Indoor gassers vs. Outdoor gassers

[Gearhead210]

Hello all,

I am on my 4th winter with my home built outdoor comventional boiler. Located in SE michigan, last winter I went through 32+ face cord of firewood (yes it was unusually cold as we all know, but still thats alot). House is propane forced air that I have a HX above to use existing duct work with the OWB. 1600 sq ft old farm house, moderate insulation and windows.

I am going to replace the old boiler with a gasser, even though im ultra proud of the home built job. Just too much for one person to cut 30 face cord and attempt to get it seasoned in time.

I am cconsidering an indoor boiler with storage, or get a Portage and main optimizer 250 or CB 1450 outdoor gasser.

For the indoor boilers, I keep getting drawn to the woodmaster flex fuel 30 model, or the EKO 25 model. Both would be sufficient I believe.

Do the indoor gassers require the system to be pressurized to work properly? My reason for asking is that basically every OWB is vented. Basically every indoor boiler is sealed with expansion tanks.

If I were to go with indoor boiler I would likely buy 2 brand new fuel oil tanks and insulate the piss out of them once coils were installed.

Seems like a wash for the price difference on the cost of the equipment up front, the savings would come for the indoor model with the lack of the $15 per foot underground pipe, plus the obvious efficiency gains over the outdoor boilers.

I am at the shopping around phase at this point, if I cant make my mind up on which way to go by next spring I'll likely attempt to convert my homebuilt boiler into a gasser.

Any and all thoughts are welcome, this is an amazing wealth of knowledge here. Wish I had a nickel for every hour spent reading forums here [emoji2]

Thanks
Richard

 

[dspoon19]

In my experience of burning wood both indoors and out I prefer outdoors. Unless you have a walk out basement or very easy access to basement I'd go outdoors. Weather you put indoor boiler outdoors in a shed/garage/out building or just put an outdoor boiler up is the question. Besides that it will come down to cost I think. I chose outdoor boiler over building something or putting in a garage. I think it's quicker, simpler, and "cleaner" install to put outdoor boiler up. I've seen the P&M optimizer run and talked to the owners, they are very stout units. Quality built and very efficient. If I'd of had the cash at the time I would have got the 250 you are looking at. I chose a conventional P&M model and I still love it. Between boiler and complete install I'm right around $6300, I couldn't have even bought half of the P&M 250 for that!

Been burning for a month now and only used about 3/4 of a cord of junk wood. Saving the Osage orange and shagbark for January!

 

[binfordw]

You could always build an outdoor Gasser!

 

[rkusek]

I've alway wondered how much cleaner an OWB would burn with storage and how much the efficiency would improve. It would be worth looking into converting it as well since you have the skills. Have you followed Binford's homemade gasser build?

 

[dspoon19]

I've alway wondered how much cleaner an OWB would burn with storage and how much the efficiency would improve. It would be worth looking into converting it as well since you have the skills. Have you followed Binford's homemade gasser build?

I have been wondering the same thing. I have access to 3 300 gallon rectangular utility tanks and was considering chaining them together and making a storage system in basement. I guess it couldn't hurt.

 

[Gearhead210]

I'll have to do a search on Binfords. I was thinking of doing a "mock up" gasser without the water jacket, then if I can control the air flow enough to gasify I would build a water jacket. It would be way easier to modify without an extra tank to cut apart lol.

 

[maple1]

I have been wondering the same thing. I have access to 3 300 gallon rectangular utility tanks and was considering chaining them together and making a storage system in basement. I guess it couldn't hurt.

The thing with batch burning with an OWB is that it would sit without a fire in it for some periods of time. So glycol would likely be a necessity.

And depending how you set up your storage - I would stay away from ordinary 'utility' tanks, and oil tanks. If it's an open system they will be very prone to rusting, if it's closed they will be prone to going 'boom'. There might even be some 'boom' potential with open ones if the boiler is very much higher than the tanks.

 

[Fred61]

I personally would never install an outdoor boiler regardless of how efficiently it burns. I would install an indoor gasser in an outbuilding, barn, shipping container or grain bin as long as they are insulated. I wouldn't want the wind robbing me of the valuable heat the unit produced. Concentrating my preferences, I would prefer an indoor unit in a barn, workshop or basement where the residual heat can be put to use. I have my unit in my basement and with proper operation and maintenance I do not experience smoke, dust or odor problems.

 

[Hydronics]

I personally would never install an outdoor boiler regardless of how efficiently it burns. I would install an indoor gasser in an outbuilding, barn, shipping container or grain bin as long as they are insulated. I wouldn't want the wind robbing me of the valuable heat the unit produced. Concentrating my preferences, I would prefer an indoor unit in a barn, workshop or basement where the residual heat can be put to use. I have my unit in my basement and with proper operation and maintenance I do not experience smoke, dust or odor problems.

