CFM suddenly quit burning...

Codeman812 said:

If it is the same model as mine ( I got it at Lowe's) then there is primary air coming out in the center at just below the door as well.

Jimbob said:

Yep that's the air wash. It directs the intake air over the glass, to keep it clean. On that stove, probably all the primary air comes in that way.

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I just looked at it and cannot find an air inlet below the door. When the door closes, it sits atop a horizontal piece of metal that goes into the stove about 2" and then turns down about 1/2". There is a space underneath this horizontal piece where a LOT of ash has collected, since it isn't really visible or accessible to a normal shovelling. I pulled out all the ash and felt around all over the place but cannot find anything resembling an air inlet either from the inside or the outside of the stove. This doesn't mean much, though, since I misunderstood the upper air inlet the first time I looked at it. The upper air inlet appears sealed except for the air wash lip, so it doesn't appear to connect to anything beneath the door. I don't see any other way for air to get in. Am I overlooking something, or are our stoves different? My stove model/date # is FW300010. Not sure what part of that code could possibly indicate a date.

Codeman812 said:

We have the same model stove. underneath the door is a space that does collect a bunch of ash ans is hard to get to with a shovel. I use a metal putty knife when the stove is cool, well warm, ok not blazing. if you start on the outsides and trace towards the middle/center the gap is broken up by the inlet "box." The inlet is actually just a hole drilled into that box from what I remember. My stove is way to hot to stick my head in and look right now Not a whole lot of air comes in through it but I do keep a trench in the coals in front of it when I have an E-W load in. I run E-W most of the time. To run N-S the wood has to be a minimum of 14". Please keep us posted as I am still curious as to what the problem is. I am leaning to that sound you heard, but until you can either see up the chimney or look down you wont know for sure.
I also looked at my stove as it sits hear way too hot to investigate further and wonder how air gets to that inlet. I know I have seen a little after burner flame come from it occasionally. Maybe it is secondary, which I highly doubt because I can trace the secondary air route very easily from the back to the tubes. Additionally I notice that the primary air control seems to have an effect on it.

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okay, thank you, I found it. I'm going to see if I can fire it up, since there was lots of ash there. I doubt this was the problem, but consider it's worth a shot if it keeps me off my ten-slope roof in the pouring rain tomorrow.

also I notice you have your stove model number in your sig file, looked right past that before. Sorry.

conspiracy for that?

Dick Cheney did it. The free wood actually means very little since I can only use what standing deadwood I can push over, throw in my truck, and cut with the cheapo miter saw. Makes me feel better to have it in the sig?

Fire didn't go; there is just no updraft at all. I can't even hear any wind in the stack. Up to the roof tomorrow I guess.

Okay, the plot sickens. My flue installation guys told me they had not installed a spark arrestor screen. They suggested that before going onto roof I raise the flue from the stove and look up into it to see if I can see daylight and air. I can see a nice round circle of daylight (indirect daylight hitting the underside of the cap, I guess) with a slight buildup of black specks on it (not bad, don't see how it could be clogging anything since light obviously getting in and I can feel airflow in the flue as well.

I could be wrong but I think this eliminates the flue and / or flue cap as the source of the problem.

So here's where I stand:
Both air inlets are clear and operational.
Flue appears to be operational.
I can't feel or see any obvious obstructions in the secondary burn chamber, but I believe that this has to be where the problem is, since above problems have been eliminated. Perhaps the baffles are clogged (???) or the air supply to the secondary burn chamber, if there is one, is clogged??? The stove guy said that maybe the air intake for the main firebox also supplied air to the baffles, but I don't see how this could be. I'm thinking it's probably time to try to call the stove manufacturer, unless someone here has a better idea.

Other things it would help to know/investigate:
1. how air gets into the secondary burn chamber (someone mentioned a channel running up the middle of the back of teh stove so I guess I'll remove firebrick and look for this)
2. exactly how the baffles work & if there could be a problem there. I am still so ignorant about this stove thqt I don't know exactly how the baffles work and whether or not they have anything to do with the secondary burn chamber or just reside in the first one.

I am learning slowly, lol. I just hope that I can get the stove working again. If I succeed, I will understand the workings of it much better and might be able to help someone else with a similar problem. I just thatnk all who have responded so far ; you have all been very generous with your help and I really, really appreciate it!

CountryGal said:

Good luck! You must be very frustrated. Did you ever find out what might have made the 'clunking' sound you heard?

