# Outdoor wood boiler



## lreigler (Dec 23, 2009)

Here to hear a few thoughts from people with experience with outdoor wood boilers. I’ve been in my home for 8 years now and have ran an outdoor wood boiler every winter from October to April. It’s a central boiler classic and has been installed for close to 20 years. It uses a ton of wood to keep the water up to temp, I figure close to a face cord of wood per week. I’ve tried to calculate over the years my savings as I cut all of my own wood off of my property, and figure I spend roughly three hours per week of my time cutting, filling and maintaining it. It’s also quite a pain whenever we want to go away if temps are below freezing and it needs filling. I typically fill the box twice per day

I’m at the point where I’m considering other options. A few things factor into this. One, the boiler is getting old and parts are corroding and more will need to be added to make it functional. Two, all of the dead ash on the property has been cut and burned, meaning for optimal performance now I must cut and season, adding time/work. Three I have determined the lines running from and to the boiler are poorly insulated and are not efficient.

I have propane as a backup to the furnace, no natural gas lines here. I think I have a few options.

A) for go the entire boiler and just use propane. Probably the simplest option, but I would be at the mercy of higher annual costs and fluctuations in price.

B) Forget the boiler and install a pellet stove in the basement. I would still have pellet expense, but would be able to just purchase the pellets and use as needed to supplement heat.

C)Buy the wood in bulk and continue to use the boiler. Hopefully finding a source with seasoned wood or logs and eliminating my time and expense working in the woods. 

I'm also considering the expense of reinsulating my house with injection foam to help the efficiency and reduce long term cost. 

I’m interested to hear the thoughts. Thanks for reading


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## FullQuiver (May 2, 2006)

Everything is a tradeoff. Right now with what is going on with oil and electricity prices and instability I am going away from wood. I would better insulate the lines going to the house, fix up the boiler and get out and cut some wood.. 

However, I have always burned wood, tried propane for half of one season many years ago and just couldn't pay the long dollar wanted for propane. Besides I kind of like cutting and putting up wood..

To each his own..

BTW pellet stoves unless you get a very good one have their own set of issues.


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## grapestomper (Jan 9, 2012)

Not sure what you keep your boiler temp at but I turned mine down to 145 and it heats the house just fine. 
I fill once per day now other than below zero weather. The fan motor runs more but I don't care,
More insulation is better. Your underground line is the key. Needs to be insulated as best you can.


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## lreigler (Dec 23, 2009)

grapestomper said:


> Not sure what you keep your boiler temp at but I turned mine down to 145 and it heats the house just fine.
> I fill once per day now other than below zero weather. The fan motor runs more but I don't care,
> More insulation is better. Your underground line is the key. Needs to be insulated as best you can.


I agree, I know my underground line is the key and I lose heat as it melts snow on the ground. I did a makeshift delta T test and figure I’m losing about 40 degrees from start to finish in the run.

I do keep it set at 170 and the damper closes at 185. Maybe moving that down would be the ticket. I thought I read somewhere once that the lower temps causes an issue somewhere with condensation. I’d have to re look that up.

I looked into replacing lines with insulated thermopex. That stuff is not cheap. I figure I’d have roughly 1500 in lines alone.


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## Fishndude (Feb 22, 2003)

How much do you earn at work? I am asking because the 3 hours/week of labor for maintaining your wood supply could be spent earning income from a job (unless you are retired), and then you'd just have to stack wood someone else cut, and delivered to you. The monetary value of time, right? 

On the other hand, I'm sure technology has improved in the last 20 years, and a new high-end wood boiler would be more efficient than the one you have. And, for the record, I don't burn wood, and don't own a wood boiler. But I did work for someone who sold them, many years ago.


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## grapestomper (Jan 9, 2012)

As long as your boiler box around your fire is good most of the other parts are fairly cheap. Pumps and solenoids. Maybe a blower motor every 5-8 years. I have the insulated pex then built a 2" insulated box around it. Works good, but you can still see heat loss in the spring. I cut my own wood also. I don't mind it. I just dump in a pile though next to burner. I don't spend time stacking. Simpler the better for me.


