OWB setting

[ponch458]

Central Boiler NOT!

Hello all,

I have been lurking for a while on this site and trying to gather all the info I can. I am wondering to all those who have installed an OWB, do you give any consideration to the prevailing wind when setting the unit? My question is not really concerning the smoke, but in regards to the OWB door placement. My current plan is to buy a CB 5036. Thanks in advance for all replies.

If you buy a Central Boiler don't count on the warranty. Whatever happens will be your fault. I have one I know. You will be talked down to as if you are a complete idiot. Anything that goes wrong with it will be your fault. Mine was for burning trash but green wood. I will be replacing it with one with heavy round firebox. Good boilers have always been made from heavy steel "boiler plate". I am only angry at myself for not doing better research before I purchased. I was able to patch this one up to get through the winter but I doubt it will go much longer. I recommend having plenty of boiler cement on hand for your CB. Maybe just go ahead and coat the whole firebox and door frame before you build the first fire. I think it sticks better on a clean surface. The only positive thing I can say about them is the dealer I located in Washington is a real good guy and tried to help. Please do a better job of research than I did before you buy. Good luck!

 

[leon]

wood etc.

Thanks for your reply. I have an all metal roof so I don't think roof fires will be much of a concern. I have been tending a wood stove in the house for years and am ready for the mess to be outside. So an indoor unit is out.

A wood stove is avery different animal.

With all the money your going to spend I would strongly suggest that
you spend some time at the ********** - Information on Fireplaces, Wood Stoves, Pellet Stoves, etc. home page to read about
outdoor wood boilers before you spend 10,000+ dollars on this.

With your desired set up you could purchase a Harmon SF360 with
42 gallons of water supply and place it in the area you want to install
a boiler and install insulated walls and ceiling an insulated 48 inch door
to shield it from the elements for half the cost of a central boiler AND
the harman has been hydro-tested for steam and has a better heat
exchanger and has a better warranty in my opinion.

This would give you 542 gallons of heated water storage and you can add a
second or third tank in the future.

The more thermal mass you have the better as it will require less energy to
reheat the water becuase of the heat already in the water.



This would allow you to install an atrmosperic pressure circulation system
that does not require pressurization or a pressure bladder for less money.

I do not have my hand on your wallet chain or any financial interest in
the harman or New horizons companies. I want you to work smarter not harder.

 

[Moojamboo]

Whatever you do, be wary of leon and the hearth forum. They are very anti owb and very pro thermal storage, which is ok if that is what you decide.

The forestry forum has a very good section for wood burning as well. I think the user doctorb (has he and a fish in profile) has a cb and is a great wealth of knowledge.

I love my cb e2400. As I don't have a basement or easy way to get large quantities of wood in for an inside stove, my owb was the way to go. For me it was a great decision that I would repeat. I started with an indoor stove but I got sick of smoke in house, no tie into dhw nor baseboard heat, splitting small, and moving wood multiple times. Some of these issues where to my specific situation, so rah rah one way or another in a general sense isn't useful.

No right or wrong answer, depends on your specific need. Any cheerleading 100% one way or another is to taken with grain of sand and with skepticism. If I had basement and room for thermal storage I would have of course looked at the indoor/cheaper option, just wasn't how my house was built in the 70's.

One thing to think about is how often do you start a new fire? I have a friend with a tarm with thermal storage who starts a fire every day. A new fire, with kindeling, every am. Not for me. I started 1 fire this season October 15th 2012, got a couple more weeks till I shut her down for the season.

 

[superwd6]

If you buy a Central Boiler don't count on the warranty. Whatever happens will be your fault. I have one I know. You will be talked down to as if you are a complete idiot. Anything that goes wrong with it will be your fault. Mine was for burning trash but green wood. I will be replacing it with one with heavy round firebox. Good boilers have always been made from heavy steel "boiler plate". I am only angry at myself for not doing better research before I purchased. I was able to patch this one up to get through the winter but I doubt it will go much longer. I recommend having plenty of boiler cement on hand for your CB. Maybe just go ahead and coat the whole firebox and door frame before you build the first fire. I think it sticks better on a clean surface. The only positive thing I can say about them is the dealer I located in Washington is a real good guy and tried to help. Please do a better job of research than I did before you buy. Good luck!

