Re: Dang it is cold, and getting colder
I have been thinking of a boiler for the last couple of years, neighbour has one but he"s starting to get pin holes in his boiler jacket, (do you ever check the PH balance like we do in the diesel engines to avoid pinholes in the sleeves?) anyways would be nice to heat the shop and house, to late for the in slab but could always dig up those old cast iron rads from the schools they"ve pulled down.
The "modern" outdoor boilers are open to the atmosphere, and they take in oxygen from the atmosphere which will corrode it and other iron parts in the system from the inside. There are testing systems and additives that can control this, but just like battery maintenance it has to be kept up religiously.
I use a pressurized boiler from the 1980's. They are not open to the outside, and you cannot use pex with them because pex derates to zero at 212 degrees, and will actually break all by itself at higher temperatures. It has to do with the cross linking characteristics. It's filled with a propylene glycol and water anti-freeze to about -15F, and a boiler water conditioner/anti-leak additive. It's pressurized to 10 lbs cold, and runs about 15 lbs hot. The overtemp emergency system gets excited if it gets to 240 degrees. It normally runs between 190 and 220 in extreme weather.
I have a 15 x 15 woodshed with a 15 x 8 boiler room attached. The cat gains access through the combustion air supply, or maybe the combustion air comes through the cat door. Anyway, everybody is happy.
I like a pressurized system. Once set up, maintenance is very low. The entire system, including the boiler, a couple hundred feet of line, and radiation, only holds thirty and a couple gallons of water. It would be pretty expensive to put propylene glycol into a system that holds a couple of hundred gallons of water.
There are quite a few of the old wood boilers still around. The dry back ones pretty much self destructed, but the wet back ones should be in good shape. Even if you find one that's been abused and needs a little welding, it would be worth it. There are some cast iron ones around, like Buderus, also.
Kewanee, Hurst, and others.
BTW, I anybody is thinking of installing a presurized system, I can help. I was the design engineer at WoodHeaters of Minnesota back during the Arab Oil Embargo. I supported about a hundred small dealers installing air and hydronic systems, including hybrid systems, multifuel systems, and campus systems. While there, I did the ASME engineering, control design, and manuals for one of the manufacturer's wood boilers.
