Direct connect combustion air - Wood Gun E100

[muncybob]

Ponty, once you get all the leaks discovered and corrected I think you'll be a happy camper. Up until recently AHS had those rubbery silicone seals on all doors and mine looked like your pic after the 1st season too. For some reason the rope door gaskets I installed smeared with a generous coating of high temp silicone have held up nicely even though I know the silicone is only rated to 600(I think).

I do run with the damper about 3/4 closed and this along with larger splits as Mike stated have helped a lot with the huffing. I think a byproduct of mostly closed damper is more ash accumulation in my horiziontal pipe run to the chimney. I check this monthly and clean as needed.

 

[Pontypool]

Thanks Mike - I am going to apply the logic from Muncybob (above) regarding the back door so that tray will probably be staying pretty clean.

What I am calling a "filter zone" is a zone or loop off of my main loop that has is own circulator (Grundfos 15-58)and a stainless filter (see pic). All this zone does (when manually switched on) is filter the boiler fluid - mine is propelene glycol. I have been trying to educate myself a bit about the fluid - I am gathering it is pretty important to maintain the fluid in proper condition as it will silently destroy your equipment from the inside if it becomes acidic or there is too much particle.

Currently the filter zone only cleans the fluid. I was thinking to take, lets say, 50 feet of 5/8 inch flexible copper tubing and wrapping it around and around the body of the cyclone, and around the single wall vertical stove pipe (just like your pipe) attched to the cyclone. So the filter zone would now take fluid from the main loop, filter it, then pass it through the tubing which is wrapped around the cyclone, heating it and capturing wasted heat going up the chimney, then returning that filtered, heated fluid to the main loop. I would put a bulb with capillary aquastat onto the copper tubing right on the cyclone so that when it was heated to say, 190F the zone pump would start and very slowly move fluid through that loop, heating and filtering the fluid. As a by-product it would cause fluid to run through the filter regularly, right now I just randomly run the filter zone pump. The main idea is that you are getting more heat from your wood because you are capturing heat which is going up the chimney. My cheap magnetic stove pipe temp gauge says my cyclone heats up to 340F - Muncybob has a proper probe temp gauge and is measuring 380 - 400F.

I had an experience with huffing last night. I loaded the boiler with stump cuts & irregular knotty pieces - so lots of good solid dry wood which does not stack together, lots of air space in between pieces. It was a good hot fire & started huffing - even closing the damper didn't help. So I am understanding what you are saying now. My pieces are generally fairly large. I don't split anything less than 10" round. Splits from the body of the tree are generally at least 8 x 8. All my wood is Hickory - 24 inches long.

Currently my heat loads are a 32" X 28" - 4 row coil in the ductwork which is the main heating for the house, some zoned baseboards and DHW - will be adding the garage (26K BTU fan coil) hopefully this season. My wife likes the house to be 25 C (77F) - E100 has no problem with this.
Our house temp flucuates alot though. At bedtime, I set the main coil down to 21 C (70F) for better sleeping, then back up to 77F when we get up. If we are both going to be out of the house we allow the house to fully warm up, let the WG complete a cycle and normally shutdown at 190F then cut the power (2 switches) to the WG and all the circulators. We can be away for 10 hours, when we return the house will be about 68-70F and the WG will be about 130-145F. The WG fires easy from that temp and heating the house this way works fine for us.
I had a forced air wood furnace for 20 years before the WG - we ran it the same way - never an issue. I will not trust a wood burner to be left alone. I can live with the possibility of minor huffing if I am home, but will never allow the WG to run by itself when no one is home - call me paranoid. If it wasn't in my basement it would be different.

 

[Pontypool]

Ooops - forgot the pic of the filter zone - red pump on lower right and the stainless cannister. The copper lines come from the main loop down to the Grundfos 15-58, then to the filter cartridge, thru a flow gauge, ball valve (green handle visible) does a 180 degree turn back toward the pump then elbows up at the pump and returns to the main loop.

 

[avc8130]

Yes, I have one circulator pump and 5 zone valves. Any time a zone calls for heat, the pump is triggered and runs as well as that zone valve opens. When no zones call for heat, the pump is not running and all zone valves are closed.

I like your tray fabrication. I NEVER open my rear door.

ac

 

[Pontypool]

MORE seal leaks............. last night I noticed the large thick round steel plate which covers where the oil/gas burner would attach is oozing brown stinky stuff. There is a 1/2 inch thick white (something like compressed Roxul insulation) seal between the mounting surface and the plate. I noticed it was kind of browning last weekend when I was trying to solve my stink problem, so I carefully smeared 2 coats of high temp silicone from the mounting surface, across the seal to the cover plate all the way around. This morning I noticed there are jelly like bubbles of brown smoke (not really creosote) smelling stuff oozing out where the silicone meets the cover plate. If you burst the bubble it is full of brown stinky liquid. Should have taken a pic. Anyone seen this before???????

