Vedolux 37 air setting

[Coal Reaper]

what is recommended setting? finally starting to get tanks warm (just in time for the end of the heating season!) so i have been playing around with some fires. making adjustments to the air settings doesnt seem to change anything. i am burning 18-20% MC oak with 20-22% ash and maple. flame is really kicking ( i think? see pic, in actuality it is slightly more blue in color) and i am happy with it but i was just curious how everybody else manages air control. stack temp about 200-225C. 12' of 6" vertical class A. have all the turbs in. 55F water coming from storage, 160F water going back to storage. just got the temp gauge at the bottom of the tanks to jump to 135 last night. lot of water and steel to get warm. thanks!

 

[Floydian]

Congrats on the fire, Coal Reaper!

I have gone with the recommended settings as per the manual-secondary damper closed, tertiary damper (glass window) at 4 mm or about 3/16". This has worked well for me as I consistently get a light grey/brown colored ash that indicates a clean burn. The wood I burned had a MC of 17-20%.

Your flue temp seems a little on the high side for what I have seen. I am usually in the 175-200 range, higher if the tubes need cleaning. The only exception to this is when I burn a full load of smaller splits(too small), than I will see higher flue temps in the 200-225 range. No puffing whatsoever but the output of the boiler seems too large for the HX surface area with a full load small dry splits(Ash). When I say small I am talking splits with a cross section of 10-12 square inches. I had these small splits because I was a little behind on last years wood and re-split some 22-25% Ash in Nov. By Feb these small splits were 17-19% MC.

What speed are you running on the loading unit? I ran on speed 2 for a while and would see a supply temp of about 160(140 return) . Switched to speed 1 and I see 165+. The bottom of my storage is always around 90 when I fire the boiler except for that first fire with the tank at 58 . Seems happier with speed 1.

Noah

 

[maple1]

I'm not sure of the differences in adjustments & air settings between the 37 & natural draft units, but I THINK I've found mine burns more consistently better with the glass window pretty well closed. Then again, I've stared at that fire long & hard on several occasions while changing the window adjustment and not noticed a whole lot of difference in the burn. I do think if I'm on the edge of good gassing conditions, having the window open more will lead to the secondary burn being blown out easier - you can try that effect by popping the bottom window door right out or partially out in the middle of a burn & seeing what happens.

Congrats here too!

 

[Coal Reaper]

thanks! excited to finally be burning even though its just warming the tanks. i hope to make the connection to the system in the house this weekend.
currently i have the secondary halfway and the tertiary one full turn out. but it seams like no matter how i change those the output is the same. i will open tertiary more i guess. maybe thats why my glass isnt clean. my ash is light grey with just a hint of brown/tan. and all wood and coals gets burned 100%. i am thinking uf upping the fan shutoff temp slightly in order to leave a little coals to have upon relighting. i am very surprised how little ash there is for the amount of wood i put in, not that thats a lot either.
i have only cleaned the tubes once, after the second fire. there wasnt much of anything there. i will clean again before next fire and i know i should do a quick brushing before every fire. cross section is 10-12 on the ash and maple. 16-25 on the oak, but that are only 12" long pieces. i didnt cut those and i will be getting into 20" long birch soon that will let me pack the firebox more. most of my wood i think is about 16" cross section. i have a batch of oak 25" cross section or a little larger that is at 30% now and i hope its is ready in 6 months or so. before i found this forum i had it stacked on the north side of barn right up against the wall. this was about 16 months ago. now its in full sun and decent wind so we shall see. debating chopping them in half but dont feel like restacking again...
loading unit is at 1 and i was seeing 165 output with 55 water from storage being mixed in. now that bottom of storage is at 135 i am seeing 180 coming out of boiler. took 3 fires at 50% loaded firebox and one at 75% to get there! i need to get the x-300 wired in so i can see the temps at different levels. i have sensors for top and bottom of tanks as well as 1/4, 2/4, and 3/4. right now i am just reading dial gauges, one close to top and one close to bottom. picture here was after first fire.

