# Nashua wood stove tied into duct work, how to use?



## Ejraste (Oct 5, 2019)

I recently purchased a home that has a nashua wood stove tied into ductwork.  My home is all electric so it has a heat pump.  I am new to this,  so pretty unsure on how this works but can anyone point me in the right direction on how to use the wood stove that's attached to the ductwork?  I will attach a picture of my setup.


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## SpaceBus (Oct 5, 2019)

What does the left hand side of the pipe connected to the right side of the stove do?


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## Ejraste (Oct 5, 2019)

SpaceBus said:


> What does the left hand side of the pipe connected to the right side of the stove do?


Sorry it's not shown in picture but that connects to left side of the wood stove the same way.   It has a blower fan on back of wood stove.  Do I just run the blower and start burning some logs?


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## TWoods (Oct 5, 2019)

Ejraste said:


> Sorry it's not shown in picture but that connects to left side of the wood stove the same way.   It has a blower fan on back of wood stove.  Do I just run the blower and start burning some logs?


I grew up with one of these.  Great stove!    And yes, the blower in the back circulates air around the firebox and then pumps it out the sides.   There should be 2 ports (one for each side).     If you are connected up to the furnace duct work, then you should be good I think.   Nice set up for sure.

If you are new to wood burning, always make sure the exhaust port, stove pipe and chimney are clean before your light it up.      And inspect the firebox too....should have splits (firebricks) and be clean .

Enjoy the stove.


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## Ejraste (Oct 5, 2019)

Awesome thanks!  The house was built in 88 and we purchased from original owner.  I don't think they ever used the wood stove.  Do I need to run the fan on my heat pump to push air through duct work?  I'd def like to use the wood stove this winter to alleviate some of the pain of a high electric bill.  Also,  what's the best plan to get the longest burn going while im at work, as I don't want my wife to have to worry about it.  Thanks again!


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## SpaceBus (Oct 5, 2019)

It's not the most efficient thing in the world but yes, light it and start the blower. Set your heat pump thermostat to come on at whatever temp is the lowest that your wife will tolerate and load the stove according to how much you wish to spend on electricity. Without seasoned firewood this will be very frustrating. Once you get the hang of this thing I suggest looking into a Kuuma Vaporfire


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## SpaceBus (Oct 5, 2019)

I'm not familiar with your specific stove, but they all operate mostly the same. Yours looks like a Fisher style stove so I would ask @coaly for his advice as he's the local expert on these older style stoves.


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## Ejraste (Oct 5, 2019)

Ok thanks for the input.  It's a nashua n24 I believe.  I m pretty sure I need to line inside with the fire bricks as there aren't any.  Even if it gives me a little extra heat and saves on electric bill I'll be happy.


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## coaly (Oct 5, 2019)

When starting it, bring the firebox up to temperature before turning on blowers. You want the firebox hot for a cleaner burning fire. You can extract so much heat you will create creosote in he chimney.
Put a magnetic surface thermometer on the stove pipe at elbow. You have no clue what you're doing without it.
The object is to keep flue gas temperature ABOVE 250* f. all the way to the top of chimney _*while smoke is present.*_

Water vapor is a byproduct of combustion and rises out the chimney flue with smoke particles. Below 250* it will condense on chimney flue walls allowing smoke particles to stick. This is creosote. The surface thermometer will read approximately 1/2 the actual inside flue gas temperature. It is a guess how much cooling you will have due to indoor or exterior chimney, insulated liner to keep much hotter, height and very importantly diameter of chimney flue. If this has a square 8 X 8 liner, and a smaller 6 inch outlet and connector pipe, you have an extreme amount of cooling as gasses expand in the larger chimney. This is the reason for the need of the correct size insulated liner. The chimney flue must be the same size as your stove outlet pipe to extract so much heat. The stove simply won't be able to let so much heat required up the chimney to have enough to heat the building from its excess heat. The system will work fine, but it's all about the chimney.

The chimney is not there just to let smoke out. Rising gasses inside the flue are lighter than air and this differential temperature makes a differential pressure inside the chimney, pipe and stove firebox. This lower pressure is the cause of DRAFT. The lower pressure in the stove is what allows the higher atmospheric pressure to PUSH into the stove feeding oxygen to the fire. You can see how the chimney is what makes the stove work and is considered the engine that drives the stove.

In your case it becomes more important since you can't have any waste going up the chimney to extract the right amount of heat. It's a fine line between chilling the firebox and burning clean. Since it hasn't been fired in quite some time, burn a few small fires to dry the firebrick. Brick inside the firebox absorbs moisture from the atmosphere and the first fire uses a lot of BTU to drive this moisture in the form of steam up the chimney. Heat output will be noticeably low with new, or brick containing moisture for the first fire.