I would have to agree. If you don't have an outbuilding to put an indoor gasser in build a shed for one, preferably with enough covered storage for a season's worth of wood. If you're willing to commit the money, in my mind the Garn is ideal.

 

[Gearhead210]

My wallet isn't deep enough to justify a $20,000 garn once all installed to save myself $2500 each yr in propane.

But looking at binford's build I think I know what i'm going to be doing..... I need to get a hold of that guy. Ive got the machines and time to build a gasser, id like to see how his runs. I have a feeling my welder will be getting a workout soon!

 

[maple1]

It doesn't have to be a Garn. Or $20,000. The Eko25 you mentioned above has a lot of happy users and is quite economical, I think. Just make sure you take as much into consideration as possible - like, say, the need for a new shop or outbuilding. Or how nice it would be to have one that was nice & toasty all winter.

Lots of variables for different situations - good luck whatever you decide.

 

[flyingcow]

My wallet isn't deep enough to justify a $20,000 garn once all installed to save myself $2500 each yr in propane.

But looking at binford's build I think I know what i'm going to be doing..... I need to get a hold of that guy. Ive got the machines and time to build a gasser, id like to see how his runs. I have a feeling my welder will be getting a workout soon!

Rock on...i wish i had this ability and ambition.

BYW.....It's always nice to build a boiler room with a flat screen tv and a frig.

 

[binfordw]

Feel free to pm me,

I've only been up and running for about 3 weeks now, but we have had some really unseasonable weather, and Ive been very satisfied so far.

I guess mine could be considered an "indoor" gasser, albeit a very large one, in an outdoor enclosure- so I guess it doesn't really fall prey to the hatred for true "OWB's"

If you have the tools, I'd go for it. As long as you build in some adjustability, you should have no major problems. Thats what sold me on the idea, As long as you get it somewhat close, it can be modified easily to work well later if needed. I needed to choke my blower air down a good bit to gassify, which was easily done. I also wonder a bit about my exhaust temps being too low, but thats more of a longevity concern I guess. ( did add a bypass in the rear access to help raise temps which I havent opened so far- I haven't noticed any issues/moisture from the temps yet?) At the money it saved me over buying, if I need to rebuild in 4-6 years, I'd happily do so. Heck I already want to make another lol.

@ Flyingcow, I hear you lol. I wound up with about 3x4' of space in my shed, which has a stool but not much room for tv! Temps hit 130+ in there, makes a nice cold weather resting spot!

 

[Gearhead210]

I'm thinking that about a 20x30 enclosure, with sofa,tv, fridge, card table would be about right. Nothing excessive though. HAHA. I wish

But binford you basically did, and documented what I already wanted to do. I REALLY like the P&M style fire tube HX, was debating adding such a HX to my conventional boiler, but quickly realized that the pipes would look like the rest of my firebox- 1/2" thick in creosote. So, seeing as I have a 36" Ø by 26" long piece of 3/8" wall structural steel tubing leftover from my conventional boiler build, I would say that would be about right size for a primary burn chamber. I think i'll tend to lean more towards a smaller primary chamber, with more room for water storage, but stay vented for the simplicity/security of it. I also have a bad feeling about running pex pipe at pressure. I will likely sacrifice my current boiler, remove the firebox, and plate the end to use it as water storage, should give me around 450-500 total for rough numbers.

Having never operated a gasser, do you have any issues with alot of smoke/sparks coming out of the door when loading wood? I would potentially be sacrificing one bay of a 2 car detached garage to use as my "enclosure", and with the excess space stack a decent pile of wood to be in there with it- just worried about stray sparks flying over and burning the whole operation down after I load the thing up. My current boiler is pretty bad for that, but with a 3ft diameter x 5ft deep firebox it kind of likes to go nuts when you give it that burst of fresh air (went way too big on firebox size when building that one).

How thick of steel did you use on this? I was thinking of sticking with 1/4" steel for everything, no thinner than 3/16" though. I liked the thicker metal for weldability, I welded everything on my old smoke dragon with a stick welder, only had 2 pin holes to burn back across to get good seal everywhere. I would have all sorts of extra leak opportunities building a gasser though.

Binford: On the thoughts of your Drinking hot water, I currently have a plate (I think 15) heat exchanger pre heating my water before it goes into my propane waterheater, and the only times I ever hear the propane fire is if we haven't used any hot water for 8-10+ hours. Otherwise normal use (only 2 people plus a baby live here) keeps enough water flowing through, and never has to fire the propane on an average day.