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## lreigler (Dec 23, 2009)

Yeah I looked into the tube that runs to my house and it looks like the lines are just wrapped in cheap foam insulation. I’m considering injection foam into the tube to better insulate. Going to try to figure If that is a job I can do myself.

Your method of the insulation with the box would be ideal.Unfortunately that would require digging all new lines for me.


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## 22 Chuck (Feb 2, 2006)

Many yrs ago the fellow installing my boiler said "insulation dont cost-it pays."

When you run out of trees or get tired of cutting-get hold f one of these pulpers up here and get a load delivered-or split w/ someone.


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## tmanmi (Sep 20, 2005)

The new boilers have to meet EPA regulations that changed a few years ago. They require more seasoned wood to perform optimally. If you don't burn seasoned wood they supposedly gum up and are a pain to clean. You can supposedly get the older style for "non-residential' applications. I'm on year 13 with a Central Boiler Classic 6048 and have had no issues. I spent the money on the quality insulated tubing with around 150' in the ground. I lose about 4 degrees from the boiler to my furnace. If the temp stays under 15 all day I sometimes have to add wood twice a day, otherwise only once. I will burn around a face cord a week when it is that cold as well. 2,300 sqft 2 story with full basement built it 2000 with fiberglass insulation in 6" walls.

With the cost of a new boiler you might want to look at geothermal.


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## lreigler (Dec 23, 2009)

Yeah, I have a cl4436 so my firebox is smaller than yours, resulting in more fills. I think I’m going to spend the money to insulate the lines, and my house better, and ride it out for a while. I just bought propane today at 2.80 a gallon, so that was a bit of incentive to stay behind the saw.


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## kroppe (May 7, 2000)

If I were in this situation I would put the options in a spreadsheet. It's capital investment (up front cost) vs operating expense. 

1. Replace the existing wood fired system
2. Propane
3. Pellet stove
4. Fuel oil (not sure from the OP if that is the original system)
5. Electric heat (didn't see this mentioned above)

For each option, list:
a. equipment purchase cost plus installation
b. annual operating expense for fuel


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## lreigler (Dec 23, 2009)

kroppe said:


> If I were in this situation I would put the options in a spreadsheet. It's capital investment (up front cost) vs operating expense.
> 
> 1. Replace the existing wood fired system
> 2. Propane
> ...


I’ve done this already. The hard part is speculation of fuel cost, and longevity of equipment. I just paid 2.80/gallon of propane last week, last fall paid 1.89. My boiler is almost fifteen years old. Maybe ten more years in her life, maybe one.


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## Ronnie D (Dec 8, 2020)

Look at the Maxim by Central Boiler. I've installed a few of them and clients run them primarily on shelled corn, wheat, cherry pits and other misc. bio- fuels. Not as efficient and more ash than pellets but cheaper to operate and store than wood or l.p. Add the auto hopper and fill once a week, I - phone compatible and if a secondary heat exchanger is installed in the loop it will also supply potable domestic hot water eliminating the need for a hot water tank.


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## Ronnie D (Dec 8, 2020)

Correction on post. You would still need the hot water tank for storage, just no need for the burner to fire unless back up fuel is present


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## jjlrrw (May 1, 2006)

Depending on 

When you are measuring the 40 degree loss is the furnace blower running? When we had one the loss was less than 2 degrees the boiler was 100' from the house (measured when system was not calling for heat blower off). When I installed the boiler I placed 2 thermocouple wires in the pex pipe where it exited and returned to the boiler and I could just plug into a meter and get the temp.

I agree leaving in the winter is a pain, is your heat exchanger for the boiler installed in the backup propane furnace? If so I have heard the propane will keep the boiler water from freezing if the fire goes out as long as your pump keeps circulating the water but I never tried it.


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## KingHingeCut (Oct 15, 2020)

20yrs is a long time for one of those. I'd keep running it and get better underground pipe. Check out z supply they are out of grand rapids they have really good pipe for a good price and it's not the junk badger pipe either. If you have any extra money to insulate the home better that would help also. Be careful with running your temps low especially with having bad pipe I bet your return temps are very cold which can eventually rot your stove out from the metal sweating in the fire box.


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