Normally stoves _*radiate*_ heat in all directions. Yours also uses _*convection* _to heat the air.
Also the AIR INTAKE for the blower system becomes very important. It needs to get air from the heated area the ductwork supplies. (the stove heats recirculated air from the heated area of the structure) So there should be a return air duct coming into the stove to be recirculated by blower and ducting. If it is simply open to the basement, a door or stairway leading up to the heated area must be opened to allow circulation. The vacuum created by the air handler can put the basement into a low pressure area overpowering the chimney draft, causing a reversal of chimney, since blowers are much stronger than chimney draft. (smoke will pour out the intake vents)Remember, combustion in the firebox relies on atmospheric pressure to make it work, that comes from any air intakes of cracks into the basement. So make sure the stove gets fresh air if the return is not ducted properly.

Have you ever built a fire in any stove before? I can give you the basics of where to set the air intakes and how to start a smokeless fire if you need it.


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## TWoods (Oct 5, 2019)

When you go get new firebricks, my advice is to get a mid range one....the really cheap ones tend to crack after one season.  The expensive ones are well .....expensive.   I forget the cheap brand from home Depot  I tried a few years ago, but I have had good luck with those made by Rutland.....but I am sure there are others.

One more thing, those blower fan motors  do fail eventually..they normally get louder and louder as the bearings inside wear out .   I wouldn't worry about it too much since your unit is in the basement and you probably don't care about the noise but it is just something to keep in mind.    Shouldn't be expensive or hard to fix when it does go.   I' d just look online when the time comes.   Most electrical supply shops would be a resource too.

Again, enjoy the stove.    Nice rugged unit.


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## Ejraste (Oct 5, 2019)

TWoods said:


> When you go get new firebricks, my advice is to get a mid range one....the really cheap ones tend to crack after one season.  The expensive ones are well .....expensive.   I forget the cheap brand from home Depot  I tried a few years ago, but I have had good luck with those made by Rutland.....but I am sure there are others.
> 
> One more thing, those blower fan motors  do fail eventually..they normally get louder and louder as the bearings inside wear out .   I wouldn't worry about it too much since your unit is in the basement and you probably don't care about the noise but it is just something to keep in mind.    Shouldn't be expensive or hard to fix when it does go.   I' d just look online when the time comes.   Most electrical supply shops would be a resource too.
> 
> Again, enjoy the stove.    Nice rugged unit.


Thanks.  Also,  There is a new blower in a box waiting for me next to the stove.  The blower that's on there right now is insulated and taped to the stove?? Is that supposed to be that way? The way the house was kept and designed,  I would think he had the stove setup correctly.  All the piping is new and clean and in good condition.  I was just worried about the safety side of using it with children in the home.


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## Ejraste (Oct 5, 2019)

coaly said:


> When starting it, bring the firebox up to temperature before turning on blowers. You want the firebox hot for a cleaner burning fire. You can extract so much heat you will create creosote in he chimney.
> Put a magnetic surface thermometer on the stove pipe at elbow. You have no clue what you're doing without it.
> The object is to keep flue gas temperature ABOVE 250* f. all the way to the top of chimney _*while smoke is present.*_
> 
> ...


Thank you for all of that information. I'm hoping the owner had everything setup correctly as far as piping and tieing it into the ductwork. Hopefully all I have to do is buy some bricks and get some fires going the way you said.    And no,  I haven't really had the experience of starting fires in a stove before.


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## TWoods (Oct 5, 2019)

I don't know about the blower covering.   I suspect it's fine and you can always try it (I think the fan only comes on when the stove reaches temperature but maybe there is an on switch too?). Good you have a spare.

Coaly gave you good advice on firing up.    It seems obvious, but also make sure you have all your smoke detectors in working order with new batters....carbon monoxide ones too.   Never can be too careful and depending on where you live, the local zoning may or may not have required things to work as part of the house sale.

Again, good luck.   Had one in the house I grew up in.   Good stove.  You'll like it.

Cheers,


Ejraste said:


> Thanks.  Also,  There is a new blower in a box waiting for me next to the stove.  The blower that's on there right now is insulated and taped to the stove?? Is that supposed to be that way? The way the house was kept and designed,  I would think he had the stove setup correctly.  All the piping is new and clean and in good condition.  I was just worried about the safety side of using it with children in the home.


I


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## coaly (Oct 5, 2019)

Some blowers have oil holes where a few drops a year prevents bearing failure. Others have sealed bearings. Look at both ends of the blower motor carefully.

At a minimum check the chimney flue for obstructions, we don't know if there is a screen on the top to prevent any thing from building nests in there, of it there is any creosote formation.

Fuel for a beginner (or anyone) is important to have seasoned (dried) correctly in advance.
Invest in a moisture meter, don't expect if buying "seasoned wood" that it is truly dry and ready to burn. Drying wood starts when split, not cut down or in rounds. Most firewood sellers would not have room to cut, split and store it correctly (off the ground) for a year or more to dry. You're looking for moisture content of 20% or less, or you will have problems.

