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1
Natures Comfort / Fuel for thought
« on: January 29, 2015, 06:45:27 AM »
Just brought a new 325G online. First brought the in law apt (where we live) online 2 weeks ago
then the main house (where son & wife live) on last week. A question on another NC thread about
how often a 400G is loaded inspired this posting.
My brother questioned how much wood we're burning. He claims his buddy only adds about 6
pieces of wood twice a day to his CB boiler to heat his 3000 sq ft home with DHW. I visited the
fellow last summer. He buys unseasoned wood in the fall for the winter so I suspect the story
is not quite complete.
So I did some calculations and would appreciate any feedback. Here they are:
One cord of seasoned red oak: 24.6 million btu/cord
2000 sq ft home, 8' ceilings: 60000 to 80000 btu/hr (using 30 to 40 btu/sq ft)
DHW 30000 - 50000 btu/hr (estimates reviewing several heating sites for sizing hot water heat)
therefore consumption should range from a low of 2.16 million btu/day to 3.12 million btu/day
net consumption would be a high of 11.4 days/cord to low of 7.9 days/cord
We are heating more than double the example as we also heat a 1000 sq ft basement
and a 900 sq ft garage though these would have much smaller heat differentials.
We are seeing not surprisingly about 4 to 5 days/cord
Some known errors:
Boilers are probably 75-80% efficient so consumption would be higher
DHW shouldn't be 24 hr/day so consumption should be lower
btu/hr numbers are based on heating to 70 degrees in 20 degree weather
we've seen single digit nights recently so consumption will be higher
Our loading experience using mostly oak split 18 - 21" originally for inside wood burners
tossing into boiler results in loosely full load, next wood will be cut longer and split less
a single digit night will burn a loose full load in 6-7 hrs
20 degree night with 30 degree day can be loaded just once in morning and once in
the evening.
Any thoughts
then the main house (where son & wife live) on last week. A question on another NC thread about
how often a 400G is loaded inspired this posting.
My brother questioned how much wood we're burning. He claims his buddy only adds about 6
pieces of wood twice a day to his CB boiler to heat his 3000 sq ft home with DHW. I visited the
fellow last summer. He buys unseasoned wood in the fall for the winter so I suspect the story
is not quite complete.
So I did some calculations and would appreciate any feedback. Here they are:
One cord of seasoned red oak: 24.6 million btu/cord
2000 sq ft home, 8' ceilings: 60000 to 80000 btu/hr (using 30 to 40 btu/sq ft)
DHW 30000 - 50000 btu/hr (estimates reviewing several heating sites for sizing hot water heat)
therefore consumption should range from a low of 2.16 million btu/day to 3.12 million btu/day
net consumption would be a high of 11.4 days/cord to low of 7.9 days/cord
We are heating more than double the example as we also heat a 1000 sq ft basement
and a 900 sq ft garage though these would have much smaller heat differentials.
We are seeing not surprisingly about 4 to 5 days/cord
Some known errors:
Boilers are probably 75-80% efficient so consumption would be higher
DHW shouldn't be 24 hr/day so consumption should be lower
btu/hr numbers are based on heating to 70 degrees in 20 degree weather
we've seen single digit nights recently so consumption will be higher
Our loading experience using mostly oak split 18 - 21" originally for inside wood burners
tossing into boiler results in loosely full load, next wood will be cut longer and split less
a single digit night will burn a loose full load in 6-7 hrs
20 degree night with 30 degree day can be loaded just once in morning and once in
the evening.
Any thoughts
2
Portage & Main / 2 Year old 250's
« on: April 29, 2014, 02:35:40 PM »
We're still looking to install an Optimizer 250 this summer. Came across a dealer near where we live
who has 2 sitting on his lot. The plate inside says they were made in Feb 2012, though the rep said
they were 2013's. Does anyone know of any reason to be cautious about offering to buy on of them.
The dealer apparently did not cover the chimney and they are sitting outside. I noticed one had
rust on all the tube ends, the boxes stored in the back were water stained and the brushes rusty.
The other one seemed to have fared better. They both had brick slots. Do I understand the new
ones have steel? You input is appreciated.
who has 2 sitting on his lot. The plate inside says they were made in Feb 2012, though the rep said
they were 2013's. Does anyone know of any reason to be cautious about offering to buy on of them.
The dealer apparently did not cover the chimney and they are sitting outside. I noticed one had
rust on all the tube ends, the boxes stored in the back were water stained and the brushes rusty.
The other one seemed to have fared better. They both had brick slots. Do I understand the new
ones have steel? You input is appreciated.
3
Portage & Main / Firebox size
« on: April 26, 2014, 05:36:17 AM »
Just a light question, probably for slimjim, the P&M consultant
The Optimizer specs say the firebox (or firepot) size is 28' x 30" x 30" or 11 cu ft.
Isn't a cu ft = 12 x 12 x 12 cu in or 1728 cu in?
28 x 30 x 30 = 25,200 and 25,200 / 1728 = 14.6 cu ft
Are the dimensions nominal and the volume precise or vice versa?
