10+ years experience with woodboiler and thermal storage - lessons learned

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Lance Stronk

Member
Oct 22, 2013
9
Northfield, CT
Hi. I have a gassification boiler that I have been running for about 10 years now. I figured putting some info out there couldn't hurt.
I installed a Tarm wood/oil boiler in 2013. It was new to me and a learning experience. Nothing an engineer couldn't tackle.
I had a plumber do the copper plumbing of the furnace and the 620 gallon thermal storage. It is a bit more complex than your run of the mill oil boiler, but I had it up an running shortly after the plumbers left. I wired everything up myself - doing all the research to ensure I would have a bulletproof design....electrically.
The furnace operated nicely. Dry wood is the key for smooth operation of the gassification boiler. You can use wood that is 'less' dry (>20%), but you'll be fighting the furnace until everything is up to temp and there is a nice coal bed.
After about a year or so of operation, I noticed that the refractory in the firebox was deteriorating. Basically, air blows into channels at the bottom of the firebox and things get HOT...upwards of 2000F. Over time, that heat, generated by the pyrolized wood and air, burns up the refractory. It's unavoidable.
So, I called for a replacement refractory and apparently they had changed the design of the firebox and had another solution where instead of the entire firebox base replacement, you replace what I will call sacrificial refractory sections. This is fine if you have that design upgrade to start with, but changing over to the new design cost (and this is a guess as I don't recall exactly) upwards of $500. OK OK....the cost of running a gassification boiler. I still have a little to go to break even over the cost of the system by burning wood, so that's the way it goes.
The next issue was electronics. A failed flue temp timer....another $50-100? Meh....I'll eat that again. What choice do I have?
The next issue was more refractory. The flame tube that receives all the heat and disperses it under the refractory up through the boiler tubes crumbled. Again....$400 maybe.
So, after 10 years and a system that probably cost me $20K for the furnace, thermal storage and install, I am faced with another gem. The thermal storage heat exchangers (1" diameter corrugated stainless) have pinhole leaks in the coils. Not sure if this is from cathodic reaction. Everytime I fire the furnace, the thermal storage tank overflows. The upside is that I don't have to periodically add water (due to evaporation) to the thermal storage tank (that's not really an upside). New coils will cost me $2500.
Burning wood and heating my home with wood is great. However, the complexity of this particular system leaves a lot to be desired. On the surface, you may think you are saving money, but in the long run you may be losing. There is no such thing as zero maintenance - that is for sure,
Not sure I would do a system like this ever again.
The thing about hitting yourself in the head with a hammer....it feels good when you stop!
 
All in all, what would you have spent to heat your house with your conventional system. Are there savings? Let's not include the cost of the Tarm. Your house purchase included the existing furnace. Do you buy your firewood or process it yourself?
 
I hear ya, but processing wood is kinda like exercise...well it really is. It's good for the mind. Self sufficiency.
For me, 20 plus years later, I still love running a saw. I'm an arborist and do it almost daily. Also like to split wood. Especially with hydraulics. I try and handle the wood as few times as possible. Just trying to give ya a silver lining. LOL
 
So i would like to add my 14 years of using a gasification boiler with 1000 gallons of storage.
My system is quite a bit different but the same...
I built the system myself except for the wiring,which had to be done by a licensed contractor as my home is in an industrial area.
Boiler is an Econoburn 200, the original control went at the start of season two, i ran the boiler off of temporary wiring using the high limit aquastate as the shutoff. Had the main plug burn off the replacement controller after about 8 years, which i fixed ans is still working for a backup.
I have a sealed system, no leaks in 14 years.
I run glycol in my underground lines and home, i have a big plate to plate heat ex-changer which works great as my system is sealed there has been no buildup or cleaning required so far
I clean the flue tubes about every 2 1/2 cords of spruce used, this takes me around 4 hours from start to finish
I am on my 3 rd nozzle in the upper burn chamber, it is made to replace and takes maybe a couple hours to replace
My system has been dead simple to maintain and use, after the initial startup in the fall it runs from October to May using around 8 cords of spruce for the burning season.
When i was married the X had zero issues starting a fire of keeping the boiler going till the storage is up to temp. On our average winter day -20 C the boiler gets fired at around 5 PM and has the storage to temp by 10-11 PM
I have vintage cast iron rads through out my home
I have an oil fired boiler for back up which is on the house side of my heat exchanger, so if i am going away i can turn one valve and the oil boiler will only heat the house and not the storage by ghost flows
I am thinking of building a similar system for the new shop i am building
 
For me I'm at 5 years on my Froling pressurized boiler with 1000gallons of storage and no issues. I did the wiring and plumbing my self. One peace of good advice I received and agree with is do a slow start up for your first burn every year. If the refectory has been sitting or is installed new it has moisture trapped in it. I was told to do a small fire and leave the doors cracked allowing the refectory to heat up slowly (ie not gasify and reach 2000°F) allowing the moisture time to escape, not turn to steam breaking the refectory. From the looks of my refectory I'd guess ill get 10years out of it, burning around 6 cord a year.
 
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Seems like a woodstove or 2 in the house is so much simpler?
 
Seems like a woodstove or 2 in the house is so much simpler?
I my case i had two people living in the house with ashama
Plus i did not want a flame source in my home as i don't have insurance. I live in a rural town in a log house with a volunteer fire department. Those three things just bring dollar signs to insurance brokers.
Having the mess and smoke from burning wood in a separate building is worth any hassles and the walks to stoke the boiler at -40 C
Plus i have a warm workshop 24/7
 
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So i would like to add my 14 years of using a gasification boiler with 1000 gallons of storage.
My system is quite a bit different but the same...
I built the system myself except for the wiring,which had to be done by a licensed contractor as my home is in an industrial area.
Boiler is an Econoburn 200, the original control went at the start of season two, i ran the boiler off of temporary wiring using the high limit aquastate as the shutoff. Had the main plug burn off the replacement controller after about 8 years, which i fixed ans is still working for a backup.
I have a sealed system, no leaks in 14 years.
I run glycol in my underground lines and home, i have a big plate to plate heat ex-changer which works great as my system is sealed there has been no buildup or cleaning required so far
I clean the flue tubes about every 2 1/2 cords of spruce used, this takes me around 4 hours from start to finish
I am on my 3 rd nozzle in the upper burn chamber, it is made to replace and takes maybe a couple hours to replace
My system has been dead simple to maintain and use, after the initial startup in the fall it runs from October to May using around 8 cords of spruce for the burning season.
When i was married the X had zero issues starting a fire of keeping the boiler going till the storage is up to temp. On our average winter day -20 C the boiler gets fired at around 5 PM and has the storage to temp by 10-11 PM
I have vintage cast iron rads through out my home
I have an oil fired boiler for back up which is on the house side of my heat exchanger, so if i am going away i can turn one valve and the oil boiler will only heat the house and not the storage by ghost flows
I am thinking of building a similar system for the new shop i am building
I was looking at those boilers, but since it failed the epa requirements, I don't think you can buy them anymore? Can you still get parts?
 
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I was looking at those boilers, but since it failed the epa requirements, I don't think you can buy them anymore? Can you still get parts?
So far no issues getting parts required
I know that during covid they were not able to do testing on their new models
I am assuming that they would be back to normal and have testing done or scheduled.It didn't sound like they were going out of business. But nobody admits to the fact they are shutting down a company
 
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