu]

I always adjust the pipe damper last...but I've never run one of these stoves though either...although it doesn't sound that much different that other stoves...

 

[bholler]

Woke up today to a stovtop still at 200 degrees, and after stirring the coals was able to put a couple logs on and crack the door and get a good fire going again. Definitly the longest I have had a load of wood last so far. Where should I have the air intakes set before I start closing down the flue damper to find the sweet spot? Do I leave them wide open and do all the control with the flue damper or is it better to shut them down like halfway?

There is no set answer for any of this. Every stove will react differently to every chimney. You are just going to have to figure out what works best for your setup.