I have reduced the stinky smell to the boiler room while the forced air heating is running, after I smeared silicone around the fan motor mount plate, but have not been able to completely eliminate the smell. Yesterday after the system was off for 8 hours (but still at 140F) I came in the house to a strong smoky/creosote smell. I accept with any wood burning you will always have some smoke release in the house, but the house should not stink.

I checked my ash pan last night, nice fluffy super fine powder in there, no creosote. Checked the SS chimney liner, a light grey powder film, no creosote; checked the horizontal run to the chimney - some powder, some small chunks of charcoal - no creosote; checked the refractory tubes - powder & some charcoal - no creosote.
Muncybob - I am finding the same in my horizontal run to chimney (about 10 feet) getting some ash and some 1/4" to 3/8" charcoal bits.

I have adopted your method Muncybob & AC of absolute minimal rear door opening. I will clean tubes from the front (did this last night - first cleaning) and as long as I can see the rear door looking through each tube from the front, no reason to open rear door. Should help protect gaskets also.

I am thinking it is probably beneficial to leave a thin layer of ash in the larger refractory tube right under the center bricks to protect the refractory from the direct blast of the flame - does this make sense? Does anyone do this?

Ac - have you had any issues with zone valves (sticking, failure, short life, noise)? I want to use these also for small heating zones, wondering what to expect.

Pic of my woodpile - split size. Rack sections are 4 x 8, front is just over 7 feet high, pieces are cut to 23 1/2". With my old forced air wood burner I would use 3 1/2 of the 5 sections per year.

 

[muncybob]

Don't know what to tell you about the oil plate since I have the oil burner attached. There is a plug you can put into the front of the boiler for the oil "hole", not sure if that will help. When I had the oil burner off for cleaning I inspected inside the boiler oil area and it was cleaner than I expected to see...hardly any residue and certainly nothing wet.
When I clean the tubes I take out as much as possible with the tool. I don't see why leaving a small layer of ash would be a problem though.
Since you are getting small bits in the horizintal pipe run you want to watch the nozzle wear closely. A few years ago I tried to stretch my nozzle another season and because of that I wound up with some hot stuff in the pipe that had a small fire going. I now replace the nozzle every other year and this summer will have a SS plate fabricated to put on top of the AHS nozzle to perhaps get me another year.

 

[Pontypool]

When you say nozzle - are you refering to the slots in the center brick?

I am always hearing small pieces of charcoal bouncing around in the cyclone and maybe the 30 inch vertical pipe running out of the cyclone - I assumed this was normal.

Whenever I check the fire or add wood, I gently rake the sloped edges of the refractory to direct the coals toward the center brick - like it says in the manual - some smaller pieces fall through. Should I not be doing this?

I read some earlier posts where people had said they made 1 inch thick steel center bricks or another had used cast iron - can't find any later posts to see how that has held up. So you are buying replacement center bricks from AHS?

I am thinking that if this is going to be an ongoing (expensive) thing, to make up some steel bricks but with wings (or shoulders if you like) that would not only sit on the shelf but also on the top of the refractory, about 1 inch on each side to better distribute weight - would also protect the edges of the center trough. I had read in those posts about possible damage to the shelf. I am thinking if they were steel, if they wear I can always mig weld some patches on the steel. I have a small mig welder, but I am not schooled in welding. I am not good at welding, but I have become very good at grinding.

 

[Fred61]

I experienced that terrible creosote smell with my Wood Gun and found the biggest contributor to the odor was the combustion air intake box. The combustion air does not get preheated and causes creosote to condense on the motorized damper and drips into the box creating a puddle of the nasty stuff which smelled up the whole house. With my EKO the combustion air is preheated by having the air duct within the boiler. Snap open the box and look for a puddle of ooze.

 

[Pontypool]

Thank you for that Fred61 - that never occurred to me, have not looked in there. Will check that out tonight.

 

[avc8130]

I run the plug in my oil hole.

No problems with zone valves here (I hope I didn't just jinx myself). *knock on wood*

Honestly, I can't remember the last time I actually CLEANED my lower area. I check it, but the side tubes are always just about empty and the middle barely has anything on the bottom. Most of the time I see coaled wood that made it through the nozzle in there. I leave it and figure it burns to ash and then flies out through the tubes. You do NOT want ash in the refractory. You don't want to insulate the refractory. You want it to get as absolutely hot as possible.

I do collect A LOT of ash in the bottom of my masonry chimney. My flue run goes up from the cyclone ~4', then over 2' horizontal and then connects to a standard masonry chimney. I have a cleanout door at the bottom of my masonry chimney, and I collect ash in that like a second cyclone.

