Oil fired boiler question


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Old 01-29-08, 01:36 PM
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Oil fired boiler question

I recently purchased a new, but older looking boiler unit. The only markings are on the gun. It is a Volcanoil from Montreal and is 300,000 btu.
Does anyone have any information about this boiler? I realize that it is probably twice the size I need to heat my 1120sq. ft home in northern Canada, but could it be used and modified to work relatively efficiently?
Thanks
Mike
 
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Old 01-29-08, 01:40 PM
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Id say even that far north 300K BTU is to much for 1120sq ft. . Id say its to big to try and cut down the input on it.
 
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Old 01-29-08, 01:53 PM
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You'd be wasting your money... that's probably over 6x oversized for what you need. Severely under-firing a boiler as you suggest would mean that that heated gases barely even need to affect the walls of the inner passages where they exchange heat as the gases leave the boiler to ultimately go up the flue (along with your dollars).
 
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Old 01-31-08, 11:15 AM
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What about reducing the nozzle size. If I were to drop the nozzle size to about 1.0 gph, won't the result be lowered BTUs and thereby making it work more efficiently?
 
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Old 01-31-08, 11:22 AM
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Yes you can put a smaller nozzle in it . BUT LIKE SAID. IT WONT WORK. the boiler is to big.
 
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Old 01-31-08, 12:40 PM
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Too some degree you need enough gases to fill up the internal passageways to get heat transfer. With large passageways and a small volume and flow of hot gases it might not hardly heat up any water at all before going out the chimney.

Got a few neighbours that you could run pipes to and create a small district heating system?
 
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Old 01-31-08, 01:02 PM
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Originally Posted by Yamahammer View Post
What about reducing the nozzle size. If I were to drop the nozzle size to about 1.0 gph, won't the result be lowered BTUs and thereby making it work more efficiently?
You can only down fire to the specs provided
by the manufacturer for your boiler. Permissible
down fire rates are usually VERY minimal,
from what I've read.

Pete
 
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Old 01-31-08, 08:45 PM
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smaller nozzles

you did'nt say what size nozzle was in it now? I'm firing a boiler on a 1 gph nozzle and the boiler calls for a 1.35. you can drop nozzle size to some degree. but keep in mind the burner will run longer to produce the heat needed to satisfy the thermostat.
 
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Old 02-01-08, 03:17 AM
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In boiler design there is a certain amount of fire side heating surface for a btu input. You can only change that input by 20% max if it's in the design. Reducing the nozzle size is going to kill the AFUE and will not be efficient at all. It is a common mistake in thinking reducing a firing rate is more efficient. It becomes less efficient when looking at the over all operation for the whole season. If you fire to capacity you are filling the flue passes with combustion gases. The gases are moving at a certain rate. You achieve got thermal transfer. If the firing rate is dropped the gases speed up and you get less thermal transfer.
This is why there are different size boilers and firing rates. The larger the firing rate the larger the boiler. If down firing was a good thing why not make 2 or 3 different size boilers and just keep dropping the firing rate? The last thing to be concerned about is flue gas condensation. Too little a flame for amount of surface area is wet metal. This causes rust a the products of combustion (acids) will eat the boiler up.
Should have asked this question before spending the money on the boiler. Money would have been better spent on a proper sized boiler. Bigger is not better!
 
 

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