Need Advice - Insulate the liner or extend the chimney height

[norwich]

I had a Jotul 350 Winterport installed about 5 weeks ago. The dealer told me I would not need a full liner. However I elected to have a 6" full liner installed. I wanted to make sure I had no issues. The liner is installed in a 12x12 clay liner. The fireplace is a heatilator (brick chimney, metal fire box). The chimney is external (it is enclosed in an insulated but unheated garage). The minimum height recommendation for this stove is 15'. My chimney is a little over 15' feet and the dealer nor the installer saw any issues. However now I realize that this measurement should be taken from the top of the stove to the top of the chimney. That means my chimney is a few feet shy of the recommended 15 ft. When the insert was installed I had some well seasoned wood (stacked over three years ago). Being a new wood burner I am sure I still have a lot to learn. So I would not be surprised if some of my struggles are due to inexperience. However I have been doing a lot of reading in this forum to learn as much as I can. Using the well seasoned wood I was able to get some good hot fires and generate some good heat off the stove. I still struggled from time to time but I was able to enjoy the stove and get some secondary burn. Under ideal conditions I seem to be able to get a good burning fire. When that well seasoned wood was gone I ordered a cord of "seasoned wood". Well I learned my lesson that it is not really possible to buy seasoned wood, at least in the middle of the season. So I learned a good lesson and I will be better prepared next year.

I have a friend who burns 24x7. He has been using a wood stove for 20+ years. I borrowed some wood from him, so I know the wood is seasoned. He is using this wood with no problems. However I am still struggling. I am not sure if I have a draft problem, a chimney height issue, a wood issue, and experienced user issue or all of the above. I do have a slight downdraft issue. When starting a fire I do get some smoke coming into the room. But this is solved by opening a window for a minute or so when starting the fire. Keeping the door of the stove slightly opened I can get a good fire started using kindling and some small splits. I burn this down to coals and put in some larger splits. When everything goes well I am able to get a good hot fire burning and even some secondary burn within an hour. I can get a few hours of a good burning fire. However as it starts to cool off it becomes more and more difficult to maintain the fire. Other times I can burn for hours and struggle the whole time, constantly needing to tend the fire to keep it burning. However never getting hot enough to get secondary burn going. I would assume this is an issue with the wood, but my friend is burning this same wood without any issues. If I can keep a good hot fire burning it will work well, however I feel I am struggling too much to maintain a good hot fire. Without the absolute best conditions (very well seasoned wood) I end up struggling to keep a good fire burning.

The dealer has not been very helpful. They say there is not much that can go wrong. I just need to get used to it. However I continue to do a lot of reading in the forum and I believe I must be dong something wrong or I have a problem and I need to identify what the problem is. I had a chimney company come by to give me some advice. They suggested it may be an issue with the height of the chimney or the fact that the liner is not insulated. They have suggested that I should have the liner insulated and hope that will resolve the issue. They feel the volume of the chimney is difficult to heat and the insulated liner will help. If not then try to raise the height of the chimney. I wanted to ask your advice. The two options for insulating the flue are:

1. Leave the 6" ss liner in place and insulate around the liner using Thermix Chimney insulation for $550.00. This would be permanent. I would not be able to remove the liner in the future as the insulation would harden around the liner.

2. Pull the 6" ss liner wrap the liner in using foil faced ceramic insulation blanket and reinstall the insulated liner into the 12x12 flue for $750.00

I wanted to ask what you thought about the options presented. Do you think I should insulate the chimney? Should I go with the XXXX or the XXX? What do you think about the estimates to insulate the chimney? Should I raise the height of the chimney instead? Should I insulate and raise the height of the chimney? Should I get more experience burning before I try any of these options? Do you have any other ideas? I am open to any suggestions. Your help is appreciated. if you need any additional details please let me know. Thank you.

 

[webbie]

My first thought is that height is needed as much, or more, than insulation - of course, insulations also helps.

But, for example, if you still have problems on a 45 or 50 degree day when the chimney is reasonably warmed up, this would indicate more of a height problem. Being as your chimney is a big short of the suggested 15+ feet), this makes even more sense.

Not sure if you are familiar with my little inventions, but I came up with some cast aluminum extension that can be installed at the top of the chimney and your liner extended up through these. See the cc1212 at:
http://www.extendaflue.com/cast.html

You would need the castings only, and then run some stainless up through them to an adapter. My thinking is that extending and at the same time insulating the pipe in the extension and maybe a foot or two down (without pulling the liner) might give you the best of both worlds - some extension and some insulation.

It is frustrating to have a poor draft, as draft is what makes things happen.

 

[Hogwildz]

Get yourself a 4' section of 6" galvanized at Home Depot or Lowes. Temporarily attach it to the top of your existing liner. See if that improves the problem. If it does, extend the liner with an appropriate section of s.s. rigid attached to the existing liner. If it does not improve that much, may want to consider insulating the liner.

 

[norwich]

Thank you for the suggestions. It has been an interesting weekend weather wise here and I wanted to post some observations and a couple fo follow on questions. The weather this weekend started off with heavy rain on Friday evening all day Saturday and Saturday night. I believe we received over 2.5" of rain. Today (Sunday) it is sunny but very high winds. Temperatures for the weekend have been in the 40's. Reading your comments above made a lot of sense and I thought the weather this weekend might uncover some more clues for me. So i have been burning all weekend to see if I can notice any differences. I have been using some of the seasoned wood I borrowed from my friend, some "kiln dried" wood I picked up from Lowes (a small bundle) to get the fire going in the morning and some Envi-Blocks (to try to eliminate the cause of my issues being unseasoned wood). Based on my observations it does appear to be easier to burn with the warmer temperatures (40's). I am able to get a good hot fire going and maintain it longer. I would still like to see some better performance from the stove but if I load it up it is burning well.

