How to read BTU rating?

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Old 07-14-14, 01:23 PM
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How to read BTU rating?

The plate on the boiler I'm looking at has 3 BTU measurements: input, output and heating capacity. Which is the one that is referred to when someone says you need X BTUs? Thanks.
 
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Old 07-14-14, 02:11 PM
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Some use IBR rating if it has that on your plate. But your better off using DOE ratings in the boiler specs from the manufacturer IMO..

Also you need to do a heat loss calc of the home. Use the slant fin calculator in the sticky at the top of this forum...

I have found if you take 40% from the boilers output it puts you close to the IBR rating...
 
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Old 07-14-14, 02:13 PM
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Hi amk and welcome to the forum.
The input should relate the the fuel burned. The output should be that number reduced by the efficiency of the unit. A 100,000 btu input to an appliance having a 90% efficiency rating would yield a 90,000 btu output. The heating capacity should be the output, but there are some variables that should be accounted for, primarily the actual efficiency, which is often lower than mfg rating, and the efficiency of the delivery system, rarely 100%.

The often referenced "high efficiency" units only reach that efficiency level after they warm up, steady state. And delivery systems for forced hot air or baseboard can vary all over the place, especially if you are attaching a new heating unit to an old delivery system.

Tell us what you are doing and some of the pros here will be glad to advise.

Bud
See, one even posted before I could hit the button, gosh I'm slow .
 

Last edited by Bud9051; 07-14-14 at 02:14 PM. Reason: addition
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Old 07-14-14, 03:35 PM
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I'm converting from oil to gas. The contractor recommended a boiler for 144,000 BTU. He brought a six-section Burnham Independence, 245,000 BTU input, 202,000 BTU DOE heating capacity, IBR steam 152,000 BTU. My concern is that the boiler is a monster compared to what I'm used to seeing in my neighborhood (16 x 40 woodframe with stucko and alum siding, no wall insulation, semi-detached, northeast climate, radiators are a mix of cast iron and recessed aluminum with fins). I started looking around online and was confused by the different BTU values on the new furnace.

I am concerned that the unit is too big, and will have problems with wasting gas, cycling on and off, etc. and it just takes up more space than I thought.

Also, what is considered a decent efficiency rating? This unit is only 83%, at the low end of the scale. (I understand that the rating is an ideal, and doesn't reflect the actual set up in the house, but still . . .)

Thanks!
 
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Old 07-14-14, 03:42 PM
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It's 2 floors plus basement (no heat there, but may want to add in the future?), replacement windows (but don't know how good)
 
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Old 07-14-14, 03:42 PM
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Moved your thread...

Read here and do a heat loss of the home with the slant fin calc...

We can guide you... Don't buy nothing until you get your facts straight,,,


http://www.doityourself.com/forum/bo...lculators.html
 
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Old 07-14-14, 03:47 PM
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The contractor recommended a boiler for 144,000 BTU. He brought a six-section Burnham Independence, 245,000 BTU input, 202,000 BTU DOE heating capacity, IBR steam 152,000 BTU.

OMG... Get rid of that guy asap... How big is your home????

A 202 k boiler is good for an 8000 sq ft home... ( Your kidding right?)

Is your home 8000 sq ft??? ( It could be...)
 
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Old 07-14-14, 03:49 PM
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Thanks, I will sit with the calculators tonight.

Is the efficiency rating important for a steam boiler?
 
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Old 07-14-14, 03:51 PM
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Do you heat loss and post back that # you get...

Tell us the sq ft of the home...

Tell us how many zones you have...

Measure all the cast iron rads. ( Baseboard or rads? Tell us the ft or how many sections)

Tell us the length of elements on the copper baseboard totals..

We can start there. Give us as much info as you can and we can help you..
 
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Old 07-14-14, 03:53 PM
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Is the efficiency rating important for a steam boiler?
You dont have steam... Its irrellevent... Steam boilers get sized to the amount of radiators.
 
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Old 07-14-14, 04:00 PM
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2 floors, 600 square feet each floor, plus another 600 in the basement (no radiators).

So when I use the calculator and it gives me a BTU recommendation, I am then looking for the DOE heating capacity rating and ignore the other ones?
 
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Old 07-14-14, 04:06 PM
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1200 sq ft home you will be looking at a 30k btu boiler. Yes DOE...

If you want to heat the basement possibly a 45k btu boiler...

Do the calc and let us know what you get...

Also cast iron baseboard correct? probably copper and the second floor? Two zones?
 
