Thanks, I actually don't have any downstream. Yes the Euro's are much better. I had someone from Efecta at my house about a month ago and he dropped off a Tigex for NP Alaska. I was going to have him bring one for me but they are very pricey and since my draft is where it is I didn't see it getting any use. With the damper out and the T capped of I am getting a reading of 0.07 which is exactly at the low end of the recommended range.
Flue Gas Temp for a Gasifier
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You are correct mostly correct - the house is not drafty but not sealed as tight as if it had been spray foamed before sheetrock was put up, just not sure how I would look into those issues, open to suggestions.
You can install an automatic fresh air damper that will open and close depending on the status of your boiler fan. Air leaks in house can be found by using smoke spray . As far as the multiple flues go you could possibly install auto dampers in them. I don't know the codes in your area. I would check into it first .
You are correct mostly correct - the house is not drafty but not sealed as tight as if it had been spray foamed before sheetrock was put up, just not sure how I would look into those issues, open to suggestions.
Thanks, I will do a little investigating on the automatic fresh air damper. Any recommendations that I should look at? Regarding the drafts, I have had 2 of those energy audits done so the air leakage into the house is minimal, I would say as good or better than any house built 1987 or older.
I've seen a post on here before of someone's auto damper. Maybe it was Jebatty or EWDudley I think.
I use a linear actuator to open a slider window 6" when the boiler draft fan turns on to provide combustion air and then closes the window when the draft fan shuts down. The window is 24" high, so 6 x 24 = 144 sq in of opening to outside air for combustion.
maple1
Minister of Fire
I think I will revise my earlier numbers. I have been checking my temps the last couple of days since this thread started, and don't think I've seen over 200c. I don't stand there watching all the time though, and likely am not there during peak burn - will try to remember to check that tomorrow. Or in an hour or so if I remember. The couch is calling though...
Thanks, mine is pretty consistent. Once I get firing well it stays about the same gas temp until the volume of wood gets to the tail end and doesn't generate as much gas. I think cleaning the tubes did the trick (at least got it under 250). I had the chimney cleaned today just to be sure but that didn't change anything, draft is still on the lower side - seems the only option left for that is a liner. I am either really close or within the low end of tagret so I think that one goes on the backburner for now. Thanks everyone for the help!
Thanks, that is a lot of sq. inches. I imagine there is a pretty simple answer but I haven't seen anyone mention the simple flap style air inlet - what is the reason that these don't do the trick? After reading a bit and thinking about my house I definitely see the need to pull in fresh air. Appreciate all of you bringing this to my attention.
Thanks everyone, the tube cleaning seemed to be the trick to get flue gas into a more comfortable range. Had the chimney clean, it was basically fine, no effect on gas flue temps or draft. I did open a window n my boiler room no change on either flue temp or draft #. Even though t had no impact, I understand the benefit and will be adding a way to get fresh air into the boiler room. Thanks for educating me on this!
BoilerMan
Minister of Fire
Other than the mentioning's of this condensing wood miser..... I am truly curious of this home-made boiler. Condensing wood has long been a goal of mine.I'm right in the same range (measured with a thermocouple in the center of the flue at the boiler exhaust).
My brother's home-made gasifier, on the other hand, runs at 120flue temp - a condensing gasifier, of all things.
On topic: My flue gas temps as measured just above the firetube HX are always in the 290-315F range, this is on an ID fan boiler. With a glowing orange refractory.
TS
Thanks, that is a lot of sq. inches. I imagine there is a pretty simple answer but I haven't seen anyone mention the simple flap style air inlet - what is the reason that these don't do the trick?
That's exactly what I'm using John. Works like a charm. Took a bit of searching online to find one that looked reasonably well-made though.
Mike
That's exactly what I'm using John. Works like a charm. Took a bit of searching online to find one that looked reasonably well-made though.
Mike
Thanks Mike. Any chance I can trouble you for a link or name/model? I have spent a bit of time searching and very surprised to not find anything. Was almost thinking that I would need to retrofit a Barometric Damper for outside use.
I'd be interested too, if you want to post the link here.
I'd like to add that most any time I open a window in the winter, cold air comes in. More so in the basement. It might just be the nature of things. I like the idea of potentially opening an outside air intake automatically only when the boiler fan comes on.
I'd like to add that most any time I open a window in the winter, cold air comes in. More so in the basement. It might just be the nature of things. I like the idea of potentially opening an outside air intake automatically only when the boiler fan comes on.