Not the case with me! Central Boiler has been fantastic for warranty. I have been doing HVAC since 1990 and can tell you many storys of warranty crap from furnace companys. I just had the primaryair inlet 90* sent to my dealer under warranty for my 2009 Eclassic 2300 and have also had complete door, updated fusion combuster and cleaning tools with updated manual sent--all at no charge installed by me(no labour warranty). Furnace companys do no updates for free unless it's a safety hazard so the tools and manual were a huge bonus that some will still complain about.Central Boiler is the only one I reccomend:msp_wub:

 

[ponch458]

As you are now so once was I CB6048

Not the case with me! Central Boiler has been fantastic for warranty. I have been doing HVAC since 1990 and can tell you many storys of warranty crap from furnace companys. I just had the primaryair inlet 90* sent to my dealer under warranty for my 2009 Eclassic 2300 and have also had complete door, updated fusion combuster and cleaning tools with updated manual sent--all at no charge installed by me(no labour warranty). Furnace companys do no updates for free unless it's a safety hazard so the tools and manual were a huge bonus that some will still complain about.Central Boiler is the only one I reccomend:msp_wub:

On Kebler Pass in Colorado there is a very old ghost town cemetery with a headstone of a young lady who died well over 100 years ago. The epitaph reads "As you are now so once was I. As I am now you soon shall be so prepare yourselves to follow me". I also loved my CB6048 before the geyser appeared in the door frame. It eroded completely through from the outside. No nitrate or ph issue my friend this is purely a case of too thin steel being used to cut costs. Central Boiler doesn't even want to look at this one let alone replace it. I will be replacing it with a boiler that actually uses something HVAC folks call "boiler plate". I do totally understand your enthusiasm for CB I have truly been there. I am pretty sure you will find a lot of folks who have had the same up and down experience I have with them if you look around. Let me know if you would like to see the video. I can email it to you or post it online if I can figure out how.....

 

[leon]

wood and more wood

Whatever you do, be wary of leon and the hearth forum. They are very anti owb and very pro thermal storage, which is ok if that is what you decide.
========================================================================================================================================================================

(As far a being wary of me and what ever your implying;

It all comes down to ones walllet, the laws thermal dynamics which include the basic laws of physics and the fuel supply.

I was going to purchase an Evergreen from Rick before he went out of business and I lost out of buying the Sequoiya model with 400 plus gallons of water storage. I was then going to fill the firebox half full of fire brick with a pallet and a half of full firebrick to increase the thermal mass storage and thereby increase the heat storage and also increase the amount of heat radiated back through the BOILER PLATE of the Sequoyia model.

I would have been able to use small fuel wood and create a small hot smokeless fire to heat the thermal mass of brick and then the water with a clean burn at all times and I would not create a lot of smoke becuase it would have been consumed by the combustion process and the heat radiating back into the boiler from the firebrick.

This would have allowed me to burn a hot clean fire every couple of days anyway with the firebrick radiating the heat it absorbed from the fire back into the BOiLER PLATE and then the water jacket.)


My boiler only has 25 gallons of water in it and the fire box is 12 by 24 by 36 and I have shaker grates for chestnut sized coal burning. I purchased a 12 inch by 12 inch piece of channel iron and enough firebrick to fill the boiler half full of firebrick to add thermal mass in the boiler due to its small water volume. I have not regretted making this decision becuase it burns both very hot and very clean with little smoke when its idle and the automatic damper is shut down.




========================================================================================================================================================================

The forestry forum has a very good section for wood burning as well. I think the user doctorb (has he and a fish in profile) has a cb and is a great wealth of knowledge.

I love my cb e2400. As I don't have a basement or easy way to get large quantities of wood in for an inside stove, my owb was the way to go. For me it was a great decision that I would repeat. I started with an indoor stove but I got sick of smoke in house, no tie into dhw nor baseboard heat, splitting small, and moving wood multiple times. Some of these issues where to my specific situation, so rah rah one way or another in a general sense isn't useful.

No right or wrong answer, depends on your specific need. Any cheerleading 100% one way or another is to taken with grain of sand and with skepticism. If I had basement and room for thermal storage I would have of course looked at the indoor/cheaper option, just wasn't how my house was built in the 70's.

One thing to think about is how often do you start a new fire? I have a friend with a tarm with thermal storage who starts a fire every day. A new fire, with kindeling, every am. Not for me. I started 1 fire this season October 15th 2012, got a couple more weeks till I shut her down for the season.

