Outside Wood boiler

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Hearthyposter

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Aug 21, 2015
11
New York
Hey everyone I'm new to this topic and am thinking of installing an outside wood boiler. What steps do I take to go about this? Are there any specific requirements? Any and all opinions are appreciated!
 
There is a big difference between a more traditional and very inefficient, water jacket based, OWB and a very efficient wood gasification boiler installed in a small outdoor building. If the former, big mistake; if the latter, keep reading the various posts in this forum and you will find answers to all of your questions.
 
Jebatty, what about the Heatmaster G series 100 and 200 owb models? They out performed the Garn 2000 and 1500 in efficiency, emissions levels and rates.
 
Note my comment stated "traditional and very inefficient, water jacket based, OWB." I have no experience with the Heatmaster and cannot comment.
 
Ohh, I missed the spot where you said gassification owb, I just saw gassification boiler installed in a small out building(indoor gassification boiler)
 
Couple things to look at;

Check your local zoning laws, closest neighbors with allergies,
closest neighbors, building permits, prevailing winds,
very low efficiency, feeding times late at night/early in the morning
digging out wood pile from under snow. wet wood, very wet wood.

You may have neighbors that will not like a forest eater and may
take you to court once you start burning.

Dont forget your forest eater will spend a lot of time idling and making smoke.

For the money you should:

look at a coal stoker for the money, you could buy a small coal stoker boiler
and a wazoo load of coal OR wood chip burners Or a Garn Junior if you have
place to park it.
 
Leon sure does like his coal......
definitely look for something that is a gassier (starting with the EPA list is a good place to START) the "forest eater" is a conventional OWB which will do the smoking and idling, piss off the neighbors and eat a ton of wood (smoke is fuel you aren't using) In new york you may be required to use EPA certified stoves.

we can offer some assistance if you can tell us what size and type of house, heating system, and wood supply you have.

I have dealt with both the GARN and the Heatmaster G series boilers and they're both quality and efficiency. The GARN excels in simplicity, bombproofness, long track record and low/mid temperature applications. the G series has cost, continual high temperature supply temperatures, indoor/outdoor applications on it's side. I sell both of them with no reservations.

There are plenty of other options as well. and searching around here will reveal them.
 
I live in a 1500 sq foot house in upstate new york by the palisades. Im pretty sure I can install one, and am only considering this due to last winters cold. My central heating system is burning way too much electricity for my liking. My neighbors are a pretty good distance away and therefore they are not a factor. I Think the wood is pine and oak in my area. Thanks for all the help everybody!
 
is your existing electric system a forced air furnace sort of thing or electric baseboard radiators?
having to add a distribution system will add substantially to the cost. if you can just add a radiator coil in the furnace duct that will be the easiest.
 
You should be able to find answers to the original questions at a local dealer. There are lots of site & situation specific variables that would come into play.

That said, some don't get the best advice from their local OWB dealer - so take what he says & then research the heck out of it.
 
I'd want to be more than "pretty sure" I can install one of these before I planked down 10 to 15 thousand buckerinos on a new boiler setup. Any of the newer gasser style boilers need dry wood, if you don't already have a years supply put up, you're probably s.o.l. for the coming winter. You really need to start at your local building dept. first to see what is allowed & what isn't. Then too, your homeowners insurance may have issues with whatever you do. People have been forced to remove these units. Huge loss of money.
 
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I had a chance today to see a G200 at the MN State Fair but no opportunity to talk with the rep. The G200 has 1" supply/return nipples. This might lead a user to infer that 1" tubing/piping is adequate for this boiler. At a rated output of 205kBtu, 1" would be very undersized in most applications. Careful planning will be needed when determining the plumbing for this boiler.

The G200 has turbulators which by means of a lever to move them up and down are intended to keep the vertical firetubes clean. Other boilers have similar design. The problem is that if the firetubes ever have creosote buildup, and this easily could happen if wet wood is burned or the boiler is operated improperly by a new user, or if a burning mistake is made, I did not see a way to manually clean the tubes. The roof structure over the G200 did not appear to have an access to allow manual cleaning. This feature too will need careful attention.
 
