CFM FW240007 info needed

[albertj03]

Hello, I just found this site today and it looks like there is a lot of great info here. I bought a CFM FW240007 at Lowes 3 years ago. I had never heated with wood before but knew I wanted to when my wife and I built our new house. The stove was the right price (very inexpensive) and seemed look good for what I initially intended it for which was putting it my basement and just burning on the weekends. After burning about half a cord I was hooked and now that I work from home I was able to run the stove all week long last winter. I'm planning to do the same this winter. For being a small inexpensive stove it does a great job heating my basement and the warm air raises up to my first floor warming it nicely.

I'm planning on burning all winter long again and have about 3.5 cords of harwood that I cut off my 30 acres ready to go. Can anyone tell me anything about the very inexpensive CFM FW240007? It throws off great heat but since it's small I find myself reloading about once an hour. I'll load it and cut the air off before going to bed and it will keep the 1st floor from getting really cold in the morning. I'm not sure if it's me or not but it does to burn hot and fast even with air down at 1/4. Is this normal for this stove?

Thanks

 

[albertj03]

I did a search here on my stove (should have done this first) and found a thread about air coming in from the ash draw. This seems like it could be the cause of my lack of ability to really control the fire and therefore burning wood too fast (1 hour cycles!). I'm going to check this out tomorrow and possibly seal around this brick. If anyone has any suggestions or has the same stove with longer burn rates I'd appreciate your feedback.

Thanks

 

[BrotherBart]

Several people on the forum have the stove and should be along to advise how to load and burn in it.

 

[fossil]

I have the stove in my workshop. Mine's the pedestal model with the ash drawer beneath the firebox. I never use the ash drawer. I just leave the firebrick in place in the firebox floor, and when I need to remove ashes, I shovel them out the door into a bucket. This is a small stove...firebox is something like 1.25 ft³, maybe smaller. You really can't expect too much in terms of long burn times from such a small stove, because there's only so much fuel you can pack in there. I find with mine, that when I get a nice burn going with a fairly full firebox, I can shut the primary air completely and enjoy watching the secondary for quite a while before starting to bump the primary back open to keep the cycle going. Just how long "quite a while" is depends on the fuel and how much I managed to cram in there. Probably never longer than a couple of hours (although useful heat would certainly continue for some time beyond that)...but it's also important to mention that I burn almost exclusively softwoods. Since mine's a shop stove, and my wife hasn't (yet) made me spend the night in my shop, I've never tried to get an overnight burn out of it. I'm typically right there with it, and tossing wood in as needed to keep a consistent burn during the time I'm out there. This little stove excels in that environment. Rick

 

[albertj03]

Thanks for the info. When you say you're watching the secondary burn what exactly do you mean? Is it the flames at the top of the fire box? Also, does your stove ever make noises when it's heating up? Sometimes mine will make "tink...tink...tink" sounds after I've loaded it. What size pieces of wood do you put in it? I burn a mix of maple, red oak, white oak, birch, beach that is seasoned anywhere from 8 to 12 months.

 

[fossil]

Are you sure you've got the two firebricks that form most of the baffle space in the ceiling of the firebox installed correctly? They're just a bit tricky to install, and the documentation that comes with the stove is pretty sketchy on it. I think I used to have a picture of mine, I'll look for it. If not, I can take another one. If those two bricks aren't placed properly, the stove isn't going to perform worth a damn. Rick

 

[fossil]

Of course it "tinks". It's just a big steel box with steel pipes connected to it. It tinks heating up, it tinks cooling down. So does my Harley. So does your car. Everything that's a metal system that's undergoing a temperature transient tinks. Couldn't find my old pic of the baffle bricks...I'll go take another one. Yes, the secondaries are when you've got a nice fire going and you can shut the primary and the flames dance around the top of the box, and jets of flame are being burned into the top of the fuel. It's a beautiful thing. Rick

 

[albertj03]

I know they are in there but it's possible the chimney sweep who cleaned the chinmeny and stove pipe may have moved them or something. Can you tell if they are in correctly without removing the pipe? It works just the same as it always has. Throws off a lot of heat and after an hour of a fairly full load it almost close the being down to large chunks of coal. I usually have air around 1/4 to 1/2 open depending on how cold it is outside. It's a small stove so I know I'm asking it to do a lot and I think it does it well but would be great to get more time out of a burn.

