Help needed.....just can't seem to get it right.

[vtwoodheater]

I just can't seem to get consistent burns. I thought it was dialed in about a month ago. Unless I stand in front of the boiler all day and put 5-6 sticks in every two hours, it just doesn't work.
Honestly last year with less than ideal wood, it ran harder and hotter. My wood now is dry (2 years), and if I load it up, I end up with a 8" deep bed of coals up top and a weak gasification flame.
I have tried just about every combination of primary and secondary air openings, with varying fan speeds to match.
Couple of bad burns with no real heat production, and I have condensation pouring out of my chimney pipe.
I thought my flame was getting snuffed out by the gusty winds so I purchased a dwyer and actually measured the chimney draft, got that under control. I was seeing .12" WC without a hard breeze. So I installed a baro damper and figured that problem was under control.
However, I have never seen a flue temp of 350-400 degrees. The hottest I have ever measured is 225 at the collar on the back of the boiler. Even while burning like it should, ramping up to 190 with storage just about topped off I can put my hand on the chimney pipe 3 feet from the boiler.
My lower chamber is clean, I have cleaned the exchanger tubes twice this year just because, and no creosote in my chimney. I can make icicles hang off the top of my chimney pipe though.
Sorry for the long post, it's just that I know how this process is supposed to work, and I can only achieve it 30% of the time. About ready to pay someone to come up here and show me how it's done.

 

[hondaracer2oo4]

I know nothing about biomass 40s or what you have as far as storage goes but I do have a gasser and this is what I would be looking at.

I would first return all settings back to factory settings to give you a starting point.

Second I would decouple the boiler from your storage to eliminate a bad return temperature valve.

Third I would adjust my air settings once a coal bed was established to allow as little primary air to the primary box as possible. If you are burning down to coals quickly that means you are burning the wood up to fast(to much air up top). You want the coal bed to have enough air to keep the coals hot and breaking the firewood down into wood gas.

 

[woodsmaster]

I believe the 40 only has a fan on the back ? Sounds to me like it's not getting enough air. Try burning it a few minutes with the upper door cracked open a 1/2 inch or so and see what happens.

 

[woodsmaster]

I know nothing about biomass 40s or what you have as far as storage goes but I do have a gasser and this is what I would be looking at.

I would first return all settings back to factory settings to give you a starting point.

Second I would decouple the boiler from your storage to eliminate a bad return temperature valve.

Third I would adjust my air settings once a coal bed was established to allow as little primary air to the primary box as possible. If you are burning down to coals quickly that means you are burning the wood up to fast(to much air up top). You want the coal bed to have enough air to keep the coals hot and breaking the firewood down into wood gas.

If the flue temps are too low and it's not gassing good I doubt the wood is burning to fast ?

 

[Fred61]

This year's wood is obviously dryer thus it coals up quicker. Moisture content plays a big part regardless of where you are on the scale. The coals on higher moisture wood burn away faster than they can be replenished by the higher moisture split. With dryer wood, the coals are produced faster than they can be burned away and will build up.
If you think you will be consistently be burning 2+ year wood you should make larger splits which will give you an overall smaller surface area. If you are going to let it season for a shorter period causing a higher moisture content then you need to split it smaller. That would balance out the wood breakdown.
For now I would take the advice that Honda suggested and play with the air.

 

[vtwoodheater]

Thank you so much for the replies. The biomass 40 has one fan on the back. I am burning to 1000 gallons pressurized storage. I bought this boiler 2 years old used, I have no idea what the factory settings are. The 1/4" primary and 1/8" secondary have always seemed to work the best, no matter what type of wood. Just played around with fan speed last year.
I will be consistently burning 2 year old wood this season forward. Two years from now, I will be 4-5 years dry. Last year with wet wood I was splitting down smaller. I can get a bed of coals very quickly, any wood I put on top catches immediately, no hissing out the ends at all. I know it isn't the wood this year.
Having to use bigger pieces of wood to slow down the upper chamber makes sense. Most everything I have is playing card size or a little bigger, nothing over 5" diameter, no rounds.
The Danfoss valve being faulty makes sense to me also, just figured for the price it would work longer than a year? I will isolate that as a last resort, I am actually moving the install next year most likely so don't really want to do much piping work right now.
If I leave the upper door open, it roars down below like a jet engine as it should, but 3 minutes into it, smoke is pouring out the door and the pieces of wood three layers up from the nozzle are starting to catch.

Woodsmaster: what are your air settings at, burning to storage?

 

[maple1]

You should be able to check the Danfoss with a couple of simple temp measurements - I don't think I'd decouple from storage. A good IR gun is very good to keep around.

How are you measuring flue temps - or what with?

I'm not familiar with the Biomass - but are there any un-obvious air passages that could block over time?

 

[Bad LP]

I'm still in the learning process here so forgive the question if it sounds stupid...

What is the moisture level of the wood?

 

[hondaracer2oo4]

It sounds as if your balance of primary to secondary air is off to me. If you have to much air up top the fire can be burning like a conventional right side up fire consuming wood above the coal bed. Then when the flue gas gets to the secondary nozzle much of the smoke has already burned up/ not enough secondary air to ignite the wood gas making it's way through the nozzle. Can you just leave the upper door closed and open your lower secondary door and play with your air settings to get it to gas?

 

[vtwoodheater]

Flue temps I am guessing are a little higher than 225 degrees, but that is all I have seen right at the outlet of the boiler with an IR temp gun. After I pull the manometer probe out, I can touch it with my bare hands no problem.