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Thank you, and no, though it must have been something outside of the flue, inthe attic, because I have opened the flue and there are no obstructions. This stove thing is not the biggest frustration I have right now, lol. Sick parents in bad situationIt will get fixed somehow.

Okay, installment #20: I called CFM technical support and told them about the trouble and the steps I had taken so far to try to diagnose the problem. The rep started out by telling me that I was by far the most educated and knowledgeable person (about the stove) she had ever tried to help. I burst out laughing, told her I really didn't know anything about the stove, and that all the knowledge came from hearth.com. She asked me about the seals (OK), if the baffle was pushed all the way to the rear (yes), and said that she really couldn't think of anything else that could be checked because she didn't believe there could possibly be a problem with the air supply to the secondary burn chamber or with the baffles, etc. She then asked me about the buildup in the flue (very thin, can scrape off with fingernail like scraping plaque off teeth, sorry for the image) and how I built a fire, type of wood, etc. Lastly she said, after admitting that she was stumped, that the problem could be environmental . Little bells started going off in my head at that point because:

The first time I called the folks who installed my flue about this problem, I also asked why they had speced out a taller flue than was actually installed. I was concerned that my flue didn't meet the 10-2 rule, but appeared to terminate at the same height as two adjacent roof peaks (the flue itself rises out of a valley) that are each about 6 feet from it. His response was that the flue wasn't violating any building code, that that was only a variable guideline for getting a good draft, and that as long as it was drafting well then the flue was tall enough.

After hearing this, Leah at CFM told me that the 10-2 rule was mandatory for good draft, and that if we'd had a weather change in the past week, the valley could easily be creating a downdraft into the flue.

I called my flue installer back to tell him this and he got very angry with me, and told me that there was no way the flue could draft well and suddenly stop drafting properly due to a change in temp or atmospheric pressure. Finally he reluctantly agreed to talk to his guys about getting back out here and lengthening my stack. I don't know why he was so P.O.'ed about it unless 1)he doesn't like being disagreed with by an ignorant fool like me or 2) they won't make much money off the adjustment.

So... does anyone think the problem could be the height of my flue? Is it really possible for a flue to work beautifully in some weather and horribly if the wind direction changes (and it just did here) or the pressure changes? The extra pipe will be $200 but will certainly be worth it if it fixes the problem.

BTW I told Leah at CFM that I would tell other CFM product users on here to ask for her when calling tech support.

jtp10181 said:

If your flue terminates at a point where the roof is within 6ft is definatly does not meet the 2/10 rule. I belive the 2/10 rule is in the NFPA 211 code book, which I thought was a nationally recognized code for chimneys and fireplaces. http://www.nfpa.org/aboutthecodes/AboutTheCodes.asp?DocNum=211&cookie;_test=1

Basically... IMO they should be making your chimney code complaint for little or NO money. Do you have a signed contract for them to install the fireplace and flue at a certain price? If you do and it is not installed to code I would expect they repair it at no charge. It is their mistake for not doing it correctly in the first place. I would not expect a customer to pay for us to fix our own mistakes which happens every once and a while.

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The flue was speced out to be higher originally. I don't know why the guys elected not to install the last length of pipe, but they did take $182 or so off their original estimate. I would expect to pay this much, no more, for them to lengthen it. I am still more concerned about getting my stove burning again than about the money.

Actually it makes more sense to wait (to get the chimney lengthened) until the weather changes again, try some of the draft tricks, & see if it improves. If it does, then I think I'll have my answer. I still don't know if this is the problem.

I'm not at home these few days or I'd give it a shot. Tomorrow maybe.

HOORAY Eureka (etc.) My stove is not broken, my flue is indeed too short. After unloading a truckload of deadwood, cutting up 2 truckloads of deadwood (we're expecting snow tomorrow), then wrestling the flue back onto the stove (the difficult part is not raising it, but putting it back together), warming the flue before lighting, etc... I now having a ROARING fire.

I was also skeptical that a simple weather change could so drastically reverse my draft, but apparently it did. The wind direction during those sev eral days I couldn't get a fire going was directly into the valley where the stack sits; maybe a turbulence expert could explain why this created such a strong downdraft.

I'll admit I feel silly for not having figured this out to start with, but it was such a dramatic reversal (literally) that I hadn't encountered it in the previous 7 weeks of burning. I will call my installers Monday & get them to come lengthen the flue. Meanwhile working through this, thanks to you guys, I did learn quite a bit about my stove and am sure this knowledge will come in handy later on.

Thanks, so much, for all your suggestions and help.