Any ideas on how to increase burn time on this bad boy? I've been reading online and it appears that most folks get 2-3 hours with split wood, 4 hours or so with unsplit rounds...I'd like to at least get 6-8 hours so I can get an overnight burn without the oil kicking in. If I can't, oh well, it's a freebie, but still it would be nice.
I have a couple thoughts though. It only has a 17" wide x 21" tall firebox at 22" tall...seems small compared to newer units. This one was made in May of 1978. Maybe thats all we can get is 4 hours out of it?
My second thought is that it only has a 50 gallon water jacket, seems most units now have 150-200 as a minimum. Maybe I could add a hot water storage tank to it and even though it would only actually burn for 4 hours, I would have heat for 8?
My house has a design btu draw of 40,000btu/hr, so on average it would be half that. If I want 4 hours of 20,000btu/hr, I would need 80,000btu/hr storage. With a 20 degree delta T, running the storage tank at 160/180, that would mean I would need a 500 gallon tank. My basement isn't super large, and storage tanks are kinda pricey, so I'm not exactly fond of that option. I could go with an old 30 gallon water heater, which would give me an amazing 4,800btu/hr of backup...aka - a little less than 15 minutes of heat after the fire goes out.
Couple other ideas, I'm not including the 50 gallons IN the boiler jacket, so that would give me 40 minutes of heat after the fire goes out if I add the 30 gallon tank, call it 30 minutes if it's super cold out. AND the oil will kick in if the fire runs out, so it's not like I'd be without heat. I could set a little beeper to alert me when the temp in the boiler drops below say...150F or so. Wake up and feed the boiler at night.
Or for now we could just stoke it at night, let it go out and have the oil kick in during the early morning hours till we wake up. We'd still save a lot of oil and for now it would be "ok." Eventually we will upgrade the boiler anyway, and maybe we could add a 500+ gallon heat storage tank at some point.
I now get why outdoor wood boilers make so many folks happy with their giant fireboxes and 200 gallon (32,000btu/hr) water jackets as heat reserve.