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That's my plan too (Currently we open a window in the boiler room when the boiler is lit, but inevitably it is some hours after it finishes the burn before we remember to close it again!). Just haven't got around to buying a mechanisation to open a flap of some sort. I was thinking of putting a round pipe in the wall with an iris-type shutter, but I'd appreciate any suggestions of suitable "mechanical flaps". The cross sectional area needs to be pretty big (sorry, can't remember how much off hand, but from memory it might be as much as 12" diameter)
I definitely don't want a flap that can open under negative pressure - wind blowing the wrong way will also push it open and cause draughts and heat loss. We are striving really hard to make the house more air tight, rather than less so, to conquer both discomfort (draughts, which then mean we feel cold, which then means we turn the thermostat up) and heat loss (through warm-air leakage). Main house is, from memory, around 2 - 3 ach (@ 50 pascals from memory), whereas the passive house extension is somewhere down around the 0.3 - 0.6 mark.
maple1
Minister of Fire
My solution for outside air intake was to leave a basement window that is right behind the boiler cracked open just a little bit, and put some fiberglass insulation in the crack. Air will flow through when there is a pull on it (or a push, like from the wind), but shouldn't under equal pressure situation (theoretical when not burning). I suspect it is going through all the time at least some - but not as much as if it were a wide open crack.
At some point I think it may be like squeezing a balloon. When a stove vent or bathroom vent are on, they are removing air and it must be replaced. I guess it is question of do you want to control where it comes in. No doubt the boiler is the biggest draw but as I think about back draft from my fireplace, air being pulled through the smallest weaknesses in the seals in my sliders I now have a much better understanding of why it is happening. Thinking if I can redirect all of that inbound air to my boiler room the rest of the house will remain more comfortable and potentially keep your thermostats from kicking on. Of course mine are always on but that is a sorry for another thread that I will start in the next few days - since you are in the UK and by looking at the sophistication of your system, I am thinking that you are far beyond my level of knowledge when it comes to leveraging a shunt valve to maximize the potential of your storage.
we are good for something once in awhileThanks, I think I learned that was my issue. My boiler was brand new so I underestimated the effect of those 1st dozen or so bad fires. When the boiler was manufactured they forgot to install a small impeller that cools my fan motor. Because of the position of the impeller I never knew one was supposed to be there. The manufacturer never had this problem before so they didn't think of it. They were great though. They sent countless hours on email and phone helping me diagnose. Sent me a replacement motor from Europe basically they did everything and anything to help. Luckily woodburners stick together and in a conversation with another Effecta user in Alaska I stumbled upon the impeller.
I am looking forward to switching from pellets to wood and compare notes
I am not sure how we would have figured it out without you - checking that impeller was not on anyone's radar! Definitely curious as to how you make out. Obviously you will need much hotter water than me so I am curious as to how much mixing stretches you out.
John and velvefoot, I'm not absolutely positive this is the one I purchased, it was a while ago, but try these links http://www.supplyhouse.com/Fantech-...draft-Damper?gclid=CM_30Oif5bMCFUQw4AodwSoA2w. Installation instructions, http://s3.supplyhouse.com/product_files/RSK6-install.pdf. I used a standard dryer vent cover with a mesh screen on the opening on the outside of the house. This is to minimize wind possibly holding the damper shut and the mesh to keep bugs from getting in.
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After going out to my boiler room and looking at the damper I realized I had chosen another model than the one I misremembered above. I went back and found my receipt for the damper I do have installed. It wasn't the Fantech model. It is the Continental Fan Manufacturing BDD150 Spring Loaded Backdraft Damper for 6" Ducting, purchased from Build.com.
The double doors seal quite well on a gasket. It opens when air needs to be pulled into the room to supply the boiler, and stays closed otherwise. The catalog says it requires from 0.04 to 0.08 inches wg pressure to open. How you'd measure that or know how many inches wg your boiler produces, I don't know. My Tarm Solo Innova has an induced draft with a powerful fan so it wasn't an issue.
Try this link: http://continentalfan.com/e-catalog/oem/bdd-backdraft-dampers/. The damper fits into a standard duct. This link to the Build.com site list lots of damper choices in addition to the above. (broken link removed)
Mike
The double doors seal quite well on a gasket. It opens when air needs to be pulled into the room to supply the boiler, and stays closed otherwise. The catalog says it requires from 0.04 to 0.08 inches wg pressure to open. How you'd measure that or know how many inches wg your boiler produces, I don't know. My Tarm Solo Innova has an induced draft with a powerful fan so it wasn't an issue.
Try this link: http://continentalfan.com/e-catalog/oem/bdd-backdraft-dampers/. The damper fits into a standard duct. This link to the Build.com site list lots of damper choices in addition to the above. (broken link removed)
Mike
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