Century CW2500 - Did I make a Mistake?

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wrxtance

Member
Sep 3, 2010
44
NW CT
Pretty regular lurker here - I've already learned a lot from this site and I'm hoping for a bit of advice and perhaps real-experience.

Previous experience is with a 1980's Silent Flame model 1662 insert that came with the house when we bout it a bit over a year ago. Last winter we heated the main part of our house exclusively with this insert. The thing chewed through wood and heated the house in spurts of intense heat followed by a dead fire - its burn for maybe 6 hours max with 5-6 average size splits. The stove was either "ON" or "OFF" despite my efforts to replace door seals, etc. - I had it sealed as good as it ever was. It did not have a chimney liner (was simply slid into the masonry opening - scary) but I imagine that might only cause it to eat more wood. Specs list this stove as the following:

Low fire - 2400 BTU/hr - 63% efficiency
Med fire - 30500 BTU/hr - 48% efficiency
High fire - 156000 BTU/hr - 37% efficiency

I would imagine we usually ran the stove between a Med and High fire.

Anyhow, long story short, late this summer I purchased a Century Heating CW2500 stove from northern tool to replace this old insert. This stove is rated at 65000BTU/hr max output which seemed like it might be a good fit to heat our 1500 or so square feet of main house. Did the liner, etc. - install was actually fairly trouble free. Liner is not insulated mainly because I was on a pretty tight budget.

So, with the CW2500, I am having a hard time believing that this stove is going to heat the house based on the few test fires (5 or 6) I've had. I feel like my draft is good and I'm running the stove "almost" properly at this point. No matter what I do, I can't really get the stove to fire much above 450F stove temp. I do suspect my wood is a bit damp due to the rainy summer but a MM reading is usually below 165 at the ends (haven't split any yet to check inside moisture). If I run the stove with the primary air wide open, I can barely break the 400F mark - damper 1/2 open I can get the temps to build more. From reading here, this seems somewhat typical but a bit counter-intuitive. Of course, I learn recently that the specs of this stove were a bit under-rated 1.5 cu.ft firebox rather than the previously advertised 2.0 which isn't helping ease my mind. I love the stove but I'm a bit worried about its actual heating capacity.

Are we going to freeze this winter? Am i doing something wrong? Anybody here successfully heat 1500sqft with a stove of this size/type/BTU rating?

Any help and advice is welcome. Thanks in advance!
 
wrxtance said:
Pretty regular lurker here - I've already learned a lot from this site and I'm hoping for a bit of advice and perhaps real-experience.

Previous experience is with a 1980's Silent Flame model 1662 insert that came with the house when we bout it a bit over a year ago. Last winter we heated the main part of our house exclusively with this insert. The thing chewed through wood and heated the house in spurts of intense heat followed by a dead fire - its burn for maybe 6 hours max with 5-6 average size splits. The stove was either "ON" or "OFF" despite my efforts to replace door seals, etc. - I had it sealed as good as it ever was. It did not have a chimney liner (was simply slid into the masonry opening - scary) but I imagine that might only cause it to eat more wood. Specs list this stove as the following:

Low fire - 2400 BTU/hr - 63% efficiency
Med fire - 30500 BTU/hr - 48% efficiency
High fire - 156000 BTU/hr - 37% efficiency

I would imagine we usually ran the stove between a Med and High fire.

Anyhow, long story short, late this summer I purchased a Century Heating CW2500 stove from northern tool to replace this old insert. This stove is rated at 65000BTU/hr max output which seemed like it might be a good fit to heat our 1500 or so square feet of main house. Did the liner, etc. - install was actually fairly trouble free. Liner is not insulated mainly because I was on a pretty tight budget.

So, with the CW2500, I am having a hard time believing that this stove is going to heat the house based on the few test fires 95 or 6) I've had. I feel like my draft is good and I'm running the stove "almost" properly at this point. No matter what I do, I can't really get the stove to fire much above 450F stove temp. I do suspect my wood is a bit damp due to the rainy summer but a MM reading is usually below 165 at the ends (haven't split any yet to check inside moisture). If I run the stove with the primary air wide open, I can barely break the 400F mark - damper 1/2 open I can get the temps to build more. From reading here, this seems somewhat typical but a bit counter-intuitive. Of course, I learn recently that the specs of this stove were a bit under-rated 1.5 cu.ft firebox rather than the previously advertised 2.0 which isn't helping ease my mind. I love the stove but I'm a bit worried about its actual heating capacity.