 

[maple1]

I'm not sure - but I don't think you'll have much left for the next fire by shutting your fan down earlier. Maybe a few small dead coals. I get nothing but ashes when I go to light - everything burns up real good. There might be a fan/natural draft difference there though - with mine the draft slowly decreases as the fire slowly dies out.

 

[Coal Reaper]

maple, are you still using the fireplace grate on top of your ceramic? how did that go for you? i have thought about a sleeve in the nozzle to reduce wear. the coal that fall through for me dont last too long. with the fan cranking i wouldnt think it is hindering performance at all.
i am guessing shutting fan down at lower temp would eventually put fire out and should leave coals. manual states boiler will be running at 10% only 20 minutes after a power failure rather than continuing cruising along. the fan must give a decent amount of resistance. i will try slowly backing it off each burn and see what happens.

 

[Coal Reaper]

I have gone with the recommended settings as per the manual-secondary damper closed, tertiary damper (glass window) at 4 mm or about 3/16".

Noah

just pondering: what is the point of secondary damper if it is recommended to be closed?

 

[maple1]

maple, are you still using the fireplace grate on top of your ceramic? how did that go for you? i have thought about a sleeve in the nozzle to reduce wear. the coal that fall through for me dont last too long. with the fan cranking i wouldnt think it is hindering performance at all.
i am guessing shutting fan down at lower temp would eventually put fire out and should leave coals. manual states boiler will be running at 10% only 20 minutes after a power failure rather than continuing cruising along. the fan must give a decent amount of resistance. i will try slowly backing it off each burn and see what happens.

Yes I am. I think it helps maintain a hot coal bed up where the fuel is - especially helps on reload when you can just quickly pull whatever hot coals are in the firebox over the grate & load right up. Otherwise I get a big pile of coals right under the nozzle that eventually burns up but doesn't do a whole lot for helping to gas the fuel. There's not much left to it though - have it pretty well burned up.

And how about that - I have also thought about the sleeve thing for nozzle wear. Just not sure what you would make it out of. At one time I was thinking of something like a deep stainless frying pan or shallow pot the right size with the bottom cut out of it. But the hole isn't round, it's oblong (at least mine is) - if someone came up with something suitable, I'd likely be in for one. Maybe incorporate something grate-like into it too. Having said that, I have a crack in my top front refractory - it's been there for a while, right down the middle (front to back). Not sure how it happened - I must have gotten careless putting wood in at some point, either dropping it or jamming it. I'm not replacing it any time soon though, I just keep a layer of ash over it & it hasn't moved any.

 

[Floydian]

just pondering: what is the point of secondary damper if it is recommended to be closed?

I've wondered about this as well. Maybe an email to Dean is in order....

i have thought about a sleeve in the nozzle to reduce wear.

I am really not too worried about wear around the nozzle. Just looked at mine and it looks "new" after burning about 3 cords. The Varm's don't have the increased flame velocity through the nozzle that a lot of other gasser's have because of the larger round nozzle. Yeah, more coals can fall through but this hasn't been an issue for me. Even when this happens I still don't get any smoke out of the chimney. Another thing about the "lazier" gassification flame is this allows the use of the high temp SS combustion tunnel. I think this part wouldn't last long being blasted by the gassification flame that the long and narrow type of nozzle's create, thus the ceramic in the secondary chamber that is typical in most gassers.

I am more curious as to how the combustion tunnel is going to last. I am guessing I'll get at least a few more seasons out of it but who knows.....I am going to order a backup, just to have it.

Noah

 

[Coal Reaper]

yeha, i have yet to encounter a problem with coals blocking anything but i dont have much burning under my belt yet.
material type may not be too important if it is cheap to make. just replace it every year or whatever it takes. it has only been one season for you but what part of it do you see the most wear occurring? i think my nozzle is round. i will have to take a better look. i had done some research on the type of steel used in the channel. it is some crazy stuff from china that is commonly used in refractories. other stainless steels dont have as good abrasion resistance properties at high temps. i think this performed well to 2500 or 3000F. dont know about sourcing it.
did the ceramic crack before or after having the grate? idk what the bottom of you grate looks like but it may be concentrating the weight of the wood load to just a few spots (4 or 6 or how every many points of contact there is between grate and ceramic). without the grate the splits can distribute the weight more evenly. and more even mores so with a layer of ash acting as a dampener.