 

[fossil]

Sure you can tell if they're in correctly, because you install and remove them through the door. If you open the door and look at the ceiling of the firebox, the two bricks should be neatly sitting to the left and right of the center structural member in there, closing that whole thing off except for small gaps around the edges. The bricks should be laying "North-South", with their south ends (towards you) supported by the baffle plate with all the holes in it, and on their north ends (away from you) supported by angle iron brackets on the back wall of the firebox. You should be able to see pretty much all of the bottom faces of both of those bricks. I'll take a pic tomorrow if we still need it. Rick

 

[albertj03]

It is a beautiful thing to watch those flames roar in there and this stove does give off a great show. The bottom half of my window is really dirty. I was planning to just wash it with water on a cloth. Is there something special I need to use to clean it? Is the glass being dirty a bad sign?

 

[fossil]

I use Windex & paper towel when the stove's cool, but don't need to do that very often at all. The airwash works surprisingly well in the CFM to keep the window clean. If you're getting a lot of buildup on the bottom, it might be because you're burning stuff N-S and too close to the window, or your wood isn't properly seasoned, or you're not burning it hot enough. Rick

 

[albertj03]

In the 3 years I've had it I have never cleaned the window so I guess it's probably ok. I'll break out the windex today. Thanks for all of the help.

 

[njtomatoguy]

AlbertJ03,

I heat a 796 sq ft ranch with this stove. 2br,1bath. LR is 11x13, kitchen is 12x10. It is a small stove, but works here.
I also set the furnace at 60, and if I'm diligent, it never comes on.

How many sq ft are you trying to heat with your stove?

 

[albertj03]

The house is 1,680 sqft. It's a 2 story colonial with a basement. I have the wood stove in the basement and it does a great job sending heat up to the first floor. It will usually keep the first floor around 68-69 and nice and cozy. I let the furnace heat the 2nd floor. I have to run the stove a little on the hot side to achieve this and burn more wood in the process but it does a good job. Hopefully within the next year or 2 I'll be able to get a larger stove.

 

[njtomatoguy]

Wow. Sounds like the stove is doing a great job. Anything over 72 is too warm for me.
Do you have the blower?

 

[albertj03]

No blower. The stove is right below the kitchen/dinning room and it's an open floor plan so the warm air circulates pretty well. One of the nice benefits of having the stove in the basement is the floor above it is warm which realy boosts the cozy factor. I'm also burning mostly red oak with some other good hard woods mixed in. The wood is season 8-12 months.

 

[EatenByLimestone]

I've been playing with this stove for around 4 years. It's a good little stove. The main limitation of this stove is the small firebox. I can still get a decent burn out of it though.

I'm a tinkerer by nature and the stove was only too willing a victim. You mentioned the ash drawer, I wouldn't worry about it since any blow by will be stopped by ash working it's way down into the cracks between the firebricks. As far as the bricks above the secondaries. I found there was a good deal that could be done to make it a better, more efficient stove.

The main thing I wanted to accomplish was to force all gasses and fire to travel over the secondaries. If the smoke doesn't burn it's not acting as efficient as it can. I added a second row of fire bricks above the first layer. I made sure I covered the top of the secondary feed tube and the very sides of the stove where the brick sits on the ledge. This helped by insulating the secondary tube and allowing secondary combustion faster. It also stopped the flame from licking around the stones. This worked well, but there was still leakage when the stove was cold. I ended up adding more brick covering the secondary plate and firebrick crack. Better still. Last year I stuffed kaowool in any crack the smoke could travel through and recovered the top of it with firebrick. Now all the smoke must travel over secondaries and any heat stays in the firebox longer.

