Outdoor Wood Furnace Info
All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: clydem on January 05, 2018, 10:49:38 PM
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Is anyone in Michigan experiencing short burn times per load?
For the last 2-1/2 weeks overnight temps average +5 to -22 daytime ave +15* to +20*
This is the first time in 8 winters I have went from 12hr burn times to 8 hours between loads. I have my CB5036 temp set @185* and my monitor system emails me if the water temp hits 168*.
Is it just the low temps & the higher home heat load causing the 30% drop in burn times? :bash: What do you think?
Water level ok
door gasket new in Oct 17
well seasoned ash, oak & maple
damper clean & working fine
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These last 2 weeks are the hardest my G200 has run since I installed it. I am very pleased with its performance and I can still get 12 hour burn times at night, 14 if I push it but that is filling it almost full. About half loads during the day.
My temps cycle from 180 to 160 (factory preset) and been working good for me.
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I have a guess ready stoves needs a good clean out .or test your trench lines at boiler and in house should be same temp maybe loosing 1-2 degrees depending on line length . Sounds basic but that's first things to think about .
at below 0f it can be alot of factors . wind , wood moisture house pulling more heat.
Heat550
I don't see a draft fan on your model . So clean stove would be more of a issue .
Is anyone in Michigan experiencing short burn times per load?
For the last 2-1/2 weeks overnight temps average +5 to -22 daytime ave +15* to +20*
This is the first time in 8 winters I have went from 12hr burn times to 8 hours between loads. I have my CB5036 temp set @185* and my monitor system emails me if the water temp hits 168*.
Is it just the low temps & the higher home heat load causing the 30% drop in burn times? :bash: What do you think?
Water level ok
door gasket new in Oct 17
well seasoned ash, oak & maple
damper clean & working fine
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I live in the upper Penninsula and it has been -5 for a high and -30 at night, with some windy days. I have been coming home from work to hot coals and a boiler at 155 or so, after a 11 hour burn time. I would say a 8 hour burn time is probably what I am getting in this cold snap as well. Worst it has been in the last 4 years for me.
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I'm seeing the same thing here in SE Ohio with my 6048. I've monitored and recorded temperatures on mine for the past 5 years and have noticed my delta t has increased some this year for some unknown reason. I'm seeing the return temperatures from two baseboard heaters 20 to 30 degrees hotter this year than in the past. cleaned the dust out of them and it didn't change anything. I'm thinking I need to look in the attic and see if the insulation is gone!
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Unless all your structures are very well insulated extreme cold with any amount of wind will raise the heat load which will shorten burn times.
I got called out awhile back, installed a used Woodmaster 434 for a young couple, wasn’t running continuously but couldn’t get the house over 62, up until then it did fine, but set records that night, low turned out to be -14 with a windchill of -30, turned the cutout up to 192 and tightened the differential up, had the house up to 69 by morning, I can guarantee that killed his burn times.
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If you need to warm your house from 25 degrees to 70 degrees that means you need to raise it 45 degrees. If you need to raise it from -15 to 70 that is 85 degrees. Double the heat, double the wood. It is simple math.
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I used to run a Cozeburn MS250 that was similar in design to a 5036, with a draft fan in the door. I don't recall having one of these 3 week below zero spells like we're having now when I had it, but I do know any single day below zero would flatten that poor thing in 6-8 hours. I could fill it full enough that I'd have to hammer another toothpick in it and still only 6-8 hours. It was undersized for me of course, but subzero temps are going to cause an excessive hunger problem with any boiler
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Ya, its probably just be the cold. Subzero temps always seem to do a number on the wood pile. I did some heat loss calculations on my home and shop a few years back and IIRC, -25 required like 2 1\2 times more BTU's then 20 above to maintain the same indoor temperature. That means 2 1\2 times more wood.
Once temps moderate next week things should get back to normal.
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If you need to warm your house from 25 degrees to 70 degrees that means you need to raise it 45 degrees. If you need to raise it from -15 to 70 that is 85 degrees. Double the heat, double the wood. It is simple math.
I see what your trying to say but I'll have to disagree on the double the wood. My stove actually burns better and same or a smidge less wood when it starts to get around 0 compared to 25-35 unless it is real windy. I relate this to the short on off cycles and being able to burn more efficient. This has been my experience with my portage and Maine and was not the case with my ridgewood 6000 I had.
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Some models seem to run better with a heavy load, others not so much.
We've gotten more calls about record wood consumption in the last couple of weeks than I can remember for a long time.
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yes with these fridge cold temps I'm definitely getting a shorter burn time..I got plenty of wood though!
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One other thing your daft is drawing twice as much also
Cold heavy air . At below 0f my slabs startburning just when
They get inside the boiler door it's like below 0f makes it draw dang hard. There's no flames but it's so hot slabs ignite instantly air so hot. I have 300 cfm blowers.
Heat550
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all things mentioned above are valid factors, however at the amount your referring too. Wet wood can effect burn times that much that dramatically. I would look for a major problem in the system, or use the moisture meter to truly find out wood conditions.. Even good seasoned wood can absorb water depending on storage conditions.
well covered and aged wood, off the ground....
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First of all thanks for all who have replied... Having worked in a power plant I understand how having pre-heated combustion air would raise the efficiency of the boiler, I just haven't figured how to capture wast heat from the chimney & pipe it to the draft intake. Any ideas?
One of these days I'll have to quit overthinking this stuff.
thanks again & Keep Warm
Clyde
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If you look at the combustion air path of the G series it actually does some preheating of the combustion air. The air is drawn through the bottom of the rear of the stove which is quite warm then through a baffle which passes the air next to the heated boiler inside of the jacket insulation before taking it to the inlet damper. Not sure how much it is heated but it sure has to help.
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Btu needs of a home change as temperatures drop or rise and wind changes. The btu needs of a house double if you need to raise the temp 50 degrees instead of 25 degrees. Whether or not some boilers operate a little more efficiently depending on outside temps doesn’t change the fact that the actual btus needed does double.
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Point Blank nailed this one. Extra frigid cold temps or high winds will raise the amount of btu your house or other buildings being heated need. Does not matter it you are burning wood, propane, heating oil or electricity, your furnace will will run more often and burn more energy. Don't waste your time looking for something wrong with your OWF. It's just cold and your house is hungrier.
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I agree. If it didn't burn more wood when the weather is colder then I would be looking for problems with why it is burning so much when it is warmer.
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Both my boilers burned better the colder it got .
But when you reach point when outside temp is 100 degrees
Colder then inside temp . Your boiler will burn wood like it's never
Burned before. Being that cold it will work it's way into any building.
In 12 hours the night it got to -21f I burned 400 lbs oak slabs .
Heat550
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I agree. If it didn't burn more wood when the weather is colder then I would be looking for problems with why it is burning so much when it is warmer.
:post: