Outdoor Wood Furnace Info
Outdoor Furnaces - Manufacturers with NON EPA-Certified Models Only => Shaver Furnace => Topic started by: NCredneck on March 29, 2011, 06:23:14 AM
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I know this is not a shaver but so close its gotta be a design copy. My question is ...Has anyone got one..like it or not?
or Has anyone looked at one and been thinking bout buying one. I just wonder if they improved it by putting a fan mod on it and a better temp gauge.....no site glass or anything for water just fill it once a day until it pees out the side.
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Ok, just got off the phone with a Earth dealer. He said they got a mechanical damper which aint ideal. On the plus side, said the fire box and the water box was 1/2 inch. Thats very good. Door that looks like a shaver is adjustable, also good.
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Thickness of the firebox has a trade-off, there is a decline in heat transfer as the steel increases. I saw one of the manufacturers had a model 'certified' for the thinner firebox but not the thicker option. Maybe it was just an 'economic decision' not to go for the certification. You ask 'where does the heat go that doesn't go thru the firebox and heat the water to 180?' It goes up the stack or thru the front door of course. The fire on the inside is 500 plus while the thermostat shuts off the blower at 180 water temperature. That 300 degree temperature gradient across the steel does not instantly go into the water. Taken to its illogical extreme, if the firebox was 6" thick where would the heat be going?
Seems to me that we have very robust OWB's with 1/2" fireboxes that lack efficiency, then we can go to the gassifiers which have some technical risks and are very efficient. In between we have some classic designs with 3/16-1/4" fireboxes.
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rhugg, guess it would all boil down (punn intended) to temp and velocity of air coming outta the stack. I do believe you can go too big but is 1/2 inch it.....I don't know. I sorta like the idea of having some meat there to weld to if it does spring a leak in 8 to 12 years and maybe all that metal would be a big ol heat sink so it cycles less often burns just as good...again I don't know. Guess I a tool man taylor type and when I see 1/2 inch...I go umphh umppphhh umphhh...lol :D
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I agree with rhugg, the thicker they are the less efficient. This has been proven in testing by a number of companies. If I was looking for a mild steel furnace I would want one where the water jacket is much thicker then the fire box. Water jackets are where they often leak anyway and the thicker they are the less heat you lose to the great outdoors.
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Hey Yoder- I guess I would have to disagree with you(respectfully,of course) about wall thickness. When the majority of these boilers start leaking,they tend to leak into the firebox from the boiler. If one had to be a little thicker than the other, I guess I would prefer that the combustion chamber be a bit thicker. Welding on the outside of a boiler is much easier than the inside of a baffled firebox. I think a quarter inch fire box is about perfect, and I would think one could easily get by with 3/16 boiler- as long as the water quality is kept in check. The CB that I seen back in December had rusted through the firebox and into the boiler. I believe they know what they're talking about when they tell you to thoroughly clean the firebox out and make sure and put a bucket over the exhaust(water plus ashes makes a great metal acid etcher). After all the water ran out,they poked the hole out much larger, thinking they might be able to patch it, and shined a flashlight in and looked at the boiler wall bottom. After 9 full seasons the inside of the boiler looked new. That's my .02 anyway.
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Well, now I agree with you about the ash and water problems. But the ones I've seen that rusted through at the firebox, almost all could have been prevented if the owner had kept the fire box cleaner and dryer (not trying to say this was your problem). The reason I worry about the water jacket is because you can't see the sediment build up that causes the corrosion.
You do bring up a very good point, keeping a furnace clean will add many years to its life. This would include flushing the system every few years as well to remove any sediment build up in the tank.