I don't think you are gassifying well. What are your flue temps? I have a feeling your method of operating the boiler isn't making a coal bed and you are really just "burning" the wood rather than gassifying. This creates a lower flue temp than designed and you are condensing your flue gases in the boiler trying to heat the water.

I'm in my 3rd winter on my original bricks. 20+ cord through. Honestly, they barely look worn.

ac

 

[maple1]

I accept with any wood burning you will always have some smoke release in the house, but the house should not stink.

Not all wood burning units release smoke into the house. The only time I get any smoke release at all is if I forget to open the bypass damper before opening my door, and even then it doesn't release smoke every time I do forget.

 

[muncybob]

Our nozzle is the center brick with the slots. About 16 cords is my absolute limit but I'm probably changing it out sooner than that just to be safe. When I do change it I will always do it in the off season, much easier with a cold boiler. I've read some people having decent results with 1/4" stainless overlays. When I get my next set of nozzle bricks I'll have one made.

We have no odor at all in the house and only a faint smoky odor in basement where the boiler resides. I could not say this until I finally got all my leaks sealed. The exhaust hood above the loading door also helped.

 

[Pontypool]

I am going to have a look at my nozzle bricks before I fire up tonight.

I am sure you are right that my method is not ideal - no arguement there. I seen one of InfinityMike's videos where basically the coals filled the entire refractory sloped area to where the metal walls become visible. I never have that much coals - usually only a couple inches to the sides of the center brick - so I should have the center brick covered in 4 or 5 inches of coals all the time? I have been going according to the manual and the advice of Mike Purnell that there should not be any real accumulation of coals, that the heat from the refractory is supposed to "cook" the wood to provide the gases to drive gassification. I do find the unit has a much louder "roar" when the unit is up to temp and the wood being burned is on top of a thicker bed of coals.

Last night when I cleaned the tubes there was very little in the side tubes and about an inch for about a foot in the center tube, coals mixed with ash.

When lighting I use Mikes method of holding a propane torch to the black coals - usually takes about 30 seconds to have a bed of red coals and kindling burning well. My cheap magnetic stove pipe thermometer says about 340F.
I bought an infrared temperature reader today - will be checking actual cyclone temp tonight.

Sounds like you (Muncybob) had basically the same issues I am having smoke/stink. You start with the obvious - the doors - once those are sealed you look at the other holes (oil flange, fan motor-2 seals, cyclone -2 seals, ash bin, smoke pipe, fresh air-Fred61).

 

[infinitymike]

Your splits look to be a good size for the WG, and based on that picture, it looks like the side wall of a 2 story house and not a 1 room apartment you are heating, I am still blown away that you can keep the house at 77* and only use 5-6 pieces of wood a day and are about 500 miles north of me. How many sq ft is that? It must be super insulated.

I am heating a 1951 house that has 720 sf of heated finished basement, 1500 sf of 1st fl and 500 sf of 2nd fl.
Yes it is poorly insulated, especially the first floor attic. I keep the 1st fl at 70* during the day (5:30am-11:30 pm) and set it back to 67* over night, I keep the 2nd fl at 70* from 5:30 am-8am then set it back to 67* until 9pm when it bumps back to 70 untill 11:30 when it sets back to 67*.
Last night it was around 7* outside and I loaded the WG to the top with large splits (7x7, 8x8) at 10pm at 6am it was empty, had a thin layer of red coals and was at 150*. I loaded it about 3/4 of the way with smaller splits 3x3, 4x4, 4x5 at 11am it was empty and at 160*, I filled it 3/4 of the way again and at 4pm it had a good bed of coals and some bones of the splits left.
This thing is eating wood like a termite on steroids.

So I say all that to once again say I am blown away with your fuel consumption.

 

[infinitymike]

To address the bed of coals.

Its best to keep the refractory as hot as possible which will occur with a good bed of coals. There is a thin line where to many coals, probably the amount in my video, that will cause a problem with getting air down into the gasifaction tube. But too thin a layer and "cooking" the wood becomes harder.

I think I have found the balance of when to reload so as not to have to many or to little coals. But, for me its not always that easy.
Also be careful NOT to let to much ash collect on top of the refractory inside the fire box.
It will insulate the refractory, which will reduce its temps and also I have noticed it clumps together and almost forms a concrete layer that can clog the nozzles.

 

[Fred61]

Mike's post made me go back and look at your woodpile. Those splits are big and you stack wood like machine. Looks like you squeeze 1.5 cords in a 128 cu ft. space. Are you sure it is able to dry when stacked so dense. If your wood is too wet that could affect the coaling rate of the splits.

 

[infinitymike]

you stack wood like machine.