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Old 07-14-14, 04:10 PM
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Take a pic of your baseboard please and post... Tell us how many ft please
 
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Old 07-14-14, 05:30 PM
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Lawrosa,

I just got home. The slant fin app is pretty detailed. I started entering in the information for the first room, but now it ask for temperature inside and outside. The a/c's were running, so should I wait and do this when the inside temperature isn't affected by the a/c?

Whole house is one zone. Two cast iron radiators, each 6 sections and about 3 feet tall. Two tiny cast iron radiators, each 1 & 1/2 feet tall and 4 inches deep, 4 sections. 1 recessed baseboard (material unknown) 4 feet long. 1 recessed baseboard 2 & 1/2 feet long (material unknown). Nothing in the basement except the steam pipe in the grated soffit.

Also, you said that I don't have steam, but I'm pretty sure that I do have steam?

Thanks for your help!
 
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Old 07-14-14, 06:08 PM
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I started entering in the information for the first room, but now it ask for temperature inside and outside. The a/c's were runnng, so should I wait and do this when the inside temperature isn't affected by the a/c?
There is a major misunderstanding here. The slant/fin program is for calculating heat loss in the winter, heating season. Nothing to do with summer inside and outside temps, with A/C running.
 
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Old 07-14-14, 06:38 PM
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I started entering in the information for the first room, but now it ask for temperature inside and outside. The a/c's were running, so should I wait and do this when the inside temperature isn't affected by the a/c?
LOL.. No you enter your average inside and outside temps... Usually 70 f for the inside and for your location 10F for outside...

Some are paronoid and enter 0f for outside and 72 f for inside, but that will net you a bigger boiler...


Oh wait... Never mind if you are steam... Possibly I misread


Is this what you have recessed?



http://www.heatinghelp.com/images/po...e_DSC_0962.JPG
 
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Old 07-14-14, 06:42 PM
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Please take a pic of the boiler and or rads...

Also what is the data on the plate that shows sq ft steam?
 
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Old 07-15-14, 06:21 AM
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Two each of these
 
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Old 07-15-14, 06:28 AM
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And 2 more like this little one
 
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Old 07-15-14, 06:39 AM
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Yes, that's steam all right...

Steam is sized differently than hot water. The 'installed radiation' has everything to do with boiler sizing, and the actual heat loss of the home has nothing to do with... sorta...

The radiators should have been sized to the heat loss, and then the boiler sized to the radiators.

If a steam boiler is made too large or too small for the radiation, there will be problems. It's imperative that it be sized properly.

Is the installer you've chose a STEAM GUY ? Steam boiler absolutely MUST be installed 'by the book'. There is a certain set of rules that MUST be followed when doing the near boiler piping.
Your installer must know WHAT he is doing, and WHY he is doing it. A general 'hack plumber' can NOT do a 'proper' install of a steam boiler without special training and knowledge.

If I hadda guess, I'm going to say that boiler is way oversized for the rads you've got installed.
 
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Old 07-15-14, 08:36 AM
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That boiler is steam 633 sq ft. But it does not look like you have that in radiation.

Please tell us the mesurements of all radiators in the home and how many sections.

A pic of each too..

If thats all you have from your pics below, two small, one large and two recessed, then I would think that current boiler is huge!!!!..


You can do this yourself, and I am curious to what you have,,,

Read here..

Sizing a Steam Boiler
 
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Old 07-15-14, 10:20 AM
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Doing it quickly I get about 112 sqft, though I'm not sure if I have tubular or columns?

I know that at one point there were 2 more radiators in the house that were removed before my time.
 
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Old 07-15-14, 10:47 AM
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Well thats not a lot of sq ft. Does the home heat well?

FYI the smallest steam boiler in slant fin is 81k btu doe or 254 sq ft.. GXHA 100..

http://www.slantfin.com/images/stori...laxy_gg_10.pdf

Oh but wait!! Looks like burnham is right up your alley.. Independence IN3 DOE 51K or 158 sq ft steam..

https://file.ac/etji_kkpBKc/independ...data-sheet.pdf


About 2K for the boiler.. Should not be more then 3k to install. Should be 5K or less IMO..

IN3S-EI-EZ-NG - Burnham IN3S-EI-EZ-NG - IN3, 38,000 BTU Output Independence Steam Boiler w/ EZ-Connect Package, Electronic Ignition (Nat Gas)

But get your sq ft right...
 
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Old 07-15-14, 11:07 AM
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I'm going to double check my numbers more carefully. I have the column, not tube, in the pics, right?

2nd floor heats well. 1st floor does not, with 600 sqft, with one cast iron and one recessed baseboard. At one time there were 2 more radiators on the 1st floor, but long since removed.

How do I accommodate for the possibility that in the future I may add in a radiator on the first floor and/or in the basement?

Does the energy star efficiency rating matter?
 
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