Sweet Spot-Gasification

rockwall

Member
Dec 1, 2015
22
Central Maine
Just wondering what others do with their gasification boilers with storage. I have a Tarm 30 with 820 gallons storage. I tend to charge the tank up to 175-185 and then when it gets down to 135 or so I start another fire and bring it back up. Where is your sweet spot?
 

Bad LP

Minister of Fire
Nov 28, 2014
951
Northern Maine
I was hitting mine again last weekend at 125-135.
 

Fred61

Minister of Fire
Nov 26, 2008
2,433
Southeastern Vt.
I had 500 gallons of storage and pretty much lit a fire every evening in the dead of winter. The tank temperature was usually about 140 after 24 hours. Several times I knew I could have gone another 24 hours if the weather was not too severe but if I was wrong nd the temperature dropped unexpectedly it would be hell to pay if my wife's shower was not steaming hot the next morning.

Fortunately it was not a huge chore to light up the EKO. I would shut down the boiler after reaching a tank temperature of 180 or so and always make sure There was enough charcoal in the firebox to light the next fire. I always kept a supply of charcoal on the side just in case it happened to burn out all the charcoal.

Placed whatever charcoal I had (usually a handful) over the nozzle, filled the firebox with splits. Ran the propane torch up through the nozzle from below for about 30 seconds then pulled the torch, started the fan, shut the bypass.and walked away.

I should tell you that this process was made even easier if you had a booster fan in your flue. I ended up with one because of ignorance just after installing my unit but found that it wasn't needed but I still used it for lighting the fire.
 

warno

Minister of Fire
Jan 3, 2015
1,236
illinois
I don't want to high jack your thread but I've always been curious how looking does it take you guys with gassers to raise your storage 40° like that? Curious about many gallons you have and how many hours it takes to charge up.
 

peakbagger

Minister of Fire
Jul 11, 2008
4,807
Northern NH
My time to raise the storage temp is not that far off from my boiler rating. I figure out how many Btus required by multiplying the delta T of the tank multiplied by the pounds of water in storage (roughly 8 pound per gallons and divide by the nameplate on the boiler. I add about a half hour to 1 hour for the initial warm up from a cold boiler. Its not a gasifier but the math is the same.
 

maple1

Minister of Fire
Sep 15, 2011
10,119
Nova Scotia
Just wondering what others do with their gasification boilers with storage. I have a Tarm 30 with 820 gallons storage. I tend to charge the tank up to 175-185 and then when it gets down to 135 or so I start another fire and bring it back up. Where is your sweet spot?
That depends a lot on the house & distribution system and what supply temps are needed to maintain house temp.

Lately here I have been letting it go down to 120 or so and charge until I have 180 or so. I have been trying to stretch time between burns though, with some mini-split use mixed in. But not a lot different than otherwise. I usually try to fully deplete, then burn until I get 2 laps through storage. The house usually has lost a bit of heat by then, so I am also recovering it at the same time. That keeps my boiler at 140 in/160 out for as long as possible, which I think is where the best efficiency to be gained is. Next lap is about 160/180. And doesn't take that long. Going the next lap would lose more heat up the pipe than I want to, IMO.
 

Fred61

Minister of Fire
Nov 26, 2008
2,433
Southeastern Vt.
I supplied my in floor radiant with 125 to 135 degree water only from storage. no fancy controls or valves.. If the thermostats were calling for heat during my recharge it would take up to 4 hours however late afternoon the house is still holding heat from solar gain.so three hours was the norm. Quality of the wood was a factor.
 