Are we going to freeze this winter? Am i doing something wrong? Anybody here successfully heat 1500sqft with a stove of this size/type/BTU rating?

Any help and advice is welcome. Thanks in advance!
Click to expand...

Welcome to the forum wrx! I suspect your wood may be a factor and I suggest you try to obtain some dry wood or mix in some eco-logs or similar and see what happens.. Your stove has a 1.45 cu. ft. firebox and that's a bit on the small side and less wood equals shorter burn time and less btu's.. Good dry wood will make a big difference so see if you can find some and give it a whirl.. Good luck and keep us posted on what you find.. Oh one more thing, a blower is a must with inserts to get that heat out and a blockoff plate insulated with Roxul above it will keep the cold air out too..

Good Luck!

Ray
 
Split the wood and check on the freshly split face. This sounds like damp wood. The firebox size on the stove is over-rated so maybe it won't heat the house in the coldest weather, but it should make a very nice difference. I would expect it to get up to 600F with dry wood. Try adding some construction cut offs or other known dry wood and see if that makes a big difference.
 
+1 on block off plate, dry wood & Roxul.

If you don't have a liner I definitely suggest you get one. The MFG does not guarantee performance without it. I know I work for Century. How's your secondaries kicking in? That's a good indication of what's happening with your fuel. If you've got no or little secondaries after 15 min to 1/2 hour you have an issue with either fuel or draft.

The unit comes with a blower.

Let me know if you have any questions.
 
I think the above posters hit it. I will simply put these in order.

1.) check your wood (internally) for %MC - your fuel sounds suspicious.
2.) when you installed the liner, did you use a block off plate above the stove (and insulate)?
3.) 1.45 cuft fire box is small. The 65000 btu# was probably obtained from an all out "full burn". At 1.45 cuft and 65000 btu output, your probably going to have short burn cycles.
4.) The insert you have now is only capable of less than half the output of the old one, according to your numbers. Just say'in.
5.) Are you using the blower?

Welcome to the forum and stick around. We will help you obtain the best performance out of that new box that can be expected.
 
Thanks for the suggestions.

I do have a chimney liner (though it is not insulated)
I do have a blockoff plate that is insulated with roxul
I also have roxul at the TOP of the chimney below the cap to trap hot air in the masonry
I also have a slab of roxul on top of the inserts heater box
The blower is hooked up and working - it does move volume but certainly not much velocity. Probably fine though.

My secondary burn seems to be working - I notice them start burning at about 250-300F stove temp. The more I shut the intake, the more secondary I get - makes sense. With primary air open more, I get very yellow secondary burn. With it more closed, I get more orange and blue secondary burn.

Unfortunately for me, I too am leaning towards the wood as my main issue here and I am going to have to work through it somehow. Damn mother nature for all this rain!

Last night I really pre-warmed the stove to about 400f with kindling and damper wide open. Got a small load of wood up to about 500F within about 30min and damper 1/4-1/2 open. If I run more air, the temp goes down rather than the fire taking off more - correct me if I am wrong but this is probably confirming the wet wood issue?

My previous stove would burn green wood so I am not that skilled in the fine art of woodburning quite as much as I need to be... but having fun learning.

p.s. - I should also state that I feel like my post title may be a bit misleading. I really do like the Century stove - its well built, looks nice, and was an unbelievable price. It gets great reviews both here and on Northern tools site which is why I bought it. I do hope and I think it will serve me well. The "mistake" I refer to is MY potential mistake of under-sizing a stove to my needs and/or not building a biodome over my wood for this crappy, rainy summer.
 
wrxtance said:
If I run more air, the temp goes down rather than the fire taking off more - correct me if I am wrong but this is probably confirming the wet wood issue?
Click to expand...

I suspect that this is at least part of your issue. Try and grab an armload of known dry wood (friend, store, etc.) and give that a shot. At least you will know how much the wood is/isn't affecting you. Pallet wood can also be a dry source. Be aware, pallet wood can get hot, fast. Use caution when loading and don't try and stuff it full.
 
"If I run more air, the temp goes down rather than the fire taking off more - correct me if I am wrong but this is probably confirming the wet wood issue?"