 

[Coal Reaper]

part of me wants to believe that they know what they are doing over there in sweden and to just leave well enough alone. the boiler as a whole seems so well built yet simple, one would think they have explored these avenues so why mess with it.
has anybody had to replace any of these components yet due to wear? have the varms been available long enough in the USA for us to even have seen this point yet? i recall dean stating that he started selling them 5 years ago and that these parts are typically good for 5-10 years. the answers to my questions may likely be NO, but ill throw them out there. this is the only brand of boiler he sells now so that has got to say something. i have only recently had my wood burning cherry popped, but my only issue so far is that i wish the firebox and door were a bit bigger. other than that this thing is very easy to light and starts gassing quickly and then gets the hot water moving shortly after. i feel i would be able to easily diagnose any problems i had as well.

 

[maple1]

I cut the feet right off the grate before I put it in. So it was a flat bottom, on top of a layer of ashes. If anything I think it would have protected the ceramics by spreading the load. As time went on it got smaller - burning into halves then quarters. I always made sure it had a good layer of ash under it, and if it got mishapen so load was being concentrated it was directed into the area right over the bottom bricks. Most of the time it was not very big and in the middle of an ash layer so there wasn't much weight being put on it at all. I think I must have gotten a stick in that had the end pushing down in the front middle of that ceramic, then that got subsequently squeezed down with further loading. As mentioned it is staying put for a long time - not a big crack, not moving, and covered by ash. Aside from that I have seen no sign of wear on the ceramic surfaces from the looking I've done - I've been through somewhere in the area of 5 - 6 cords so far.

EDIT: I got some spares when I got my boiler. They got pushed in under my basement steps before I then moved my expansion tank & hot water tank under there too. I THINK I can get them drug out when I need them.

 

[Coal Reaper]

Good deal.
Now i gotta ask why the need to even rake coals? Aside from smoothing out a big pile cant you just put in wood on top of coals no matter where they are?

 

[Coal Reaper]

Good deal.
Now i gotta ask why the need to even rake coals? Aside from smoothing out a big pile cant you just put in wood on top of coals no matter where they are?

 

[maple1]

Well, yes, I could - but if I don't pull the coals over the hole that means they're scattered around the edges. So the fire re-catches slower, and takes longer to get gassing good as there's no bed of coals that the gasses get pulled through right away. If I pull the coals in over the grate, then by the short time I reload & get the door shut & damper closed I've got a good gassing fire going. If I don't, it just takes a bit longer for it to get up to speed again. That effect might be amplified by the natural draft thing - with the fan you get instant draft with a button push.

EDIT: If I reloaded sooner, before the fire started burning down through & opening up the middle of the coal bed, that also wouldn't be an issue. I usually let it go a full 4 hours or so on a full load before reloading - at which time there's not much fire left.

 

[Coal Reaper]

gotchyah.
if you and noah dont have any wear around the nozzle then i am going to leave things the way they are for now. dont fix it if it aint broke. build it better when it does break.

 

[Clarkbug]

I've wondered about this as well. Maybe an email to Dean is in order....



I am really not too worried about wear around the nozzle. Just looked at mine and it looks "new" after burning about 3 cords. The Varm's don't have the increased flame velocity through the nozzle that a lot of other gasser's have because of the larger round nozzle. Yeah, more coals can fall through but this hasn't been an issue for me. Even when this happens I still don't get any smoke out of the chimney. Another thing about the "lazier" gassification flame is this allows the use of the high temp SS combustion tunnel. I think this part wouldn't last long being blasted by the gassification flame that the long and narrow type of nozzle's create, thus the ceramic in the secondary chamber that is typical in most gassers.

I am more curious as to how the combustion tunnel is going to last. I am guessing I'll get at least a few more seasons out of it but who knows.....I am going to order a backup, just to have it.

Noah

Just cleaned out my Varm for the season last weekend. Im finishing up my second season, and my combustion tunnel is showing it. The cross bar at the front is gone, and its starting to wear a notch in the front portion of it, right where the flame makes a u-turn to head to the back of the boiler. For reference, thats about 10 cords total.