========================================================================================================================================================================

On Kebler Pass in Colorado there is a very old ghost town cemetery with a headstone of a young lady who died well over 100 years ago. The epitaph reads "As you are now so once was I. As I am now you soon shall be so prepare yourselves to follow me". I also loved my CB6048 before the geyser appeared in the door frame. It eroded completely through from the outside. No nitrate or ph issue my friend this is purely a case of too thin steel being used to cut costs. Central Boiler doesn't even want to look at this one let alone replace it. I will be replacing it with a boiler that actually uses something HVAC folks call "boiler plate". I do totally understand your enthusiasm for CB I have truly been there. I am pretty sure you will find a lot of folks who have had the same up and down experience I have with them if you look around. Let me know if you would like to see the video. I can email it to you or post it online if I can figure out how.....

_________________________________________________________________


The locally built boiler I own is 31 years old was built from boiler plate and at the end of its usefull life unfortunately and I will have to replace it eventually. It was hydrotested for steam use in its building and it has been a dependable boiler but its age will eventually prove its undoing simply because of metal fatigue.


Boiler plate is resistant to the issues involved with wood and coal burning being cavitation and air bubbles and always has been. Round fireboxes are the normal state of affairs for combustion chambers.

A steam locomotive fired with cordwood or coal has a circular firebox by the way.


As Ponch 458 has both illustrated and said so well, look around before you make any decision, theres no reason to hurry this issue as you need time to examine the issue completely.

A hydro tested boiler is just that, it has been tested to a high pressure to assure it does not leak with steam and hot water.

This also means that if you use it as an atmosperic pressure heating system with a standard steel expansion air tank you will not have problems for its guaranteed life span as long as normal care is used.



The right or wrong answer depends on what you end up having to; 1. live with and 2. deal with and how old your going to be still dealing with it 32 years later.

If I had the luxury of seeing thirty two years into the future I would have purchased the Vanwert coal stoker for a thousand dollars more installation cost with a burn pot instead of moving grates and not had to deal with cordwood ever and purchased a trailer load of rice coal 32 years ago and been down with it when anthracite coal was $100 dollars a ton.

I only hope that Harman changes their grate system to a "Combustion Engineering" burn pot eventually.

 

[Woodmarc]

Whatever you do, be wary of leon and the hearth forum. They are very anti owb and very pro thermal storage, which is ok if that is what you decide.

The forestry forum has a very good section for wood burning as well. I think the user doctorb (has he and a fish in profile) has a cb and is a great wealth of knowledge.

I love my cb e2400. As I don't have a basement or easy way to get large quantities of wood in for an inside stove, my owb was the way to go. For me it was a great decision that I would repeat. I started with an indoor stove but I got sick of smoke in house, no tie into dhw nor baseboard heat, splitting small, and moving wood multiple times. Some of these issues where to my specific situation, so rah rah one way or another in a general sense isn't useful.

No right or wrong answer, depends on your specific need. Any cheerleading 100% one way or another is to taken with grain of sand and with skepticism. If I had basement and room for thermal storage I would have of course looked at the indoor/cheaper option, just wasn't how my house was built in the 70's.

One thing to think about is how often do you start a new fire? I have a friend with a tarm with thermal storage who starts a fire every day. A new fire, with kindeling, every am. Not for me. I started 1 fire this season October 15th 2012, got a couple more weeks till I shut her down for the season.

This is kind of where I'm at after all my research. There are pros and cons to each set up as well as manufacture. I'm leaning towards CB based on the fact that there is a dealer close.

 

[leon]

This is kind of where I'm at after all my research. There are pros and cons to each set up as well as manufacture. I'm leaning towards CB based on the fact that there is a dealer close.

========================================================================================================================================================================


As far as pros and cons go you should ask your central boiler dealer what he or she will do with your boiler

1. if and when your boiler develops a leak during the warranty period?

2. whether he or she will remove the boiler and have it welded and returned to you at
no cost TO YOU?

3. WILL HE OR SHE PUT IT IN WRITTING so you can have the document notarised?


4. ANY BOILER that is hydrotested is legally required to pass
The National Plumbing Code Standards for steam pressure and
hydronic heating pressure in all fifty states.
a. any boiler that is hydrotested has boiler plate in its contruction.