You must have missed the cover on top of the g200 that easily removes to access the heat exchange tubes. It is suggested that you check them a couple times per season. If you need to you can sweep them easily. As far as th ports go, you can easily just put a 1- 1 1/4 adapter on it and run 1 1/4 from there on out , a small restriction on the suction side of the pump. The unit has been thoroughly tested by the epa. You can get all of the results right on the heatmaster website.
 
also if you read the install manual, system design is covered, including boiler flow rates, and the possible need for a primary/mixing loop on the back of the boiler to get 13 GPM thru the stove.

The top/rear access has to be a compromise of sorts. the old iteration had only access thru the top. on a 7' tall boiler, that's a hard/risky thing in the winter outdoor. the rear cover is super easy/convenient, but if you creosote up the tubes, cleaning isn't easy. there is still a top access port, but it involves removing the top of the stove to access it.

burn dry wood and clean the tubes every time you load it.
 
Thanks a lot guys, major help in my decision. Im going to shop around a few businesses this weekend and then get back to you's for some advice. I will definitely be taking notes as I am now.
 
is your existing electric system a forced air furnace sort of thing or electric baseboard radiators?
having to add a distribution system will add substantially to the cost. if you can just add a radiator coil in the furnace duct that will be the easiest.

I will try to apply this to my conversation with a professional and see what they say.
 
I'd want to be more than "pretty sure" I can install one of these before I planked down 10 to 15 thousand buckerinos on a new boiler setup. Any of the newer gasser style boilers need dry wood, if you don't already have a years supply put up, you're probably s.o.l. for the coming winter. You really need to start at your local building dept. first to see what is allowed & what isn't. Then too, your homeowners insurance may have issues with whatever you do. People have been forced to remove these units. Huge loss of money.

Trust me i am already doing weeks of research and planning to do another month or so before making my final decisions. I appreciate the help!
 
You better think long and hard about a forest eater AND your plumbing;
A pellet boiler will run you as much money but you can put a bypass line on it
allowing you to reduce your pellet use and tell your boiler that its not burning hard and can relax.

NYSERDA has upped its rebates for pellet burners to 47 percent of the installed cost but they
are still more expensive 2-4 times than coal stoker boilers(they have no rebate program for coal stokers).


you only have 10,000 BTU of useable heat per gallon of water AND 3/4 baseboard
will only pass 4 gallons a minute/40,000 BTU and you will not have a boiler bypass
line out there to tell the boiler its not burning very much wood to reduce its
forest consumption.




You should also look on youtube for videos of unhappy forest eater owners and theire
experiences over the years.
 
Leon, I don't know what you're trying to say with them, but your btu numbers are out to lunch. One gallon of water = 8 btus per degree of temp drop/rise. How are you getting a 1200 degree temp drop/rise?

And your bypass comments are head scratching. Your system & house needs a certain amount of heat, and if some of it is taken by the bypass then the boiler will need to run longer to deliver the needed heat. More flow around a bypass = less heat to the house.
 
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They have some crazy new rules in NYS too. Check them out on the DEC website. You'll have to have a smokestack, lol.
 
Leon, I don't know what you're trying to say with them, but your btu numbers are out to lunch. One gallon of water = 8 btus per degree of temp drop/rise. How are you getting a 1200 degree temp drop/rise?

And your bypass comments are head scratching. Your system & house needs a certain amount of heat, and if some of it is taken by the bypass then the boiler will need to run longer to deliver the needed heat. More flow around a bypass = less heat to the house.




Hello Maple1,

Using what Don Holohan has taught me;

based on 20 degree temperature drop one gallon per minute
of flow will transport 10,000 BTU

So if you were dealing with 500,000 BTU at a 20 degree drop
around a primary loop, you'd just divide by the factor 10,000
to get 50 gallon per minute:

The maximum flow rate for the trouble free flow rate in 3/4 inch
copper pipe is 4 gallons per minute so the finned baseboard
loop(s) or radiators are taking and shedding 40,000 BTU per minute.