I am pretty sure this 100% normal! I found this out when almost over firing the stove. I caught it just in time and closed off the air, well..... The temp kept rising and rising and rising! I tried all I could and thought if I open the door, the heat will go up the stack. Sure enogh it did, THANK GOD!

Ps. Your stack temp probably goes WAAAAAY up though.
 
PLAYS WITH FIRE said:
"If I run more air, the temp goes down rather than the fire taking off more - correct me if I am wrong but this is probably confirming the wet wood issue?"


I am pretty sure this 100% normal! I found this out when almost over firing the stove. I caught it just in time and closed off the air, well..... The temp kept rising and rising and rising! I tried all I could and thought if I open the door, the heat will go up the stack. Sure enogh it did, THANK GOD!
Click to expand...

To a point, you are absolutely correct, But there is a point of return. In other words, If I slam my air control to its lowest setting, it will make the fire die out to a low smolder, 1/8 open, better fire, more heat. 1/4 open big fire, big heat. Get over 1/2 open and I see the same thing that you are reporting. Just say'in that air control is not written in stone. Questionable wood confuses this even more.
 
Jags said:
To a point, you are absolutely correct, But there is a point of return. In other words, If I slam my air control to its lowest setting, it will make the fire die out to a low smolder, 1/8 open, better fire, more heat. 1/4 open big fire, big heat. Get over 1/2 open and I see the same thing that you are reporting. Just say'in that air control is not written in stone. Questionable wood confuses this even more.
Click to expand...

Ok, so the temp thing makes sense to me - it goes up the stack. But, if I open the air control fully, the flame should "rage" correct? I can certainly hear the air rushing into the stove through the intake but the wood doesn't really seem to burn much faster. Yeah, the flame changes color and all that but I have yet to see a situation where I say "wow, the fire is getting too big".

I need to investigate my wood a bit more. F!
 
Where is your thermometer placed? I also have this stove and the only place I can think to put it is just above and to the left of the door (on the face, not the top of stove). You don't want it on top like most stoves because there is an air gap for hot air to blow through from the fan. I'm not sure how accurate of a temp I'm getting from this location, but I've found that with dry wood (confirmed with mm), air fully closed, and secondaries going absolutely crazy it will only get up to 500-525. I think I've got it above 550 maybe once or twice. And like you, I've also found that leaving the air open will not get any higher temps... the temps only start climbing into the good burn zone after I start closing down the air. I'm thinking that the temps are being somewhat under reported since the thermometer is right at the outside edge of the firebox.
I wonder if the front of the glass would be a better location for the thermometer?
 
Scottydont said:
Where is your thermometer placed? I also have this stove and the only place I can think to put it is just above and to the left of the door (on the face, not the top of stove). You don't want it on top like most stoves because there is an air gap for hot air to blow through from the fan. I'm not sure how accurate of a temp I'm getting from this location, but I've found that with dry wood (confirmed with mm), air fully closed, and secondaries going absolutely crazy it will only get up to 500-525. I think I've got it above 550 maybe once or twice. And like you, I've also found that leaving the air open will not get any higher temps... the temps only start climbing into the good burn zone after I start closing down the air. I'm thinking that the temps are being somewhat under reported since the thermometer is right at the outside edge of the firebox.
I wonder if the front of the glass would be a better location for the thermometer?
Click to expand...

I have my thermometer placed in a similar spot - only on the right hand upper corner just next to the air inlet control lever. I mounted it to the door surround once and temps seemed even lower.

The owners manual for the stove suggests to not burn over 840F so I am thinking I am not even close to the heating capacity of this stove which is what is making me question all of this. Not that I want to try to burn at 800F all the time but surely, 600F should be attainable which is ~20% higher than what I can get so far - thats a big difference in heat!
 
I read in a thread here recently that (as best as I can remember) a thermometer on the front of a stove registers something like 125-150 degrees less than one on the stove top. Obviously with inserts that's the only place you can put one. I have a similar size insert with a thermometer on the upper left side of the front by the door. It rarely gets over 550, even with a fully engulfed load and the secondaries rolling. The insert is cranking out a lot of heat at that temperature and can drive us out of the living room if I'm not careful. I'm agreeing with the idea that your wood is not ideal. My first year burning I had less than ideal wood and mixed it with BioBricks to get the desired heat. I like the result so much that I do it routinely now--about a 50/50 mix.
 
