Boiler won't make temperature!

Re: Boiler won't make temperature!

PostBy: Lightning On: Tue Jan 29, 2013 7:21 am

Thank you for proving my point.. In your example, where did the other 12.5 cubic feet of gas generated heat go??? It wasn't lost, It was absorbed by the surrounding environment that the pot of water is sitting in.
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Boiler won't make temperature!

PostBy: blrman07 On: Tue Jan 29, 2013 7:43 am

I have exactly the same type of discussion with my wife regarding thermostat usage at the church and at the youth centers. The church has an oil air scorcher and the youth center has a gas air scorcher. She thinks that on a very cold day if she puts the thermostat up to 5 degrees higher than normal it will cause the room to be heated quicker. I have spent a lot of time trying to explain that a unit can only put out so much heat at max firing rate and putting the thermostat up higher won't make it fire any faster. It will just run longer to try and get to where the thermostat is set. In order to get those or any other units to heat up faster, you have to change something in the burner setup.

For a coal boiler or stove, it will only burn coal when you have the right amount of combustion air. When the fan is putting out all it can put out, you will max out on the amount of heat supplied from burning coal due to the amount of air being supplied. Want more heat? Either feed more coal or in this case supply more combustion air.

Simple application of supply and demand. Demand more you better supply more of something be it coal or air or both.

Rev. Larry
blrman07
 
Hand Fed Coal Boiler: Bucket a Day
Hand Fed Coal Stove: installing a VC 2310
Coal Size/Type: Pea/Nut/Wood in the VC and anything that will fit in the Bucket a Day. It's not fussy.

Re: Boiler won't make temperature!

PostBy: Rigar On: Tue Jan 29, 2013 7:45 am

But it didnt effectively heat the water...as the water lost heat at a rate in which kept it from boiling
Rigar
 
Hot Air Coal Stoker Furnace: Keystoker A 150
Coal Size/Type: anthracite rice
Stove/Furnace Make: Keystoker
Stove/Furnace Model: A 150 warm air furnace

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Re: Boiler won't make temperature!

PostBy: Rigar On: Tue Jan 29, 2013 7:50 am

Ah...i see your point lightning...
... but I think this is what is going on
buckslayer s boiler "burned" 55 lbs of coal...but not effeciantly...or more accurately...
Not Completely...

if there isnt enough comb air...he may not be getting 13000 btus per pound...or what ever the value may be.
Insufficient air-incomplete burn.....
Rigar
 
Hot Air Coal Stoker Furnace: Keystoker A 150
Coal Size/Type: anthracite rice
Stove/Furnace Make: Keystoker
Stove/Furnace Model: A 150 warm air furnace

Re: Boiler won't make temperature!

PostBy: Berlin On: Tue Jan 29, 2013 8:10 am

A couple of things. First, a boiler should be able to burn at damn close to what it's rated, to not come close is a pretty serious oversight.

Second, It's possible to have a house that size w/ 80,00btu real world loss and more depending on a number of factors.

Third, I think franco has the right idea, but, perhaps, not the most accurate real-world numbers. Start w/ 12,000btu/lb for anthracite and you'll be closer to reality for most coals, then, considering overall efficiency including combustion losses and heat transfer losses, I'd stick w/ 70% fuel utilization or overall efficiency for the appliance, steady state may well be much higher, but with fuel inefficiency at non-full-load conditions and transfer losses, 70% or less would be a better real-world number.

Try 13.5 or 14 lbs for one gallon of heating oil, season average, about 4 to 4-1/2 ton for the season
Berlin
 
Hot Air Coal Stoker Furnace: Will-Burt Combustioneer 77B
Coal Size/Type: Ohio BITUMINOUS pea stoker coal

Re: Boiler won't make temperature!

PostBy: titleist1 On: Tue Jan 29, 2013 8:11 am

Lightning wrote:I don't understand fellas... Franco did the math and determined he should be using around 55 pounds per day based on his oil usage.. Where is the other 45 pounds of heat going?? Into the ash bucket??? Am I blissfully unaware of something lol? None of this explains where the rest of the heat is going... Please enlighten me hahaha

Franco, I just read your hypothesis of the inefficient burning due to the blower on page 4... Would that really make up for 45 extra pounds of coal? That would mean its only getting about a 50% efficient burn rate.


yes it went into the ash bucket as unburned or partially burned coal. the lack of combustion air knocks down the btu's per pound he will get out of his coal because it doesn't burn completely in the amount of time it takes to push it off the grate. the clue to this is that he can only feed coal at about half the max rate or he pushes burning coal off his grate into the ash bucket.

another analogy....there is a bucket that has a couple holes in it that you want to fill with water. the bucket leaks at 2.5 gpm. you have a spigot that can flow 6 gpm you will use to fill the bucket. you only open the valve 1/3 of the way allowing 2 gpm to flow. the bucket never fills up.
titleist1
 
Hot Air Coal Stoker Stove: Harman Mag Stoker (old style) one in basement, one in workshop
Hand Fed Coal Stove: Harman Mark III on standby for long power outages
Coal Size/Type: Rice/Anthracite; Nut/Anthracite

Re: Boiler won't make temperature!

PostBy: Lightning On: Tue Jan 29, 2013 8:21 am

I see the light now, its shining brightly. Thank you, my head was starting to ache hahaha :)

So, when he is burning 100 pounds, at least 40 pounds isn't being burnt. Thats what I'm understanding now...
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Boiler won't make temperature!

