Boiler won't make temperature!

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.

But it didnt effectively heat the water...as the water lost heat at a rate in which kept it from boiling

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.....

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

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.

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...

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...

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.

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..

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..

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 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?

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.