eauzonedan

Member
Jan 21, 2011
88
Bayfield Co. Wi
Not a black and white answer here but sorta similar. Shoot for 180 for storage top and the low number is driven by emitter needs. I have in-floor, Warmboard, optional flat panel rads as well as dhw. Need about 140 supply to make dhw so if somebody needs a shower and I don’t want the lp boiler to kick.... that’s the critical low number. The flat panels are in mostly in un-used spaces but they like the similar supply temp as dhw to make much heat (if they’re on). During the day I typically only need in-floor and Warmboard and about 110 supply makes those happy. The last piece of the puzzle is the storage tank temp and that becomes an issue do to stratification. Right now the bottom 1/3 is at 114. The middle 1/3 is at 139 and the top 1/3 third is at 170. Since I pull supply off the top (170) area - all emitter types are happy - even though the storage is under 140 (average temp). If I play my cards right and manage when I dump heat into the shop slab I can get by with a single burn lasting 2-3 hours down to Almost zero at night. Below that I just load wood am and pm which is about a 10 minute deal apice. System is a Garn 1500 (1500 gal storage) that is isolated from the emitters with a HX and a variable speed pump on the Garn side to make whatever temps the emitters want... short answer is bout 120 to 140 storage tank avg temp.
Dan (yikes just read this and I’m a nut case)
 

Woodman1

New Member
Jan 15, 2018
79
Michigan
40 degrees in my 1000 gallon storage takes about 3 hours with my eko 60. It is also heating the house at the same time though which pulls around 35k-50k btu/hour or so. I works out that I start my burn about the same time the house thermostat goes from 69-73 for the evening.
 

Marshy

Minister of Fire
Dec 29, 2016
820
NY
Takes me 3-4 hours to go from a top tank temp of 140/150 up to 180F. Largest variable is outside weather and the zone demands during recharge. I have 820 gal solartechnics tank and standard baseboard. I'm always looking to maintain a minimum of 140-150 top tank temp. My froling suggests 10kg of wood when my tank is at about 160F and as much as 16kg of wood when it down to 140F. Less than 130F it calculates 20kg or more. One thing I noticed is the output of my boiler doesnt seem to be the maximum rated (102 kbtu/hr) unless the firebox is fully loaded.
 
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TCaldwell

Minister of Fire
My design temp for outdoor reset is 143 at 0 degf, so I like to be above that at 5am. I’ll fire then usually between 60-90lbs, as it takes 3 lbs wood to raise the 2000gal garn tank 1 deg. As the sun comes up between solar gain and increased air temp the design temp drops, my next fire is usually 90 lbs between 5 and 8 pm to charge up for the overnight. This routine started about December 1, prior to that one burn a day was good, I run about 6-6300 degree days per year, about 33,000 btu per degree day or 7/8 cord per year
 

Marshy

Minister of Fire
Dec 29, 2016
820
NY
I just did a double check last night... my wife didnt do a fire in the morning so the tank was drawn all the way down to about 127F top tank temperature. The boiler called for 17kg of wood. I filled the firebox 3/4 full and away it went. I checked it in 3 hours and only thing left was a pile of coals in half the bottom of the firebox and then top tank temp was 173F. I threw two more splits in and let it run.
Outside conditions were about 25F, no winds so the zones weren't in very high demand as the house was still 68F and thermostats are set to 70 before I fired the boiler.
 

Adirondacker26

New Member
Aug 7, 2018
23
Adirondacks
Hi all. I’ve been looking around to find what my flue gas temps should be. Running a Froling S3 turbo 30. I keep finding different info on this and even contacted the dealer and they’ve told me yet another different range of temps that I can’t verify. I’ve been seeing 170 C or 338 F from web pages from Froling. Maybe someone else out there has found this info out for sure from a 100% trusted source. Best I can tell is that I should be seeing temps around 350F at nominal load. What I have is around 420F and some times up to 475F.
 