So I am wondering what your thoughts are based on the performance of the stove this weekend, considering the weather conditions (40's, lots of rain, and now high winds 25+ mph gusts). Today (Sunday) with the high winds the fire is maintaining. Would you consider this to be an indication that the chimney (while shorter then Jotul recommendation) is adequate and I should really be focusing on insulating the chimney? Or is this wishful thinking (that I might actually have a solution)?

Any thoughts on the cost estimates for the two insulating options suggested by the chimney company? Are these estimates reasonable? Any thoughts on the right way to go (pull the liner and wrap it or fill the cavity with the Trermix Insulating). I also like the idea of trying to temporarily extend the height of the chimney to see if that makes a difference. I may try that also. But I wanted to get more advice based on this weekends performance. Any other thoughts? Thank you for your advice.

 

[JimmyMood]

Norwich,

I also have a 350 with a shortish exterior masonry chimney. It measures about 18' from the top to the foundation which leaves me very close to 15' from the top of the stove.

I have found there is sort of a critical mass of heat necessary to get this burning right, I don't know if it is the chimney on the lower end of the recommended height or if I could be doing something different when starting/building a fire. This stove seems to like smaller splits than I typically get delivered. For reference, if the pieces aren't small enough to get about 4-5 pieces into the stove when I reload, they won't burn right. Maybe if your friends stove is bigger, your trying to burn pieces that are too big? If it gets hot enough to make me squint when I open the door, I can throw in bigger pieces. I keep about a 1/2 inch of ash in the bottom at all times, it seems to burn better that way.

I start a fire with the door wide open until the kindling is engulfed. When I reload, I leave the handle only half closed to let in some extra air until the wood is blackened, then I close the handle all the way. About 10 minutes after fully shutting the door, I can usually turn down the air control. Most of the time, if I don't leave the door handle cracked to get it going, mostly just smoke and smolder and won't start burning until it is almost coals. I have sort of come to accept that leaving the door cracked to start a fire is the way this unit operates. I never had any problems with smoke comming out the door until a big gust of wind came by today while I was reloading.

I would definitely be interested in hearing about what solutions you find (such as the extenders) to make this thing burn better.

 

[norwich]

JimmyMood,

I would love to share experiences with you on the 350. I love the stove even though I am struggling a little bit. Glad to hear I am in good company re: chimney height. I may have a couple of other factors contributing as well. The room that I have the 350 in is sort of a breeze way type room between the kitchen and a two car garage. The chimney is 12 feet from the roof on the main house and is 10 feet from the peak of the roof on the garage. Also in the back of my house there is a hill. So it possible that these conditions are effecting my draft situation even more so than the height issue. From all the research I have done so far I am leaning towards raising the height of the chimney. The extend a flue was mentioned in an earlier post. That looks like a great idea. However it would not be appropriate for the style of my house or the location of the chimney. I think they look great but would not be the right look for my house. So if I need to raise the chimney height I will need a mason to do the work. The chimney could use some re-pointing anyway, so this may be the answer. However I want to try a test to determine if this will help. So I am taking an earlier suggestion and I am going to extend the chimney temporarily to see if this will help. I ordered a two foot double lined stainless steel chimney pipe. I am going to use this to temporarily raise the height of the chimney to see of things improve. I will let you know the results.

I would also be interested in hearing more about your burning experiences. Your response was very helpful. Do you measure the temperature of your stove? If you do where do you put the thermometer? I have tried on the cast iron face just above the door, but this does not seem to be a true reading. I have also tried placing a thermometer on the opening where the air flow is exiting the stove (when the blower is on). I saw this on a prior post on the Jotul 550. This seems to be a more accurate reading although difficult to see at times. The front stove temperature only goes to 250-300 when burning well. The temperature in the other location will get up to 700. I am curious about your experiences.

Also your comment on the amount of wood you are using is interesting. I have a very small amount of seasoned wood left. I split it up and use it to start the fire and get a good coal base. Then I am using the Envi Blocks. When I first got the stove I had some great wood and I was only burning 3 or maybe 4 6" splits. I do not think I have ever really packed the stove. As this is new to me I was concerned with over firing it. However maybe I have been too careful. I will try burning more wood to see what I experience. Eventually my goal is to burn 24x7. I have read some threads by Jotul 550 users who burn 24x7 and only load their stoves three times a day. I would love to get there. At present my stove takes much more tending to than 3 times a day. But I am hoping the chimney work I do will change that. How long can you burn without tending (adding more wood or moving wood around to get a better burn) are you able to get?

As I go through this process I will update you with my progress. I would be very interested to hear more of your experiences, tips, suggestions regarding the Jotul 350. Thank you.

 

[JimmyMood]

I was just cleaning out my Inbox and realized I never followed up here.

I have yet to find any good way to put a thermometer on this stove. The trim above the door is part of the main air intake manifold, so I doubt you'll get a good reading there because cool room air is flowing through that piece. Overfiring hasn't been a concern, I have yet to get fire I can't safely throttle with the air control. I have had some good fires where the whole box is full of burning flame rolling off the top of the box into up into the baffle and down over the window, it was cookin'.

As far as burn time, I haven't managed to keep a flame for more than a few hours. That is if it is fully packed and lights off nice to let me close down the air control early into the burn. I can sometimes keep enough coals overnight to restart in the morning with kindling and small splits, but that can be iffy. I'm not sure if I'm doing something wrong or not. The specs say it should burn for 7 hours, but I suppose that depends on their definition of burning. I'm reasonably certain you'd need a bigger stove to burn 24x7. For what it is worth, I think I measured the firebox to be about 1.3 to 1.4 useful cubic feet of volume. Let me know how it goes with the chimney extension.