I own the Aspen 175 and live in Maine and began using it in mid january. I am working out a few problems but i do like the unit. During the 4 week period from mid january to mid february i used 1.5 cords of wood, this was a colder than normal month well below 0 many nights. I am heating a 3100 square foot house which includes a 600 square foot garage with 10' high ceilings. I am also heating my hot water. once the temp gets into the 30's the wood usage goes down. I estimate that i will use 6 cords of wood to heat my house and provide me hot water from November to May. I have kept track of every time i have loaded wood, what the weather was and how much wood i went through from week to week. During the coldest times of the winter i got a 12 hour burn time and once it's close to 40 degrees outside i get close to 24 hours. I used 1 1/4" pex buried 30 - 36" deep. Each line i insulated with 3/4" wall thickness foam and then wrapped with one layer of reflextix(looks like bubble wrap 1/4" thick). I then put each line in its own schedule 35, 4" pipe. For good measure i put a 2' wide sheet of 2" rigid insulation on top of that. I have the boiler 75' from my house.
My wife is in the health field so it was very important to have a clean buring unit.
A few problems i have had are that the unit tends to drip a small amount of condensation in the front of the aspen during certain temps and i do from time to time get a bit of brown like condenstation on the foof of the boiler from the chimney. I believe this may be because the low stack temps along with dew point. You wouldnt see this in an older style wood boiler as much because the stack temps are higher. but that also means you will burn more wood and pollute more.
Freeze protection: My system has a 30% glycol solution giving me a low burst point. One good thing about the aspen is it only uses 75 gallons of water plus whats in the pex and it only costs a little over $200 to glycol the system. I believe this system has the lowest amount of water. It would cost a lot more to glycol most other systems.
My system also is isolated from my heating system using a heat exchanger. I believe this is important because the aspen like most or all outdoor wood boilers is an open loop system and hooking them directly to a closed loop system is not a good idea in my opinion. Because of this i have an aquastst that shuts the wood boiler circulator off if the water goes below 140 degrees. If the circualtor didn't shut off the oil burner it would heat the wood boiler water through the heat exchanger wasting oil. I also have a low temp aquastat on the wood boiler that turns the wood boiler circulator back on if the water drops below 35 degrees. This aquastat keeps the water between 35 and 45 degrees to further protect the system. I can now leave my house whenever for any lenghth of time without worry and without burning a bunch of oil to keep my house and wood boiler heated.
You also need a dump zone to keep the boiler from boiling over, my dump done has only come on a few times, less as i get better at understanding the wood loading part of things.
I would love to hear from other aspen owners.
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Topic: Consider An Aspen OWB (Read 3488 times)