Adirondacker26

New Member
Aug 7, 2018
23
Adirondacks
Yes every 250 hours or so. Cleaned them this morning. Took about 12 minutes. I think my draft might be too high so I’m going to be propping my barometric damper open for a few burns and see what happens. I’m now 100% sure the temps should be 300-340 degrees F. Thats from Froling. Other than this flue temp thing, this boiler is doing a superior job. I just know I could get more efficient burns if the temps were in the range set by the manufacturer. What are your flue temps? Im burning hard maple and white ash with a moisture content of about 18% on the inside and about 12% on the outside so I’ve set the computer accordingly.
 

maple1

Minister of Fire
Sep 15, 2011
10,119
Nova Scotia
Yes every 250 hours or so. Cleaned them this morning. Took about 12 minutes. I think my draft might be too high so I’m going to be propping my barometric damper open for a few burns and see what happens. I’m now 100% sure the temps should be 300-340 degrees F. Thats from Froling. Other than this flue temp thing, this boiler is doing a superior job. I just know I could get more efficient burns if the temps were in the range set by the manufacturer. What are your flue temps? Im burning hard maple and white ash with a moisture content of about 18% on the inside and about 12% on the outside so I’ve set the computer accordingly.
Completely different boiler but I also usually am in that same range (300-340).

When burning steady I try to brush my tubes once a week, on Sunday. I guess that would be something like 50 hours of burning? Will be doing it in an hour or two, only takes 10 minutes or so. Pretty sure I don't have to do it that often, but it is a routine I got myself into that certainly can't hurt the overall heat recovery.
 

gfirkus

Member
Nov 28, 2014
59
central wisconsin
Completely different boiler but I also usually am in that same range (300-340).

When burning steady I try to brush my tubes once a week, on Sunday. I guess that would be something like 50 hours of burning? Will be doing it in an hour or two, only takes 10 minutes or so. Pretty sure I don't have to do it that often, but it is a routine I got myself into that certainly can't hurt the overall heat recovery.
With my Switzer according to controls.... fan runs wide open till 350, then slows down and at 360 primary air shuts down. Regulates back and forth till heat loads drops below 350 then slowly secondary air closes and primary increases until wood is burned up. It seems to run the best from 330 to 350.
 

jebatty

Minister of Fire
Jan 1, 2008
5,717
Northern MN
Tarm Solo Plus 40. I burn mostly very dry pine with small amounts of oak, birch, aspen and ash. At my current draft fan damper setting, and with freshly brushed tubes, sweet spot gasification is flue temp 390-420F. After several burns and before brushing again sweet spot is 410-450F. At the high end output is the full rated 140,000 btuh and even a little higher. At lower temps output falls. I prefer the higher output because it allows for faster loading of 1000 gal storage, which I often load to the185-194F range.
 
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Marshy

Minister of Fire
Dec 29, 2016
820
NY
Hi all. I’ve been looking around to find what my flue gas temps should be. Running a Froling S3 turbo 30. I keep finding different info on this and even contacted the dealer and they’ve told me yet another different range of temps that I can’t verify. I’ve been seeing 170 C or 338 F from web pages from Froling. Maybe someone else out there has found this info out for sure from a 100% trusted source. Best I can tell is that I should be seeing temps around 350F at nominal load. What I have is around 420F and some times up to 475F.
Have you checked your flue temperature set point in your controls? I wouldnt change it but it may give you some insight as to the numbers you are seeing. My flue temperature during peak operation is typically 350-400F. I dont recall the exact maximum flue temperature during operation but I recall seeing 425F. I can check my flue temp set point and let you know. My boiler is a FHG, the previous model to the S3.
 
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Karl_northwind

Minister of Fire
Feb 13, 2012
516
Central Wi.
Interesting, I don't have storage, burning a heatmaster G-200, and my flue temps run between 320 and 400 typically. the higher flue temps are when I'm really ripping, combustion chamber temps in the 1500-1800 F temps (thermocouples everywhere) glad to hear I'm running in the same area as a froeling.
 

Marshy

Minister of Fire
Dec 29, 2016
820
NY
Yes I would be interested to know what your set points are. The default on the S3 is 428 max temp and 428 desired work point. Still scratching my head here.
Can you remind me what your concern is again? Is your flue temp low or high?
 

Marshy

Minister of Fire
Dec 29, 2016
820
NY
Yes I would be interested to know what your set points are. The default on the S3 is 428 max temp and 428 desired work point. Still scratching my head here.
Minimum flue gas set point is 248F, maximum set point is 482F. Desired working point 374F.