As far as checking the Danfoss, I guess I would shoot the pipe headed back to the boiler after the mixing has occurred with the temp gun?
It seems like a Danfoss failure is what has happened. I might get a replacement 150 degree pellet coming anyway.

I can leave the upper door closed and adjust air settings. I am going to fool around with it tonight some more.

Honestly I stopped checking the wood with a moisture meter after the first couple of fires in October. I was splitting and reading anywhere from 9-13% Any oak that I have may be 15-18%, so I just throw a piece or two in with a load of good stuff. I have been doing the "knock together test" here and there.

I can attribute my "2 years split and stacked" to every single person on this forum that said that to someone else. Thank you for that. Never really knew what dry firewood was. LOL

BTW, thank you for the help so far.

 

[NateB]

The condensation is from the low stack temps. I would recommend going with the air settings from the factory. You should at least get some gassification. I also found that I get better performance if I close the valve more in the recirc loop after it gets hot.

 

[hondaracer2oo4]

what were you saying about the danfoss valve being bad? Try calling the company to get the factory air settings.

 

[NateB]

(broken link removed to http://www.newhorizonstore.com/Products/89-biomass-gasification-boiler.aspx)

Here is the link to the manuals. I can't see your signature. Are you working with storage?

 

[JP11]

just wondering.. does your danfoss have a 'throttling valve'

helps balance out resistance so you get good flow to storage.

but it sure sounds like you aren't getting the fire.. not your heat not coming out of the boiler.

JP

 

[NateB]

I think the question with the danfoss is if it is not keeping the return water temp up high enough.

 

[hondaracer2oo4]

I agree that is air feeding the fire is causing the problem.

 

[vtwoodheater]

So I think I ruled out the Danfoss valve.
I started to lean towards smaller pieces catching too quick and then too much fire up top. I have had a coal bed all day, so I stirred it up a little and loaded up an armful of the biggest splits I could find in my stack.
I fooled around with the cover open for about 45 minutes ended up with the primaries at 3/8" open and the secondary at 7/32"
Eventually got the tremendous roaring flame back, and am charging my tanks again. Pump launch at 170, 15-58 on speed 2 and as of 5 minutes ago boiler temp at 176. Still have flue gas condensation dripping, but not as bad as before.
Thank you for the ideas, I will keep you posted.

 

[hondaracer2oo4]

How big are your splits again? Playing card size you said? So probably 3 inches? That is really small for me at least. I throw a couple that size down on the coal bed when I reload and then a few mixed into the wood load among the larger pieces. I would say on average my wood is 6 inch splits. Hopefully you have larger splits in your wood pile further out? You may be able to slow down the burn rate if you don't have larger splits by mixing less seasoned wood with the seasoned wood.

 

[vtwoodheater]

Yeah, everything is pretty much playing card size. Everything I have read here for the last two years seemed to suggest that. I do have bigger splits, but nothing over 5-6".
My firewood loads are mainly 50% maple, 35% ash, birch, etc. If I get any cherry or oak its few and far between.

The "fine tuning Biomass" sticky got me through last year. I still don't know what the factory settings are. Even the paperwork that I got with the boiler didn't have any pictures, measurements of air settings, or ideal fan speed settings.

Can the burn rate be slowed by fan speed only? Or does this just mess up the air settings?

This is kind of like tuning a carburetor, except instead of a quick ride to test and readjust, you have to wait 4-6 hours and evaluate.

 

[hondaracer2oo4]

Nate b posted a link where the owners manual is. The manual shows the factory air setting. I don't know about changing air speed. I would call factory and talk to them about it. Your split sizes may be fine as long as you are not burning wood above the layer of wood sitting on the coal bed.

 

[hondaracer2oo4]

How did today's burn go?

 

[vtwoodheater]

Well I messed around with it for a while in between loading the sander, moving some snow, and reloading the woodrack. Probably fiddled with the air settings a half a dozen times, threw in 3 arm fulls of wood.
Was able to maintain a pretty good fire all day, brought my tanks up to 187 top, 179 bottom. Boiler was at 180-188 most of the day.
I tried something different also. I turned my load circulator to run on low speed all the time instead of only coming on when a zone called for heat. Seemed to work OK, didn't shock the system with a huge blast of demand.

Although I seem to still be having an issue with the fire eventually burning up top and losing the gasification flame. If I open the smoke bypass and upper door to clear the smoke, then pull the handle closed and shut the door, it takes right off again for however long it takes to happen again.
Does this mean too much primary air, or not enough?

 

[Fred61]

Well I messed around with it for a while in between loading the sander, moving some snow, and reloading the woodrack. Probably fiddled with the air settings a half a dozen times, threw in 3 arm fulls of wood.
Was able to maintain a pretty good fire all day, brought my tanks up to 187 top, 179 bottom. Boiler was at 180-188 most of the day.
I tried something different also. I turned my load circulator to run on low speed all the time instead of only coming on when a zone called for heat. Seemed to work OK, didn't shock the system with a huge blast of demand.

Although I seem to still be having an issue with the fire eventually burning up top and losing the gasification flame. If I open the smoke bypass and upper door to clear the smoke, then pull the handle closed and shut the door, it takes right off again for however long it takes to happen again.
Does this mean too much primary air, or not enough?

I don't recall all of what was said above but that sounds like restricted draft like your fire tubes, etc.

 

[hondaracer2oo4]

I still think your getting to much primary air causing a right side up fire.

 

[Fred61]

I think it's the draft or lack thereof.