Boiler Won't Make Temperature!

Its not heat loss guys...its the fact that the stock air supply fan on the boiler has proven to be insufficient..so this is causing the boiler to put out much less BTU's than was expected...this is in this post from Leisure Line...there are many of us with the same boiler having the same issues and getting the same results...LL has promised to send out replacement blowers this week...so after that retro-fit we can re-asses..lets hope it works! We all want to see the boiler perform as promised and see all parties content ...and warm!

Rigar wrote:Buckslayer cant burn any more coal if he wanted to...it would drop into the ash pan ?

Yes because the inadequate combustion air supply can't support burning coal any faster.

If we were to take a big boiler burning 2 gallons an hour of oil and change the nozzle to 1 gallon per hour and were able to adjust the burner so it burned well, it probably would run constantly and never get up steam or if hot water generate enough heat to reach the point that the reverse aquastat would allow circulation. We would burn 24 gallons in the 24 hours and get no heat where it counted.

By old school calculations of 6 btus per cubic foot assuming he has 8 ft ceilings, 80,000 is about right. Heck, when I went to school heat loss was as simple as x BTU per cubic foot. Usually 5 on a tight house 6 on a loose house and 5.5 inbetween.
Also, a boiler that is never satisfied will chew threw as much fuel as you can feed it. If he's burning 100lbs a day and his heat loss is 80,000, he is losing 15,000 BTU per hour. At that rate the boiler will never shut off! The same would happen if he had a .60 nozzle on a oil gun. He'd burn through 15 gallons of oil and be cold.

franco b wrote:

Rigar wrote:Buckslayer cant burn any more coal if he wanted to...it would drop into the ash pan ?

Yes because the inadequate combustion air supply can't support burning coal any faster.

If we were to take a big boiler burning 2 gallons an hour of oil and change the nozzle to 1 gallon per hour and were able to adjust the burner so it burned well, it probably would run constantly and never get up steam or if hot water generate enough heat to reach the point that the reverse aquastat would allow circulation. We would burn 24 gallons in the 24 hours and get no heat where it counted.

Beat me to it!

plumber wrote:

franco b wrote: Yes because the inadequate combustion air supply can't support burning coal any faster.

If we were to take a big boiler burning 2 gallons an hour of oil and change the nozzle to 1 gallon per hour and were able to adjust the burner so it burned well, it probably would run constantly and never get up steam or if hot water generate enough heat to reach the point that the reverse aquastat would allow circulation. We would burn 24 gallons in the 24 hours and get no heat where it counted.

Beat me to it!

Great minds think alike

... yes great minds do think alike!
... so I must not be of great mind..!!
..lol.. but seriously.. I understand the whole fuel per hour concept... but I must of mis understood Franco's explanation comparing fuel oil usage to coal usage?
... I took it as compared to his fuel oil usage.. he was on par for the amount of coal he was burning?
did I misunderstand that..?
my logic was that based on his oil usage compare to his coal usage... even the oil fired boiler could not have been keeping up( or at least had trouble keeping up in this cold weather)
... I cannot imagine any coal fired boiler rated it over 100000 btus or more could have any trouble burning 10 pounds an hour...imo

The 80,000 BTU heat lose still has me stumped.
Even with a smooth curve from fall to spring,
that's a lot of oil or coal.

tsb wrote:The 80,000 BTU heat lose still has me stumped.
Even with a smooth curve from fall to spring,
that's a lot of oil or coal.

...and yes...that seems substantial

It was meant to compare buckslayer's coal consumption with his previous oil consumption.

Knowing the BTU value of the coal you are using, you can compare easily to oil. To predict what you will burn you need the number of degree days for your area. The example I used was for my area (not knowing his location) and that perhaps was confusing.

To feed and burn 10 pounds an hour you need enough air to do it. Like trying to load a small stove faster than it can burn the coal. At some point it will come out the door or with a carpet bed stoker pushed over the edge.

franco b wrote:It was meant to compare buckslayer's coal consumption with his previous oil consumption.

Knowing the BTU value of the coal you are using, you can compare easily to oil. To predict what you will burn you need the number of degree days for your area. The example I used was for my area (not knowing his location) and that perhaps was confusing.

To feed and burn 10 pounds an hour you need enough air to do it. Like trying to load a small stove faster than it can burn the coal. At some point it will come out the door or with a carpet bed stoker pushed over the edge.

...gotcha.
I thought the degree day numbers were for him...my bad.
If indeed his heat loss is 80000 btu...is his boiler big enough in your oppinoin?

franco b wrote:It was meant to compare buckslayer's coal consumption with his previous oil consumption.

Knowing the BTU value of the coal you are using, you can compare easily to oil. To predict what you will burn you need the number of degree days for your area. The example I used was for my area (not knowing his location) and that perhaps was confusing.

To feed and burn 10 pounds an hour you need enough air to do it. Like trying to load a small stove faster than it can burn the coal. At some point it will come out the door or with a carpet bed stoker pushed over the edge.

The difference you see with the new blower is a much taller and bluer hotter flame. My coal consumption seems to be down by 1/2 bag or more 24 hr period. It is hard to tell because it is 20* warmer. But I went from 3 bags to 2 . Ash is finer and better burned. I did get 2 of the blowers in today, I installed one on my way home, he was impressed how fast it was getting up to temp. Big house 4 zones. It was 130 when I got there. I left when it got to 160 after replacing the blower. The other blower is going to #1 on my list. So yes Don you should have it Wed.
I set the base pressure to .02 and the pipe draft to .04 -.05 . The rheostat will have to be adjusted for idle when the weather warms. But I am convinced this is the issue and the new blower resolves it.


I am sitting back here reading some of the thought process that is put into burning little rocks. I have to say I am getting a little chuckle. I wonder if the oil guys ever chatted like this?

Rigar wrote:If indeed his heat loss is 80000 btu...is his boiler big enough in your oppinoin?

The heat loss calculation is usually made to provide enough heat when the local weather is at the lowest expected temperature for that location. From that you decide on the right size boiler. In NYC you would figure a big enough boiler to provide enough heat when the temperature was zero. In Maine you would have to size the boiler for below zero weather.

So the 80,000 figure is only for the coldest temperature for that region. Yes the boiler is big enough once it is firing properly and can get up to the output it did on testing when needed.

Flyer5 wrote:I am sitting back here reading some of the thought process that is put into burning little rocks. I have to say I am getting a little chuckle. I wonder if the oil guys ever chatted like this?

Yes they sure did and it was at the supply houses over free coffee where it happened. Some companies would have as many as 20 service men and the few that were really good answered the questions. The oil truck drivers were alone all day and they chattered like a room full of women when they came in at the end of the day.

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.

Ok, let's put it this way.

Put a large pot of water on your stove and turn it all the way up. Lets say that burner is 30,000 btu. That pot of water boils in 5 minutes. You accomplishes your goal with 2.5 cubic feet of gas.
Now put the same cold water on the stove and put the flame on half way. An hour later you still have just warm water, and you burned 15 cubic feet of gas.