Or are these Canadian inches?
The Optimizer specs say the firebox (or firepot) size is 28' x 30" x 30" or 11 cu ft.
Isn't a cu ft = 12 x 12 x 12 cu in or 1728 cu in?
28 x 30 x 30 = 25,200 and 25,200 / 1728 = 14.6 cu ft
Are the dimensions nominal and the volume precise or vice versa?
Or are these Canadian inches?
4
Portage & Main / Distance from house
« on: April 25, 2014, 09:19:05 AM »
Imposing on you all again for some pre purchase input. This time on distance from house to OWB. We've only been considering the P&M 250 vs
CB 1450/2400. Our concern is placement. The P & M dealer said 25 ft away is minimal and he prefers 35 ft. The CB dealer called the
manufacturer and checked the regs and said only 4 ft is needed. Given our terrain, this makes a difference. We can adjust for the old
chimney rule of 3 ft higher than any roof within 10 ft though the CB dealer says given the FD fan, this is not an issue. Prevailing wind, BTW,
is away from the house in all locations. Can't believe it's manufacturer dependent, but we could be wrong. (We also realize insurance may
play a part).
CB 1450/2400. Our concern is placement. The P & M dealer said 25 ft away is minimal and he prefers 35 ft. The CB dealer called the
manufacturer and checked the regs and said only 4 ft is needed. Given our terrain, this makes a difference. We can adjust for the old
chimney rule of 3 ft higher than any roof within 10 ft though the CB dealer says given the FD fan, this is not an issue. Prevailing wind, BTW,
is away from the house in all locations. Can't believe it's manufacturer dependent, but we could be wrong. (We also realize insurance may
play a part).
5
Portage & Main / Western PA, BL versus Optimizer, 250 vs 350
« on: April 20, 2014, 09:30:23 PM »
I'm new to owb. After initial research am leaning toward P&M. Local dealer is throwing my son and I a curve. We wanted a gasser, e.g. the 250. The dealer is pushing the BL configured for coal because first it avoids the EPA problem in PA and second because coal is cheap and abundant here. His pitch is that gassers
are too finicky and we'll end up frustrated. He stocks the BL's but will order a 250 if we want. After reviewing most of these threads back to January, it seems
the problems are mostly the learning curve and a few technical issues that P &M (and slimjim) help you address. We're not completely opposed to the BL but
are under the impression the 250 will be more efficient and slightly carbon friendlier. We've used wood indoor in a German Weso for almost 20 years. Never cut
a live tree. The gypsy moth left enough red oak silver ghosts on our property to never need to cut living trees. Dry wood will not be a problem. Are there other
drawbacks to using a coal boiler for primarily wood?
The second question is sizing. When he scared us about excessive tube maintenance, we looked at CB Eclassics. Their 1450 seemed about the right size. Based
on the EPA ratings it seemed about midway between the 250 and 350. We're intending to heat a double English Tudor brick home built in 91. It has a 2100 sq ft
main house and a 1200 sq ft in law apartment separated by a 3 car garage. Both have forced air heat pump systems to which exchanges would be added. In the
main house a 1200 sq ft basement needs to be added. A 350 sq ft office is being added above the garage. The apartment has a 400 sq ft enclosed porch to be
added. The additions will probably get fin tube or cast iron baseboards. Plus 2 water heaters will have exchangers added. We're located at an altitude of 2000
ft. Does this sound like too much for much for a 250 (which already prices in about $2K more than the CB 1450). We understand that published numbers are at
best estimates and would appreciate some real world input. Thanks in advance for any guidance you can give. Our timetable is this summer.
are too finicky and we'll end up frustrated. He stocks the BL's but will order a 250 if we want. After reviewing most of these threads back to January, it seems
the problems are mostly the learning curve and a few technical issues that P &M (and slimjim) help you address. We're not completely opposed to the BL but
are under the impression the 250 will be more efficient and slightly carbon friendlier. We've used wood indoor in a German Weso for almost 20 years. Never cut
a live tree. The gypsy moth left enough red oak silver ghosts on our property to never need to cut living trees. Dry wood will not be a problem. Are there other
drawbacks to using a coal boiler for primarily wood?
The second question is sizing. When he scared us about excessive tube maintenance, we looked at CB Eclassics. Their 1450 seemed about the right size. Based
on the EPA ratings it seemed about midway between the 250 and 350. We're intending to heat a double English Tudor brick home built in 91. It has a 2100 sq ft
main house and a 1200 sq ft in law apartment separated by a 3 car garage. Both have forced air heat pump systems to which exchanges would be added. In the
main house a 1200 sq ft basement needs to be added. A 350 sq ft office is being added above the garage. The apartment has a 400 sq ft enclosed porch to be
added. The additions will probably get fin tube or cast iron baseboards. Plus 2 water heaters will have exchangers added. We're located at an altitude of 2000
ft. Does this sound like too much for much for a 250 (which already prices in about $2K more than the CB 1450). We understand that published numbers are at
best estimates and would appreciate some real world input. Thanks in advance for any guidance you can give. Our timetable is this summer.
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