I have the CW2500 and locate a magnetic thermometer in the same location, top left of the door. It reads darn hot if i get a load of hedge rolling (highest BTU wood there is). This is from memory, from last year, my first year burning, but I'm pretty sure it was reading 750deg+. We got worried a few times cause it was reading so hot. The tubes were glowing too.

But, when we first started burning, I had what I thought was good wood but in fact it was not good wood, and I was getting similar results to what you are saying. I couldn't get up to temp and i couldn't maintain a temp when I got to it. You can check out my thread about my troubles last year... might not help but who knows. Everyone blamed the wood and they were right! I split my wood real small, put it in the garage with a fan on it, but it didn't help. We didn't get burning good till my brother cut down a half dozen of half dead hedge trees and I got a load of it. Even wet, that wood burned great.

https://www.hearth.com/econtent/index.php/forums/viewthread/68103/

Good luck! I trust you will figure it out..
 
Well, I checked a few pieces after a fresh split. Internal moisture is 35% or more in some cases (MM reads "OL" over 35%). I suppose I should be happy with the results I have been gettin so far based on this!

Time to hunt around for the best price on a dry cord to mix in.

What a bummer - my wood has sat split for just under a year but never got there due to weather. I plan on relocating future piles to a better drying area - paying for wood is silly...

Thanks for the help guys.
 
I see that you are in CT so you should be able to get some Biobricks locally. Buy some and mix them with your suspect wood, they are so dry that you will be able to see what the potential of your stove with a good dry fuel load will be. I may be in a minority in this forum but I love Biobricks and I burn them mixed with hardwood all winter.
 
For 1500 sq ft you should have probably gotten the CW 300010. I use one to heat my 1000 sq ft place and it works fine.
I'm not even sure mine would be sufficient in CT winters.
 
Not to throw cold water on your hopes for the CW I think you'll be hard pressed to heat 1500 sq ft with that unit. Don't know how old your house is or how sealed it is but that will play a part also.

good luck
 
wrxtance said:
Well, I checked a few pieces after a fresh split. Internal moisture is 35% or more in some cases (MM reads "OL" over 35%). I suppose I should be happy with the results I have been gettin so far based on this!

Time to hunt around for the best price on a dry cord to mix in.

What a bummer - my wood has sat split for just under a year but never got there due to weather. I plan on relocating future piles to a better drying area - paying for wood is silly...

Thanks for the help guys.
Click to expand...

While I agree free wood is good I pay for my wood csd and it costs me about $550.00 a yr... I stack my wood in a couple days and I am done until the spring when I reload the shelter.. To me I'd rather pay for it and I can work a little OT to pay for it and it's much easier to work than cut and split wood and it takes much longer to cut and split 3 cords than the OT.. I do like to add a little of what I get given to me and that works for me..

Ray
 
I'm using the CW2500 for my 1500 sq ft house--it struggles to keep it at 70 when the temps get into the mid/low 20's, but can be done. My house is relatively uninsulated cinder block, good windows, good attic insulation. It's also a second home that I keep at 40' when I'm not there, so it's always an uphill battle. I heated last year with mediocre pine. I've found the temps on the front of the stove to vary widely, depending on how the wood is loaded. I started using a meat thermometer clipped to the upper edge, so the probe is sitting in the airspace. This temp is a lot more consistent (I purchased a candy thermometer like this
518Ca3-i9ZL._AA300_.jpg
with a better scale). With decent wood, I run at about 230' when cranking. I have some dry wood this year, and insulated the chimney, so I'm curious to see if there's an improvement this year...
 
Our house is a 1.5 story cape. Stairway to the upper floor is attached to the room with the stove in it. We have an additional 5-600sqft to heat on the first floor - we have a pellet stove in there.

With better wood, I feel semi- confident that this stove will keep up but I'm starting to feel not-so-good about the firebox size. My understanding of "burn time" was different than what the manufacturer does too so the 4-6 hour range advertised for this stove isnt really true "burn time" it's more like "hot time".

Oh well, I'll do what I can. My chimney liner is good and the stove was $700 so if I have to upgrade to something bigger next year, it won't be a huge waste.
 
That's the spirit. For sure you are going to be more comfortable and will experience lower fuel bills. Please stay on board and let us know your experiences as you and the wood get more seasoned over the winter.
 
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