The bypass loop tricks the boiler into thinking it is satisified sooner
by diverting part of the boilers hot water back into the boilers base
keeping the water temperature higher all the time.

The bypasss piping cross connects the feed and return water before
the pump and diverts part of that hot water back to to the boiler using
the return line warming the water that was cooled by the heating loops
radiation into the living or work space.

The other beautiful thing is that it reduces the chance of boiler shock to
a minimum too. as the wate is already hot.
 
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A 20 degree temp drop at 1 gallon per minute can transport 10,000 btu, but it will take an hour to do it.

4 gpm at a 20 degree temp drop is only 640 btu per minute.

I think in your calcs somewhere that you are overlooking that there are 60 minutes in an hour.

If the bypass tricks the boiler into thinking that it is satisfied, before the house demand is satisfied, then yes the boiler will burn less fuel. But then your house won't be warm enough.
 
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OK, the bypass loop tells the boiler its satified at its high limit and then shuts down all the while the circulator is pumping the four gallons per minute out of the boiler and let say shedding 1 gallon back into the bypass loop and back to the sump base of the boiler.

In my case I have 100,000 BTU to play with per hour with my oil burner
the boiler is 85 percent efficient meaning I lose 15,000 BTU out the chimney per hour
so I have 85,000 btu of available heat since its a non condensing boiler
The boiler has 12 gallons of capacity;
the loop has 7 gallons of capacity;
for a total of 19 gallons of water.

I am damned and riding on the ship of fools so to speak and still stuck with 85,000 BTU


IF I do this its pumping three gallons per minute through a single loop pushing 160 degree water 225 feet approximately which is an awful distance in one loop. the heat loss is 90,000 BTU which is about average (old house etc)BUT when I run the wood boiler with the temperature balancing loop/bypass loop the system works better as I have another 25 gallons of water that is heated.


The same can be accomplished with a boiler bypass diversion loop from the load to the return leg with a bypass valve on any boiler- Saying that, A forest eater would need its bypass loop tied in before the loop exits the boiler shell and would require heavy insulation to protect it.


Its fun to examine I guess, the bypass loop is returning 1 gallon per minute of 160 degree water per minute back to the boilers 12 gallons of capacity.
So 3 gallons at 140 degrees and 1 gallon per minute at 160 degrees are returning back to the boiler at all times and the boiler has 12 gallons of hot water in it at all times.

The return water is probably much colder at my place the house as the house is poorly insulated and the previous owner was a real cheapskate and used the place as asummer home.

The bypass loop is diverting 60 gallons of 160 degree water per hour through the bypass loop and back to the boiler sump while the circulator is pumping 3 gallons per minute (180 gallons per hour) of 160 degree water to the heat load and returning 180 gallons of 140+- degree water per hour back to the boiler sump to be heated.

SO one gallon per minute of every 12 of its volume is going back into the water jacket at the sump and reducing the run time of the burner. 4 GPM is still being pumped at 160 degrees through the heating load depending on the heating load of course but:

The one gallon per minute is buffering the total 19 gallons in my single loop that is making the pub crawl.


If I changed the setting to two gallons per minute the circulator would still be pumping 4 gallons per minute 240 gallons per hour throught the heat load while the bypass loop is still diverting 120 gallons per hour back to the boiler to help keep the water at 160 degrees or close to it.

If I have the math right (I hope) the boiler is not running like mad as the aquastat is not being fooled too much. I wish I was more computer literate where I could use the math symbols and The Delta P and T formula correctly.

Heating with steam with a one pipe system or a gravity system is so much simpler.

The pump people and Mr. Holohan say that the 3/4 copper finned baseboard will only
take 4 gallons per minute to work properly to heat a home.
 
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Jebatty, what about the Heatmaster G series 100 and 200 owb models? They out performed the Garn 2000 and 1500 in efficiency, emissions levels and rates.

The HeatMaster uses some poor quality components such as cheap fans, that need to be replaced every couple of years. Check out the Polar G-Series or the Econoburn outdoor boilers for better quality build and components throughout.
 
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