Yeah, its perfect. pretty nice looking

 

[avc8130]

Mike's post made me go back and look at your woodpile. Those splits are big and you stack wood like machine. Looks like you squeeze 1.5 cords in a 128 cu ft. space. Are you sure it is able to dry when stacked so dense. If your wood is too wet that could affect the coaling rate of the splits.

Could also be his source of all that moisture...

ac

 

[Pontypool]

Sorry guys, the house in the pic is my neighbours house. I'll post a pic of mine from the back - to show the sunroom which looses MORE heat than the entire second floor (based on 2 different professional heat loss analysis).

Front part ground floor of my house built in June 1900, back - main floor 1974, second storey 1998, sunroom 2008.
Rectangle footprint about 1100 sq ft, so above ground about 2400 sq ft (there is also a small room off the front) plus we heat the entire uninsulated basement. I have renovated and properly insulated most of the house.
It has been -11F last few days - did not really change heat demand much, maybe one extra full size split and a 4 inch round.
Standard day for me - load 2 splits in the morning with what is left from the night (usually a full, charred split). Re-load around 6 pm - usually 3 more splits with a charred split, then usually 1 split around midnight. I always have fairly intact charred pieces when re-loading, never burned right down.

So I have this cool temp gun ($30) and I'm measuring everything. Last night I got home after a 9 hour shutdown.
Boiler wall 135F, refractory 210F. Attached some pics from cold and refiring. About 5 minutes into the re-fire I took multiple readings with the red dot on the center brick hole - getting 1047 F then the gun goes crazy because temps are over its maximum. Also determined my AHS supplied boiler temp gauge is 10F low, my cheap magnetic thermometer is quite accurate from multiple readings - my cyclone temps stand - never go over 340F according to the gun.

That wood pile is basically 2 seasons burning and is always filled - we put the seasons wood in the basement in October, then refill the rack. So one year I take from the front, next from the back - all my wood is seasoned a full 2 years (2 winters) and it sits in the basement where it is dry. Definately sure my wood is dry & properly seasoned - moisture meter consistently reads 14 - 19 %. Ha ha - if you like that wood pile I should include a pic of the one in the basement - it is like artwork - next week - hahahahaha.

So this morning I go to check the WG, it is cycled off, so I use the purge timer - only the second time I have used it.
Crank it to 15, green light, rake, load 2 splits and a tiny round - there was one charred 6x6 split left from last night, close door, go out to shovel the 6 inches of snow we got last night. Come back in 40 minutes later, check WG - OMG TEMP IS 223F ----- WTF???? Does the purge timer over ride the operating limit (set at 190F)? My high limit is set for 210F. Had to burn my underwear. And this happened with the main fan coil on and a baseboard zone. Can anyone splain that? Not intending to sound like a broken record, but this is why I will not leave it running while I am not home - just too many random events. Also had another medium explosion last night, WG cycled on after cycling off 20 minutes earlier under full fan coil load - thats the second time - running out of underwear.

 

[Fred61]

Where's the center plug? I assume you just removed it to take the photo and replaced it when the photo shoot was over. I hope! It's always a good Idea to run the tip of your chainsaw down the length of any round that you do not expect to split. That scratch will cut the drying time of the unsplit piece in half.

 

[Pontypool]

Fred61 -"I experienced that terrible creosote smell with my Wood Gun and found the biggest contributor to the odor was the combustion air intake box. The combustion air does not get preheated and causes creosote to condense on the motorized damper and drips into the box creating a puddle of the nasty stuff which smelled up the whole house. With my EKO the combustion air is preheated by having the air duct within the boiler. Snap open the box and look for a puddle of ooze. "

I am attaching a pic of my fresh air box from last night - it is not too bad I think.

 

[Pontypool]

Yes the plug was just removed for the pic, never run without it.

 

[Fred61]

I am attaching a pic of my fresh air box from last night - it is not too bad I think.

That's clean. So I guess you can keep searching. If I come up with any other thoughts I'll post.

 

[muncybob]

My limit is also 190, but I have seen it creep up high enough that I cannot restart manually until there is a call and the temp lowers. Did your purge timer go down to zero? I find that I have to be sure it is actually "ticking". I'm surprised you had a backfire after being down 20 minutes, I can go about 12 minutes on a short cycle and be fine.

Your oil tube has a lot more accumulation than I ever got. The plug or some other way to seal that may be a good idea for you.

Door seals and pipe seams must be completely sealed to avoid the smell. This includes the seal around the ash pan. This year I had my pipe seams welded so I can pull the horizontal run for a mid season chimney cleaning and not worry about opening up a silicone seal (mid season cleaning is probably overkill but it 's easy and fairly quick). It seems to have helped me I guess since as I stated previously I have no smell in the house and just a faint smoky smell in the basement.

 

[muncybob]

One other thing I forgot to mention, if you are using an infared gun to read temps on SS or reflective pipes it will not be accurate.