So new tunnel will need to be ordered. Ceramic has a crack along it as well, but that was there at the end of last year, and hasnt been a problem at all.

Coal Reaper, I also adjust my shutdown temp dial. I start it for the season, or before I want to clean it out at 120 (the dot), but i did a trial and error thing to see when the boiler would stop adding heat to the tanks, and put a mark there. That way it shuts down, but leaves a decent amount of coals. Hit them with the torch the next day to re-light, and its good to go.

Also, you dont need to brush your tubes before every fire. I do mine once a week, and thats even overkill.

 

[Coal Reaper]

can you put up a picture of combustion tunnel?
i have the point on the dial aimed at the 0 in 120*. that leaves me just enough coal barely intact to place over the nozzle to get the next fire going. hit it with the torch or a small piece of paper or handful of noodles and we are off to the races immediately.
yeah, i am not going to worry about brushing more than once a week.
i only have maybe four 50% loads and another 4 loads at 75% firebox capacity through the boiler. still trying to get some time to finish connections to house. i am tied into the oil burner and valved off. aside from some electrical work all i need to do is run one more pex line across the barn and plug them all into the sharkbites. that thick of pex is a bear to run through small holes and along beams when all it wants to do is twist and curl back into a coil. soon, very soon...

 

[maple1]

Try to 'unroll' the pex (like it would come off a hose reel if it was on one), rather than take it off sideways. It's not easy to do & you'll likely need help - but the more you can unroll it the less it will try to recoil. It's still a bear to handle though, either way.

Clarkbug, can you lay/set a couple of thin firebricks over the wear spots for protection? I'm not quite sure where the wear is on yours though. I laid a thin one on its flat directly under my nozzle, thinking that was where most of the wear would be - but not sure if that would direct more of it up and/or to the sides. My cross bar is as new, but I think the 37 burn comes forward then bends to the back - whereas the 40/50 just goes straight back.

 

[Coal Reaper]

yeah, i put the whole coil on a dolly and spun it as i unrolled. i played the whole game of leaving it sit out in the sun in the driveway for a few days too. this is what it looked like when it first came off. i was by my lonesome when i had to set it in trench and pull through slab into barn the night before the foam guys were coming...

(broken image removed)

 

[Coal Reaper]

my crossbar gets red hot once everything is burning good. need to find a way to mitigate erosion there. 37 does come forward and then back after wrapping around the tunnel, but the flames slam that crossbar in the process. you can see it starting to glow in the original pic i posted.

 

[Clarkbug]

Ill get some pics of the tunnel later today, if I can remember in the course of my tinkering.

I wanted to say that my bar also got beat up since I used that as a point to "hook" it with the cleanout tool. Part of my daily routine is to pull the tunnel out, scrape any ashes out (leaving a layer on the very bottom), and then pushing it back in. Perhaps thats not the best way to do things, as it took its time on that bar, and I dont know that I really need to pull it out to scrape it. It just seemed easy to pull ashes into the drawer that way.

 

[Coal Reaper]

been taking wood fired showers since thursday! still working on getting all the air out of the system. i was scared the bumble bee circ was too small for the storage to house loop but it has been moving more water since i got most of the air out. once everything is warmed up it backs off on the speed just like it is supposed too. runs at 11 watts at that point and claims 6gm. hopefully the charging temps increase when i stop playing around with the pump speed on the loading unit. i have been cycling between 2 and 3 trying to move the air. it should be on 1.

 

[maple1]

We've been on wood fired showers since October. I've been finding some shortcomings in my setup though when doing solely DHW from boiler & storage - they were masked by the constant load demand & flows when heating. I'm slowly working my way through trying to sort them out as efficiently as I can and will try to start a new thread on that once I get things ironed out. Right now I'm still burning every second day just for DHW - I could likely extend that to every three days but I am staying in my 'safe zone' so I won't get the wrath of the others in the house if I should happen to accidentally let the DHW temps get too low. I think there is an Alpha in my future...

 

[Clarkbug]

Sorry for the delay! Lots of going on outside of Hearth now that has warmed up outside....