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[Retired]

I'll be the first to admit that I know very little about OWB's  so I would like to ask a couple questions. I currently heat my home with an older model wood burning stove ( no blower ). I can fill the stove at say 11:00 pm dampen it down and in the am at 7:30 or 8:00 the house will be 70 deg. and the stove will be full of hot ash.  This is possible because I choke the air supply down to almost nothing . Now my questions

1.   How can you fill a OWB then blow air on the fire all day or night and still get 12 + hours burn time ?  Im assuming that the blower is necessary to keep the fire hot in order to maintain the desired water temp.

2.   If this is  accomplished by useing unsplit green wood why do some Mfg. recommend using split seasoned wood ? I understand the problem with creosote and green wood.

3.   Why is it necesary to run the recirt pump / pumps 24 / 7  is this to prevent the water tank from over heating ?  If not why can't the pump be started when the furnace blower starts.  I would think the water temp would stay higher longer with out the blower on the fire if the recirt pump didn't run.   

4.   I have seen some stoves that blow air on the fire from the front and some from the back which is better ??

5.   Is mild steel or stainless better for the fire box ?

6.   Which is better a round or rectangle  fire box  or are they the same.

7.   Is a ash pan and a shaker grate  necessary ? or just convenient. ? 

Thanks 

[Scott7m]

Well... Let me help

Your indoor stove gets a little bit of air all the time, your outdoor boiler shuts off most of the time and allows no air in the fire box, or so little no smoke or flames can be seen

1.  The blower is controlled by an aquastat, it reads water temps and tells the fan when to come on and when to stop and close a flapper, this is how it saves you wood, most of the time the stove is idling and not burning..  My boiler probably kicks on an average of 10 times in 24 hours in current weather

2.  Green wood is horrible, creosote, and such a lost of efficiency, I know the math on it but would be typing for an hour.....  Basically speaking, green wood is full of water, it burns at a lower temp, you put water on a fire to put it out, right?  That's what green wood is full of..   Seasoned wood vs green can last 40-50% longer in burn times

3.  The pumps run continuous def not to keep the stove from overheating, the line we use loses very very little heat, like 1 degree per 75 ft or so...  The assumptions your makingin regards to how the furnace operates are off, and is common misconceptions..  ...

4.  Air under the fire is the best, especially if your lucky enough to have shaker grates, burns coal great that way too..  Fans on the front aren't as efficient and tend to smoke more and have lazier burns leading to lack of efficiency

5.  That's an endless debate...  Quite honestly, your big companies get great results out of each.   So I really feel as long as it's a good well made, top brand, you'll have no probes with either

6.  Fireboxes should be round IMO, they have only 2 welds vs having welds on every side and every corner, less welds, less chance for problems!!!

7.  Ash pans and shakers are great if you have access to coal and are extremely handy even for wood burners, not necessat, but man they sure are nice!

If you'd like to talk about this feel free to give me a call, my number is in my signature

[Scott7m]

More in regards to efficiency....  By forcing air into the firebox it makes a much hotter burn than you'll see in a regular or natural draft.  Hotter fires are more efficient and smoke less because more gases and particulates are burned..   

So a well made boiler burns super hot, shuts the air off, burns super hot, shuts the air off......  And so on
Your indoor stove sits there and burns slow and low, wasting a lot of the gases and particulates that can be burned under the right conditions.   

If your temp is set at 170 on your owb...  With a 15 degree differential, the stove fan and flap will open at 155 and force air to the burn, when it reaches 170 it shuts the air off and it idles until it gets back down to 155

So in regards to how can it blow air in all day and night they don't, the fan might run for 10-15 minutes at a time,  the colder it is the more often it cycles

They can go for a couple hours between firings in a lot of weather, sometimes all day if it's mild.. 

[MattyNH]

Well are my answers..some may have other
 #1 .the fan or draft door (natural draft) isn't on all day or night..Fan or draft door only comes on when there is a demand of hot water in the building or whatever your heating or when idle it to bring set water temp up to temp usually 180F..Plus these boilers are insulated..These boilers work no different than a oil /propane boiler..

#2 Far as green wood.. Yeah you can burn it...Pretty much a waste of btu's and gonna make your boiler run longer, smoke..the new epa phase 2 boiler you can't burn green wood..

#3 Well with outdoor wood boilers you need a way of keeping your indoor oil/propane boiler water hot, holding hot water tank or hot air heat exchanger hot..So when your wall thermostat call for heat or the call of hot water at your sink..The  hot water is right there... Your pipes are insulated underground

#4..Not sure..Mine blows beneath the fire.. instant hot

#5 Well everyone has there opinion on that..Mine is stainless...

# 6 well with a round fire box you have less welds and no corners...Im sure no difference at the end as long as the welds are good

#7 I don't have a shaker grate..I have  auger..No sticking the shovel in the fire box...I think auger is the way to go..I know most don't have them..No problem with nails, screws etc..

[Retired]

Thanks guys now I have a better understanding of how the boilers work.  Now all I have too do is decide which one I should buy.  I really think on an average OWB's that are currently on the market are a bit over priced.  Maybe I'll get luckey and find a good used one. 

[rhugg]

It is about the compromises you are willing to make and educating yourself so you know you are making them.

Yes, round fireboxes have less welds to fail but functionally is ound the best firebox?

Yes, the new gassifiers are more efficient but how will they last?  Are they picky about wood quality?  Higher maintenance?

Shaker grates or no shaker grates ...

Stainless in theory has stress corrosion cracking but there are many stainless units lasting for 15 years plus (maybe the quality of the stainless)

Read away, try to understand, but don't let the little things get in the way of a general good decision.

[artbaldoni]

Not sure what state you are in, I'm usually in a state of confusion, but make sure you check out state and local regulations. Many states require the newer EPA Phase 2 units and you can get into alot of hot water (pun intended) if you put in something other and get caught.
Good luck and I hope to welcome you to the fossil fuel free club soon!

[Scott7m]

If your in the market for a used boiler be very very careful...   People usually sell them for a reason

[Retired]

 
My home state is OHIO there are no EPA phase II regs here YET.  I would be very careful buying a used unit.   I'll more then likely wind up buying a new one because of the possibility of buying someones problem.

[Trint]

Retired,

I am in OH as well if your not in a hurry you can get significant discounts buying stuff at shows some times, I save a $1,000 by getting mine at Farm Science review in september.  The power show at the expo center (state fair grounds) should coming up soon, it a good show to look at several different manufactures at once.  I went last year and I think there were 6 or 8 different brands there.

Joe

[Firechaser]

I am also Ohio. Unfortunately you missed the power show it was a few weeks back. I think everyone answered your other questions. The difficulty lies in the options. There are many stove manufacturers and they all have their own points and prices. This site is great to see others opinions on brands. Also most posts on here will tell you that the right dealer makes a big difference. What part of Ohio are you in?

[Retired]

Trint

The power show is over, it was last week or the week before last.  I see it on the channel 10 news out of Columbus.  The Farm Science review is in Sept.  I hope to have a used one installed by then.   I live in eastern Knox county  about 50 miles north east of Columbus.

[Trint]

Opps,  I was in at the local implement a week ago and though they still had power show tickets out, just looked apparently it has already happend, I was off a week.  Best of luck looking, I ended up dealing with a P&M dealer in Mansfield.

[Retired]

Trint
Is the dealer in mansfield one that has units on display ?  The dealers that I have checked out around here are in name only . 

[Firechaser]

There is a Portage and Main dealer real close to you. Trail lane plumbing in Millersburg. I bought mine there.