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Building A Wood Stove Boiler System For Greenhouse Heating

I am building a wood stove water boiler heating system for our off grid winter greenhouse using an antique wood stove water boiler and two 55 gallon steel barrels. This will work using the thermosiphon effect and will have no moving parts and no outside power source to run it.


In a thermosiphon the water flows on its own without any outside source of power. As long as the heat from the wood stove is continued, the water will flow on its own. A thermosiphon works because hot water is lighter than cold water. The hot water will float on the colder water in the wood stove boiler. The heavier cold water will push its way into the water boiler. This will push out the lighter hot water which will flow into the water tanks. The cycle will continue on its own, pumping water with no outside source of power.


The core of this system is an antique Sears Roebuck & Co wood and coal water boiler from about 1890. This has the Sears name and under that it says "The Worlds Largest Store". This tells me it was quite a while ago. Under that it says "No Hot Pot 30".




Antique Sears Wood & Coal Water BoilerAntique Sears Roebuck & Co wood and Coal Water Boiler


I used this old wood stove in my off grid camper years ago when I started The Off Grid Project full time. Back then I lost my job and my apartment in the same month and moved into the old dilapidated camper. The camper was parked on some land I rented for $200 a month. I moved into the camper in the middle of a blizzard and this old wood stove was my only source of heat.


You can see my first video from back then right here:Origins Of The Off Grid Camper

In the video link above you can see this old wood stove in use in the off grid camper during my first day full time off the grid and living in a camper.


Things have come a long way since then. I then got an RV and renovated that. I lived in that for a year. Later I demolished the rotted old camper which was my first home and built an off grid tiny house on wheels on that trailer frame. That was just over two years ago now.


I had two 55 gallon barrels in the off grid greenhouse that I planned to use for my water boiler heating system but the other day I discovered that both of them have defects and cannot be used for this project.


So I got my old Simplicity garden tractor running and hooked up a trailer. I sorted through my steel drums and found two barrels that are in good shape inside and out. I hauled these over to the greenhouse and took the other barrels back to the stock pile.


Inside the off grid greenhouse I put the two inch fittings on both barrels. I made a wood frame on the ground using treated lumber to keep the barrel off the ground. This will reduce rot and rust on the barrel over time. I then put the second barrel on top of the first barrel and made an improvised frame to hold that one in place for now. I will build a proper frame and secure it permanently to the walls of the greenhouse later. But for today I want to get the plumbing finished in the greenhouse.


I made fittings for the two barrels to connect the two 2 inch openings together. Hot water will flow from the top of the wood stove boiler into the top of the first barrel. Then water will flow between the two barrels through the larger openings. Then cold water will return from the bottom of the lower barrel back into the bottom pipe of the wood stove.


I got the two barrels connected together in the middle but then found that my wood stove sits too high on its legs to work properly. It may work but I do not want to take any chances. Once I make the fittings and glue in the pipe, there is no changing it.


Building A Wood Stove Boiler Heating System


I may have to take the legs off the stove. The bottom pipe fitting on the wood stove boiler is 6 inches higher thatn the bottom fitting on the lower barrel. This means that I would lose some pressure in the system with the cold water needing to travel uphill. This is not good.


I will have to continue in the morning and figure this out. I still have to get a fire going in the off grid water and battery shed to prevent the water from freezing.


Back insise the off grid tiny house on wheels Melanie was baking her own homemade dinner rolls. She bakes just about everything that she needs out here on the homestead.


Earlier in the day I had cut and prepared some pallet wood coffee coaster blanks for Melanie to finish. I prepare the raw pallets and Melanie does the wood burning. We are making beautiful pieces of art and useful things out of recycled pallet and barn wood.


We have tea lights, wall sconces, wall hangings and coffee coasters so far. We are going to be adding picture frames, furniture and more soon. I take raw pallets and separate the boards. Then I removed the nails and run the wood through the planer. Pallet wood is quite beautiful when it is planed to expose the clean wood inside. Then I cut the pieces and do the wood work and hand the pieces off to Melanie. She is very talented and burns images and words into the pallet wood blanks. Then I varnish them for a finish and we sell the final products.


You can find our recycled pallet and barn wood products on our store here:


We are going to be adding more products to the list all the time to please bookmark the site and keep checking back often.


The snow is covering the ground all over the land these days and it is not going away. The cold of winter has set in and is staying. This is good news for the off grid tiny house solar power though. Solar panels are more efficient in the cold. And the snow is reflecting the sunlight and increasing the available solar power we have. In winter this is a good thing because we have shorter days and reduced sunlight hours.


You can watch the video of todays work here: Working On Greenhouse Wood Stove Boiler System


While you are over there please subscribe to my YouTube channel and follow our daily videos as we strive to become self sufficient and off the grid on a budget.

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Troy Reid


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