PostBy: stoker_RI On: Tue Jan 29, 2013 8:33 am

Rigar wrote:buckslayer s boiler "burned" 55 lbs of coal...but not effeciantly...or more accurately...
Not Completely...

if there isnt enough comb air...he may not be getting 13000 btus per pound...or what ever the value may be.
Insufficient air-incomplete burn.....


Yes..That is what is happening I believe...anaother analogy ( althought not quite the same ) is this: Think of a car that normally gets 20 mpg...obviously it uses 1 gallon over 20 miles. Now lets say its got a severly clogged air filter, which in turn limits the amount of combustion air to be burned along with the gasoline...well the fuel injectors are still supplying the same amount of gas, but now there is not enough air, or oxygen, available for a complete or most efficient burn of the gasoline...so now that 1 gal of gasoline only yields say, 15 miles...same one gallon of fuel, but incomplete burning of it... So same car, with not enough air readily available, suddenly getting 15mpg!

So in the case of gas, that loss of 5mpg, 25%, (wasted unutilized btu's) goes into the air in the form of pollution; in the coal scenario, the unutilized btu's not extracted from the coal due to insufficient available air stays in the rock, but still looks like ash, because its still burned in part, and then ends up in the ash bucket..

I bet if you dumped out the ashes on the ground, over time you would see that the elements have washed clean the ash from the unburned coal, and what previously had looked like a pile of ash would not have more shiny black rock showing...
stoker_RI
 
Stove/Furnace Make: Leisure Line
Stove/Furnace Model: WL 110 Boiler

Re: Boiler won't make temperature!

PostBy: Rigar On: Tue Jan 29, 2013 8:33 am

All in all...the bigger fan should correct the problem (more combustion air)
...but the fact remains that according to LL s own testing for UL....
They ran the boiler "flat out"...for "8 hour shifts "....burning "65 lb of coal"...producing a range of "85k to 101k btu"
Rated efficiency is based on max burn rate...continuously.
Rigar
 
Hot Air Coal Stoker Furnace: Keystoker A 150
Coal Size/Type: anthracite rice
Stove/Furnace Make: Keystoker
Stove/Furnace Model: A 150 warm air furnace

Re: Boiler won't make temperature!

PostBy: Lightning On: Tue Jan 29, 2013 8:39 am

I apologize for the over sight. I was under the impression that his 100 pounds per day was being completely burnt. But apparently, a substantial amount of unburnt coal is being pushed into the ash bucket..
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut Size / White Ash

Re: Boiler won't make temperature!

PostBy: stoker_RI On: Tue Jan 29, 2013 9:06 am

Rigar wrote:...but the fact remains that according to LL s own testing for UL....
They ran the boiler "flat out"...for "8 hour shifts "....burning "65 lb of coal"...producing a range of "85k to 101k btu"
Rated efficiency is based on max burn rate...continuously.


-Apparantly, the test was performed using, I believe, a mechanical draft inducer or the like...this is not a condition that would typically be found in use by a user...so the test to a point, was like apples and oranges, imo....

Leisure Line has said that the manufactured of the Fasco input air blower changed the supplier of the internal components of IT over the last 2 years (which has resulted in a degradation of fan performance in the boiler )...It is possible that the fan used during testing was manufactured before this switch to the internal parts of the fan..
stoker_RI
 
Stove/Furnace Make: Leisure Line
Stove/Furnace Model: WL 110 Boiler

Re: Boiler won't make temperature!

PostBy: plumber On: Tue Jan 29, 2013 10:00 am

Even if the 100 lbs was being completely burned, that would only yield 50-55,000 btu/h. If his heat load is 80,000, he is negative 25-30,000 btu. The boiler will burn coal, but as the house is losing more heat than is being generated the boiler will run flat out for nothing.
plumber
 
Stoker Coal Boiler: EFM 350

Re: Boiler won't make temperature!

PostBy: Rigar On: Tue Jan 29, 2013 10:14 am

plumber wrote:Even if the 100 lbs was being completely burned, that would only yield 50-55,000 btu/h. If his heat load is 80,000, he is negative 25-30,000 btu. The boiler will burn coal, but as the house is losing more heat than is being generated the boiler will run flat out for nothing.


.. exactly!
I guess that was my point earlier...
if flat out burning only produced on average BTU output of approximately 100k btu or so...
and his heat loss is 80k btu... is the boiler in fact under sized??
.. as it would have to run ALMOST flat out to keep up?
Rigar
 
Hot Air Coal Stoker Furnace: Keystoker A 150
Coal Size/Type: anthracite rice
Stove/Furnace Make: Keystoker
Stove/Furnace Model: A 150 warm air furnace

Re: Boiler won't make temperature!

PostBy: plumber On: Tue Jan 29, 2013 10:24 am

If the boiler was generating 100,000 btu/h output, he'd have a net gain of 20,000 btu/h. That being the case, he'd have a warm house and the boiler would be cycling.
plumber
 
Stoker Coal Boiler: EFM 350

Re: Boiler won't make temperature!

PostBy: SteveZee On: Tue Jan 29, 2013 10:31 am

Lightning wrote:I apologize for the over sight. I was under the impression that his 100 pounds per day was being completely burnt. But apparently, a substantial amount of unburnt coal is being pushed into the ash bucket..


I simply read as an efficiency problem due to the lack of proper air. Instead of the 80% assumtion he's only getting 40-50% for the load. Because the time is a constant (feed rate), it has to unburned or unused fuel. (notice I said simply) ;)
SteveZee
 
Hand Fed Coal Stove: Glenwood Modern Oak 116 & Glenwood 208 C Range

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