You may want to check your front gasket for leaks. Sometimes ash will compress over the gasket and stop it from sealing correctly. It can cause the black at the bottom of the window you mentioned.

Matt

 

[albertj03]

I've been playing with this stove for around 4 years. It's a good little stove. The main limitation of this stove is the small firebox. I can still get a decent burn out of it though.

I'm a tinkerer by nature and the stove was only too willing a victim. You mentioned the ash drawer, I wouldn't worry about it since any blow by will be stopped by ash working it's way down into the cracks between the firebricks. As far as the bricks above the secondaries. I found there was a good deal that could be done to make it a better, more efficient stove.

The main thing I wanted to accomplish was to force all gasses and fire to travel over the secondaries. If the smoke doesn't burn it's not acting as efficient as it can. I added a second row of fire bricks above the first layer. I made sure I covered the top of the secondary feed tube and the very sides of the stove where the brick sits on the ledge. This helped by insulating the secondary tube and allowing secondary combustion faster. It also stopped the flame from licking around the stones. This worked well, but there was still leakage when the stove was cold. I ended up adding more brick covering the secondary plate and firebrick crack. Better still. Last year I stuffed kaowool in any crack the smoke could travel through and recovered the top of it with firebrick. Now all the smoke must travel over secondaries and any heat stays in the firebox longer.

You may want to check your front gasket for leaks. Sometimes ash will compress over the gasket and stop it from sealing correctly. It can cause the black at the bottom of the window you mentioned.

Matt

Thanks for the great info. I do notice flames going up into the spaces around the bricks and into the holes on the top plate. To add additional bricks into the top do you need to remove the pipe? This is a problem for me being a stove newbie, I had the stove installed professionally and wouldn't be able to reinstall it myself. Could you take a picture of your setup? With the adjustments you've made what kind of burn times do you get out of it?

This a great stove for the size and price, if I could get a little more burn time out of it it may just be the best value for the money I've ever gotten out of anything considering all the money it saved me on oil just last winter.

 

[EatenByLimestone]

I can't say I get longer burntimes from the mods. They make the heater work more efficiently... so I use less wood. If I have enough ash insulating coals in the bottom I can relight after 8 hours, but it's cutting it close. I get about 6 hours consistently. Things that I've found help burn times is of course, the pile of coals in the bottom over a nice layer of insulating ash. High btu, dense hardwoods. and maybe the most important is larger logs/splits. Small splits have a higher surface area and burn faster. Playing around and figuring out how to pile coals in your stove just tight enough to allow the air sweeping down to reignite new splits would help burn time too.

Small firebox is the bane of these little stoves. They are what they are. I walked out of Lowes with mine for $242 out the door. I happily put up with a little grief over it.

Matt

 

[albertj03]

Maybe I'm just adding wood too often. Usually I'll reload after an hour but usually there are large pieces of coal still burning. From what I've read here it seems like instead of reloading at 1 hour I should let more air in at that point to burn down the coals before putting more wood in. I'm just concerned about loosing heat during this time but I'll have t play around with it. I also may have split my wood a little on the small side last year. I have some larger splits this year so maybe that will help me get a longer burn. How often do you usually add wood to the stove? Usually before I go to bed at night I'll load the stove up and in the morning there will still be a nice hot bed of coals so I guess that is about the same as what you said (6 - 8 hours) but throughout the day how oftern are you adding wood in? This will only be my 3rd year and have pretty much taught myself so maybe I'm putting wood into the stove way too often and not letting the coals burn down enough.

 

[EatenByLimestone]

I'm not seriously burning yet. If I do burn all day (It still in the 50's during the day here) I may throw a piece on to make sure the fire stays lit. I throw wood on when it needs it. If I am trying to build up the coal bed I add wood often. If I'm trying to burn it down I add wood at longer intervals, open up the air and burn down the coals. Everybody has a different setup.

For instance, you could have a good deal more draft than I do so you could be going through wood faster...