Spend some time and look at what is required for steam heating boilers, especially the cavitation corrosion issue and at the type of welding rod or welding wire and whether the stainless steel is welded with inert gas sheilded wire or core wire or unsheilded wire welding AND THE TYPE OF WELDS that are required to weld both boiler plate and stainless steel to pass inspections.


The one thing that I remember that Rick did with any of his boilers was that if
they developed a leak he paid to have them repaired on site in most cases or had them brought back to him to be repaired if needed.


The one thing I would also suggest is that you contact the attorney general in you state and see how many complaints the central boiler company has pending against it nationwide as well as any settled cases before you make a decision about spending this amount of money.


Once your money is gone ITS GONE AND YOUR BANK IS STILL REQUIRING A PAYMENT EVERY MONTH.

 

[mtfallsmikey]

5 yrs. on my CB5036, still going strong. These boilers are run as an open system.

 

[Cheesecutter]

I'm not saying an OWB is for everyone because they aren't. However I think if you ask 99% of owner if they would buy another, they would even if its not by the same manufacture. They may not be perfect, but 1/2 the people in my neck of the woods have them.

 

[Guswhit]

If you buy a Central Boiler don't count on the warranty. Whatever happens will be your fault. I have one I know. You will be talked down to as if you are a complete idiot. Anything that goes wrong with it will be your fault. Mine was for burning trash but green wood. I will be replacing it with one with heavy round firebox. Good boilers have always been made from heavy steel "boiler plate". I am only angry at myself for not doing better research before I purchased. I was able to patch this one up to get through the winter but I doubt it will go much longer. I recommend having plenty of boiler cement on hand for your CB. Maybe just go ahead and coat the whole firebox and door frame before you build the first fire. I think it sticks better on a clean surface. The only positive thing I can say about them is the dealer I located in Washington is a real good guy and tried to help. Please do a better job of research than I did before you buy. Good luck!

I really find this odd with the few service issues that arose while I was installing mine. My dealer was exceptional when it came to helping with my very small problems. Of course we do not have the whole story behind the age of the unit and what not, but things can happen with any product. I am on my 4th full year now and the stove has been flawless(only operator causing problems).

 

[ponch458]

Yep

I really find this odd with the few service issues that arose while I was installing mine. My dealer was exceptional when it came to helping with my very small problems. Of course we do not have the whole story behind the age of the unit and what not, but things can happen with any product. I am on my 4th full year now and the stove has been flawless(only operator causing problems).

Yes that was my experience as well until the catastrophic failure occurred. I bragged about mine to anyone who would listen. And maybe you will have better luck. I certainly hope you do. However, I live in the weeds in Alaska where the freight is generally more than the item. I bought Central because I figured they were a safe bet since they have the big warranty. I haul my wood on a 15 cubic yard dump truck and burn 20-25 loads per year. In my world the actual warranty doesn't mean much. Unless something fits in a Post Office Box we don't send it back. Quality is extremely important when you are out here. Unfortunately the quality I thought I was getting was smoke and mirrors. The good news is in this little community (State of Alaska) most everyone will be aware of my experience.

 

[Richard@PM]

stack extensions and thermal mass

If you want to add a huge water tank inside your house go for it, Or buy an outdoor unit and fill it with wood once per day and be done with it. The stove pipe on my hardy is 3 ft tall and shoots a flame out of the top of it. It really lights up the night. Yeah they burn more wood but they don't burn your house down and you never haver to sweep the floor.

Once you have an owb you will laugh at indoor units.

Indoor or outdoor at least you'r not burning oil but here are a couple of suggestions. #1 don't add stack unless you have to and if you do then keep in mind you just increased the draft and your stack temp will rise (wasting heat up stack) solve the problem by installing a barometric damper @ the breach just like the oil industry has been doing for many years. Mass storage on an outdoor boiler is not typically needed unless you are using it for something like greenhouses where the boiler might be dormant all day and then once the sun goes down there is a huge demand for heat and the boiler will have a hard time catching up. I'm new to this site but have been installing and servicing wood boilers here in the northeast for almost 10 years, above all do your research before you spend your money!!!!