The cost to build one of these will drastically offset the INSANE cost of the underground piping, I have an attempt at homemade underground pipe currently in use and I'm pretty sure the insulationis saturated..........2-3 degrees loss over only 50 ft....... so that will be coming up when the boiler gets lifted out of there. Worked good first year, the ground was already froze so I couldn't bury it, and just left it on top of the ground. Snow would stick right to it and not melt so I know it started good, no heat loss then either. Something got it wet though.

I think all together I have about $2500 in my current boiler, so your rough cost of $4-4500 sounds spot on since there are far more controls, materials than I have. I also used every piece of old crap metal around that I could salvage and weld to, what a pain. Took way longer than it should have. Nice thing is I have many many parts that I can use for the next one off of the current one. I don't think that I can justify the debt of buying a new boiler, plus pipe, only in the name of SAVING money. Plus- I can justify the machines and tools in the shop to my wife better this way HAHA

If its ok I will likely use/copy alot of the ideas, it will most likely end up looking different until I make the water jacket, since i will have a round firebox (only because that's what I have laying around), but the principles will be the same. I will likely be private messaging you at some point once I get into things in detail.

In the mean time I have lots of things to do on SolidWorks drawing this thing up!

-Richard from SE Michigan

 

[flyingcow]

Bucket list........ go on a tour of these self made boilers and even of the ones that are store bought. Gassers and non gassers. Just because.

 

[binfordw]

Having never operated a gasser, do you have any issues with alot of smoke/sparks coming out of the door when loading wood?

How thick of steel did you use on this?

-Richard from SE Michigan

I do not notice any sparks at all from loading door. I do get smoke, but its really not excessive- depends a bit at what time of the load/burn you open it up I suppose. I do get sparks out of the secondary door if I leave it open very long. If its in a garage, adding the bypass I opted out of would help alot with loading door smoke I imagine.


I used 3/16" for firebox, 1/4" for the secondary, and for all doors/frames/hinges, etc., 14 ga tubing, and 11ga for the waterjacket.

I have a problem with "over-engineering", thicker is not always better from what I gathered. Too thick will interrupt proper heat transfer in my opinion.

 

[redmaple172]

I installed a Polar Furnace G2 outdoor gasifier this year. I had height issues in my basement that prohibited an indoor unit. It is an open system so you have to test/treat the water. It can be installed inside so I could build a shed around it or move into a garage later. I was impressed at how clean it burns. I like having the wood and fire outside and not having to maintain chimney 35' above ground.

 

[NE WOOD BURNER]

Have you considered a Kuuma FHA Furnace?

You are in the right place for great advice!

 

[woodsmaster]

It's so nice to be able to build a fire and do maintenance inside a building. after having a boiler in a shed I'd never go to an completely outside unit. Who wants to load, clean, maintain, etc.in the rain, snow and wind ?

 

[binfordw]

The cost to build one of these will drastically offset the INSANE cost of the underground piping, I have an attempt at homemade underground pipe currently in use and I'm pretty sure the insulationis saturated..........2-3 degrees loss over only 50 ft....... so that will be coming up when the boiler gets lifted out of there. Worked good first year, the ground was already froze so I couldn't bury it, and just left it on top of the ground. Snow would stick right to it and not melt so I know it started good, no heat loss then either. Something got it wet though.



-Richard from SE Michigan

Oh- I should add, A friend did "cheap" underground lines as well, but I feel did them very well. He trenched deep, and layed tile down, then gravel before the insulated tubing. Sounds like a darn good plan to me anyway.

I did go cheap on my tubing, but it isn't the end of the world. If things work out ok, I wouldn't mind getting ahold of a backhoe and doing things again with better tubing in a few years. Ofcourse, its always easiest to throw money at an issue, just not always the best solution.

 

[dspoon19]

It's so nice to be able to build a fire and do maintenance inside a building. after having a boiler in a shed I'd never go to an completely outside unit. Who wants to load, clean, maintain, etc.in the rain, snow and wind ?

I'd be in an outbuilding of some sort if it was practical for me at this point. In a Few years I will move the boiler into a room off the future barn. I agree loading in the elements is no fun.

I just can't do in the house. Only way into the basement is through the living room and dining room. If I had a walk out basement or a way into it without going through the house id be more apt to do that.

 

[Gasifier]

I do not believe you should use fuel oil tanks for storage. Either way, that be a no-no. Find an old propane tank, add required fittings, insulate it, and with your skills you can have a pressurized system. Best route in my opinion.