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# another sizing question

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Member Posts: 1,613
please help me trying to size a replacement burnham boiler I have added up the edr multiplied by 240 come up with 598.579 based on this number what would be the best size of a burnham independence steam boiler

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• Member Posts: 1,787
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Are you sure????

total edr in sq ft x 240 = 598.579? or 598,579?

If the first number is correct, than your system has one itty bitty tiny radiator. That cannot be the correct number. If the second number I have guessed at is correct, that your system edr is 2494 sq ft. and in that case, even the largest Independence model would be less that half the size that you need.

Probably would be a good idea to post your EDR for us to look at.

Here is a link to the independence boiler manual. The ratings are on the last page.

http://www.usboiler.burnham.com/products/boilers/independence/assets/literature.pdf
Dave in Quad Cities, America
Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
http://grandviewdavenport.com
• Member Posts: 1,613
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another sizing question

ok let me try again have a total of 366.5 edr of radiators have have 20 ft of 1 1/4 in steel pipe baseboard for 82 sq ft of edr 366.5 +82= 488.50 x240=107,640x155(pickup factor)=16,684,200

so based on these figures what would be the best burnham independence to use if my math is off please let me know sorry about the screw up with the 1st figures
• Member Posts: 1,787
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pickup is usually 1.34

Ed,

Pickup factor is usually an extra 33-34%.  If you have unusual or uninsulated piping situation, 55% might be what you need, I have no way of knowing.

But, here are the calculations.

366.5 edr from rads + 80 EDR from baseboard = 448.50 total sq ft edr

448.5 sq ft x 240 BTU/sq ft = 107,640 Net BTU

Boiler ratings are shown in sq ft, and Net BTU.  If you look at those ratings they alreayd have the extra 34% figured in.

Model IN6 is rated for 108MBTU Net, or 108,000 BTU Net and 450 sq ft.  If you have a normal piping set up, it is a perfect match.

However, if you really need 55% pickup factor, then here is the calc.

107,640 BTU Net x 1.55 = 166,842 BTU Gross output (DOE heating capacity)

The IN7 has a DOE heating capacity or Gross Output of 173,000 BTU and that would be the closest match.

Why are you usuing 55% for the piping loss and pickup factor?
Dave in Quad Cities, America
Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
http://grandviewdavenport.com
• Member Posts: 1,787
edited June 2011
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duplicate post

Dave in Quad Cities, America
Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
http://grandviewdavenport.com
• Member Posts: 1,613
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another sizing question

the pick up factor info came from lost art of steam heat page 75 guess i shouldn't try using a calculater when tired
• Member Posts: 1,787
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Radiators Removed?

Ed,

In that section, Dan is talking about a system where some of the radiators have been removed.  What results is a system with smaller EDR, but has piping that still exists for a larger system.  Therefore, the piping and pickup factor is greater.  If that is your situation, then it is probably a good idea.

Why don't you post again and let us know if that is the case.  I am sure once you do that, that several of the pros will jump in and tell you what they would do.
Dave in Quad Cities, America
Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
http://grandviewdavenport.com
• Member Posts: 1,613
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another sizing question

Hi Dave in answer to the question all radiators are in place
This discussion has been closed.