 

[leon]

Owb

Indoor or outdoor at least you'r not burning oil but here are a couple of suggestions. #1 don't add stack unless you have to and if you do then keep in mind you just increased the draft and your stack temp will rise (wasting heat up stack) solve the problem by installing a barometric damper @ the breach just like the oil industry has been doing for many years. Mass storage on an outdoor boiler is not typically needed unless you are using it for something like greenhouses where the boiler might be dormant all day and then once the sun goes down there is a huge demand for heat and the boiler will have a hard time catching up. I'm new to this site but have been installing and servicing wood boilers here in the northeast for almost 10 years, above all do your research before you spend your money!!!!

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

Quoting your part of your posting:

Mass Storage is not typically needed unless you are
using it for something like a greenhouses"



How can make a statement like this when the laws of physics and
thermo dynamics are all in favor of the storage of heat energy
for its later use?

In this case-
"One calorie will raise the temperature of one gram of water one degree Celcius".

The Russsian or Finnish masonry stoves also make use of thermal mass and small
very hot fires to heat homes all over the world in cold climates.


We have one member here that has a huge thermal mass wood boiler that he
feeds once a week or so to heat his buildings using wood and a skid loader.

We also have a number of members on AS with mass storage for thermal mass, my boiler
only has 25 gallons of water in it and I filled it half full of firebrick and I wish I had done
it 31 years ago.

 

[Richard@PM]

Mass storage

Leon one of us is confused and I think that we are talking about 2 different animals, for example our 250 has 240 gallons of water mass by itself and the boiler's dry weight is 3030 lbs. most of which is refractory brick and solid 1/4 inch steel inside of the insulated jacket.How much more mass do you think an average home of 3000 feet needs? Another reason for not adding more mass is that the refractory needs to stay hot therefore,we don' want you to consistantly let it go out as heating the water mass back up again takes considerable time and in that time you are promoting condensation within the boiler, again 2 different animals 25 gallons of mass and boiler weight as opposed to 240 gallons and 3000 pounds of steel and brick. our boiler only requires extra mass on large very sudden heat loads. If you have any more questions or comments please feel free to ask but please don't try to make me out to be a nit wit, I know what works well in our boilers and as well most of our competitions Outdoor Wood Boilers and do not pretend to be an expert in the much smaller indoor units as I certainly prefer the OWB's

 

[leon]

owb

I never inferred anything about you or anyone else here on the forum and
never have, nor would I do so.

I do not have issues with condensation in my pressurised boilers combustion chamber
so thats not an issue for me and never has been.

The mass of fire brick gets hot and stays hot for hours after the fire goes out.

I simply said a large thermal mass benefits from the laws of thermal
dynamics.


I filled my combustion chamber half full of firebrick.

The volume of firebrick is amost half the volume fo the combustion chamber
which is 12" by 24" by 36" the volume of fire brick is 12" by 12" by 36" as
it sits on the 2 inch channel iron covering half the coal grates.


The firebrick makes a huge difference as the fire brick absorbs heat as well
as sheds it back into the boiler plate radiating as one solid mass to the water
jacket on all three sides and it helps a lot because my house is so old and
poorly insulated.

This is why I emphasize to anyone that they will gain more if they fill these things half
full or more of firebrick as the heat in the brick aids in burning up the smoke in the
combustion chamber.

I am genuinely sorry you feel that I slighted you but I will offer you an apology.

 

[Woodmarc]

Indoor or outdoor at least you'r not burning oil but here are a couple of suggestions. #1 don't add stack unless you have to and if you do then keep in mind you just increased the draft and your stack temp will rise (wasting heat up stack) solve the problem by installing a barometric damper @ the breach just like the oil industry has been doing for many years. Mass storage on an outdoor boiler is not typically needed unless you are using it for something like greenhouses where the boiler might be dormant all day and then once the sun goes down there is a huge demand for heat and the boiler will have a hard time catching up. I'm new to this site but have been installing and servicing wood boilers here in the northeast for almost 10 years, above all do your research before you spend your money!!!!

I have been looking into these owb's for a few years, and have been searching AS reading everything I can to make an informed decision since this is a significant investment. Since you have been installing these for 10 years I would certainly love to hear any opinions/advice you would be willing to share.

 

[leon]

owb

I have been looking into these owb's for a few years, and have been searching AS reading everything I can to make an informed decision since this is a significant investment. Since you have been installing these for 10 years I would certainly love to hear any opinions/advice you would be willing to share.