When you go to start it, spin the air intake dampers open a few turns. This is the only time you will open them that far. As it catches, slowly close them as it comes up to temp. Add larger pieces keeping air space between all wood pieces. The more ways you divert the flame to bend around pieces, the more heat goes into the wood starting it easier. 1 turn or so is normal when up to temp, then you set them for desired heat output. Don't close them down too far trying to stretch wood or prolong overnight burns. That will load the flue with creosote quickly. You should have enough coals in the morning to build a new fire with kindling, open the air and it should take off. When you get good, you can keep it going 24/7 without needing a match to relight and never shut down to remove ash. Always burn on 1 inch ash minimum !
Best cycle for constant burning is each morning remove ash at the front where it burns down to very fine powder behind the intakes. Rake coals and a little ash ahead to start the new fire. Black pieces at the rear are charcoal, with a very low ignition temp to help get it started again. They don't burn due to lack of oxygen. If you get none, you had a bit too much air, burned it completely and possibly no coals either.

 The Duration of a fire is considered if it will relight without a match. It will not be putting out much heat at the end of a long burn, but it is still considered the same burn until a match is needed. No one can tell you exactly how to run it since the chimney is the unknown factor, as well as changing air pressure and outside temperature which increases the draft naturally as it gets colder. You will find they are very sluggish when a storm approaches with a low pressure area, as well as warm days when the chimney doesn't have enough differential temperature to make it go. It takes years to learn each stove and chimney combination, so you will always be improving as you go. Don't expect to learn it overnight. Keep the basics in mind of what makes it go;  heat in the chimney creating a vacuum in the stove to get oxygen to the fire.


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## Ejraste (Oct 7, 2019)

coaly said:


> Some blowers have oil holes where a few drops a year prevents bearing failure. Others have sealed bearings. Look at both ends of the blower motor carefully.
> 
> At a minimum check the chimney flue for obstructions, we don't know if there is a screen on the top to prevent any thing from building nests in there, of it there is any creosote formation.
> 
> ...



Another quick question. My home insurance got back to me and said that my wood stove needs a thimble, which needs to be 12 inches larger in diameter than the stove pipe. I didn't think I needed a thimble if it's going through a non combustible wall? What is my easiest and cheapest way to accomplish this? Thanks


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## coaly (Oct 8, 2019)

That is absurd. Ask them if they are trying to prevent your cement blocks from catching on fire. (and to show you that requirement)

The reason for thimbles with airspace between multiple layers of pipe is reducing clearance to combustible materials. Keyword combustible.

I would be more concerned if the supply heat duct pipe is galvanized. At high temperatures it gives off toxic fumes, and I don't like to see paper faced insulation exposed around heating equipment.

The taped joints on the connector pipe is also unnecessary unless there were huge gaps. _Tells me the blower may be putting the basement in a low pressure area and smoke leaked in from the joints. _In operation, when the chimney is warmed, hot rising gasses cause a low pressure area inside the chimney flue, connector pipe and stove. This is the cause of "draft". This allows atmospheric air pressure to PUSH into the stove feeding oxygen to the fire. If the blower intake on stove is not ducted to the heated area, the blower tries to make a vacuum in the closed basement. This lower pressure overpowers the chimney draft. This is why I questioned if it was ducted properly. It's not normal to see people tape and seal pipe joints unless there was a problem. Any leaks allow indoor air to leak INTO the chimney, not out. There should always be higher pressure outside of the chimney that inside. Leaks cool the flue decreasing draft, so only when the leak is extreme does it need to be sealed. Look at the blower to see if it has an intake screen or if it is ducted with pipe or hose like dryer vent to the upstairs heated area. If it's sucking air from the basement, codes require any heated area to have return air from the source. You can't pump hot air into a room without returning the cool air back to the source. The furnace (looks to be air handler in your case) should have return air ducts into each room as well, they are probably considering that to be return air, but possibly someone added the stove after the air handler was installed, and should return the upstairs cool air back to the stove blower intake. (If you have a gas water heater, any dryer or other vented equipment in the basement, they all depressurize the area the stove is in, competing with the chimney as well - this affects the air intake on the stove, not allowing atmospheric air pressure to in to make it work) I notice what looks like an air vent on the return duct to the right of air handler. This shows the air handler also conditions the space the stove is in? If not, that intake will depressurize the basement when on and open. Without return air, blowers try to pressurize the building, leaks out everywhere, and is not efficient at all. That's a little above the mentality of your insurance company.


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## TWoods (Oct 8, 2019)

I agree with Coaly.   However, If they are stuck on this and you don't want to get a new insurance company, one avenue may be to get your local town building inspector out there and have them give you a certificate of installation.    So long as you follow local building code, then you are fine.    Then you can just send them the form and the insurance clerk will be happy.

Or just get a


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## TWoods (Oct 8, 2019)

Sorry, I hit the post button before I was done.  Meant to finish with:

"Or just get a new insurance company."


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