====================================================================


In order to make a sane decision you should also become a member
of the ********** - Information on Fireplaces, Wood Stoves, Pellet Stoves, etc. web site.

I would also advise you to read the posts and threads regarding
outdoor boilers there as there are Hearth members that disposed of
their outdoor boilers for a number of reasons, one of which is the
amount of firewood consumed annually.


Unburned smoke is lost heat energy lets not conveniently forget that fact.

A couple of years ago now the city of Geneva, New York Banned outdoor
wood boilers entirely as heating appliances. The owner of OWB fired up his boiler
and it shut down after the demand load was satisfied and smoked out the
entire neighborhood. Shortly after this he was cited for creating a helath hazard and
forced to cease and desist the use of the boiler. If he had a very large thermal storage
mass of water or firebrick in his combustion chamber he would not have had this issue.

 

[Richard@PM]

Advice on you'r decision from an OWB and indoor boiler sales and installation guy is

talk to local dealers/installers and make up your own mind. Here are a few things to look at,OWB's are much less labor intesive(much less moving of wood,larger peices,no smoke or fire hazard inside home,12 hour burn time,and no wasted space inside of your home taken up by wood and water storage or fire clearances for the stove,also no need for second flue in chimney,cleaning/ chiney fires) I personnally never liked the idea of 1000 gallons of water stored in the basement nor do I like the idea of starting a new fire every couple of days,obviously leon does not mind these and thats great, thanks for burning wood Leon but reading your reply I believe you are interested in an Outdoor Wood Boiler. If this is true then here are some things I look at, #1, see one burn, I burn my 250 at approximately 20 shows per year and as I did this weekend I fire them up on my trailer for potential customers to see,#2, weight of boiler, steel and firebrick,#3, what type of heat exchanger ( the 250 has a true 3 pass) this allows us to reduce exhaust temps to below 300 degrees(less heat escaping up the stack and more absorbed into the water) There are many different brands out there and most are pretty good I will not bash any of them as they all burn wood, however if you see me at one of my shows there will be a stack temp guage on my boiler, ask any of my competition to show you their boiler running and see what their stack temp is. I'm running out of room but if you still need more answers feel free to reply.

I have been looking into these owb's for a few years, and have been searching AS reading everything I can to make an informed decision since this is a significant investment. Since you have been installing these for 10 years I would certainly love to hear any opinions/advice you would be willing to share.

 

[leon]

Owb

I am not bashing anyones brand of boiler.

a. the simple fact is they are not building a high efficiency boiler using the common existing practices of high combustion efficiency by making multi-pass combustion chambers(not unlike like the Russian or Finnish wood stoves but by using smaller combustion paths and in effect losing much of the heat produced by the act of forced draft combustion.

b. The reason the higher efficiency combustion chambers are not being used is simply one of GREATER EXPENSE AND LOWER PROFIT MARGIN.

I have no interest in purchasing any of the currently offered outdoor wood boilers for many reasons which are listed by their importance;


1. lack of a fully firebrick lined fire box.

a.The Lil Albert and and Big Boss Man units that rick built were excellent
examples of outdoor wood boilers that had fully lined fireboxes and large water
volumes that could and would burn wood, anthacite coal, and corn cobs using a
forced draft combustion system and front to back shaker grates.
.
b. If I had the money at the time to purchase the Lil Albert, the Big Boss Man or
The Evergreen Sequoya with coal grates from rick and filled them half full of
firebrick I would have!!!!!




2. low volume of water storage(less than 2,000 plus gallons).

a. thermal mass for hot water storage.

b. the ability to burn large rounds which decreases the boiler
efficiency because less wood fiber is exposed to combustion(which is why I
split my firewood into very small pieces to aid in combustion. It take a bit
more work but the lack of smoke exiting my chimney is proof enough.


3. The square or rectangular fireboxes are too large, which permits the
end user to add a very large amount of wood which in the end chokes the bed
of coals and as result creates more smoke due to incomplete combustion with
a forced draft fan combustion cycle. Size does matter in this case.

These boilers and thier overall efficiency can be improved by filling it half full or more of firebrick to add thermal mass and create a heat sink to radiate heat back into the combustion chamber.

4. The lack of water volume also increases the number of times the boiler MUST
CYCLE to temperature for heating water to heat ones home and domestic hot
water.


a. a small firebox permits the user to run a hot fire continuously and maintain a
very high combustion temperature at all times when burning nearly
eliminating and smoke due to the high combustion temperature.

a1.this also ties in with a having a fire box lined completely with firebrick or
having half or more of its combustion chamber filled with firebrick which
creates passive thermal mass 2. creates a heat sink. 3. radiates heat back
into the firebox.



The gentleman I purchased my natural draft boiler from offered at one time an exhaust gas scavenger that would be placed directly behind the the boilers flue pipe and was built up to 32 feet long with 4 heat exchanger pipes in the rectangular box that was used for either water or forced air heating AND IT PULLED THE HEAT EXITING THE FLUE PIPE AND ABSORBED IT IN THE WATER or AIR SURROUNDING THE FOUR PIPES IN THE RECTANGULAR BOX HEAT EXCHANGER leaving a very low temperature stack temperature indicating that there is vert little heat exiting the chimney.

This allowed the end user to extract even more heat from the flue gas exiting the combustion chamber leaving little to any smoke exiting the chimney.

The "hybrid" induced draft multi pass heat exchanger wood only boiler he designed and built and sold was based on the steam locomotive fire box in design and he has sold many of them.


It all comes down to profit and loss.

Crappie Kieth and I both agree on the above items items completely.

Kieth sells firebrick for pizza ovens that is molded into a 12 by 12 square
that can be used in a wood boiler or a wood furnace combustion chamber
for themal mass.

The simple act of splitting your firewood very small aids in its combustion
because it will season faster as more of the wood fiber is exposed to drying.

Yes it takes more time and effort but the fire will burn hotter and cleaner.
Burning a small hot fire reduces smoke to a minimum.


Unfortunately for the builder there is less profit in a boiler with a larger water mass because it
cost more to fabricate and weld and also why some builders use stainless steel or steel plate
rather than boiler plate as standard material in construction of an outdoor wood boiler.


If several close neighbors got together to invest in a OWB that also burned coal that heated 4 or more homes with hot water or steam and domestic hot water they would save a considerable amount of money to make domestic hot water and hot water for heating with an air ot water heat exchanger or to create steam but I believe that the limit of homeowners that could become a combine is 4 homes to avoild the systems becoming classified as a utility per current laws.


I do not know how many OWB builders have thier units hydrotested either as a matter of business.


If someone builds a more efficient wood and coal outdoor boiler with BOILER PLATE, heat exchanger tubing submerged in water, coal grates or a coal stoker with a Combustion Engineering Underfed Forced Draft Firepot using a fully lined febox I will gladly let them install it for TESTING ONLY to heat my home and hot water.I do not see it happening though.


The thing is that good boiler design has been in use for many years and the idea of using a square firebox is not new.

The issue remains that Cavitation Corrosion is ever present and some metals do not tolerate it very well if the metals thickness is an issue in construction in some cases where wide temperature extremes from water transfer from the boiler to the heat load and back to the boiler do several things:

The act of combustion creates a temperature swing in the firebox material that forces it to expand and shed heat to the water jacket.

The act of heat exchange creates temperature swings, where the heat of the combustion process rises and immediately begins heating the steel above the fire and the water heats and creates air bubbles which must be purged with a de-airator otherwise the water turns to steam and is trapped.

A circular firebox presents the most amount of square area to a heat source in one continuos plate of steel surrounding the sides and top of the firebox. The sheet steel thickness also aids in the act of heat exchange.

The rear of an owb or an owcb has a water mass facing the firebox as well adding to its complexity.

Some builders use welded stays separating the interior and exterior walls of the firebox in their construction which was copied from the construction used in building locomotive boilers using riveted plating.

The ash pit is the only area that typically has no water underneath it in most models that I know of.

The act of heating and reheating water creates a chemical chenge in the water supply used in the boiler this also affects the steel used in the boiler because the water will become more acidic and attack the steel in the combustion chamber which requires the end user to add water stabilising chemicals to neutralise the PH level.

Cast iron sectioned boilers and radiators used for heating are much more resistant to this due to their sandwiched construction which expands and contracts.


Good boilers have been built for many years, hydronic heating is an outgrowth of steam heating and a poor one at that simply because the hot water is poor medium for heating versus low pressure steam where much less water is needed to create heat and domestic hot water. radiators and air plenums should not be installed near windows and only on interior walls anyway in my opinion simply because a window is an automatic
way to lose heat.