Using GPT to calculate EDR, BTU, etc. Is this on the right path?

CoachBoilermaker

Using GPT for hypothetical replacement boiler sizing.

If my calc lands on 58,000BTU, what rated boiler would I replace it with?

BR #1 (8 sections, 19" W x 22" H):

• 8 sections x 3.0 EDR/section = 24.0 sq. ft.

BR #2 (7 sections, 17" W x 38" H):

• 7 sections x 4.0 EDR/section = 28.0 sq. ft.

BR #3 / Primary BR (17 sections, 45" W x 25" H):

• 17 sections x 4.0 EDR/section = 68.0 sq. ft.

LR (20 sections, 50" W x 21" H):

• 20 sections x 3.0 EDR/section = 60.0 sq. ft.

DR (16 sections, 40" W x 26" H):

• 16 sections x 4.0 EDR/section = 64.0 sq. ft.

Summary of EDR:

• BR #1: 24.0 sq. ft.
• BR #2: 28.0 sq. ft.
• BR #3 / Primary BR: 68.0 sq. ft.
• LR: 60.0 sq. ft.
• DR: 64.0 sq. ft.

Total EDR for all your radiators:
24.0 + 28.0 + 68.0 + 60.0 + 64.0 = 244.0 sq. ft.

This total EDR is the equivalent heating surface required to effectively heat your home using steam. If you need further details or adjustments, let me know.

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With a total of 244.0 sq. ft. of EDR and a house size of 1600 sq. ft., the radiator system seems well-suited for heating your home, especially if it is primarily heated by steam radiators. Typically, each square foot of EDR emits about 240 BTU/hr.

Given the 244 sq. ft. EDR:

Total BTU/hr=244×240=58,560 BTU/hr

This is the total output from your radiators, which should be adequate for heating your 1600 sq. ft. house, assuming normal insulation and climate. Steam systems usually heat spaces efficiently, especially in colder weather.

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The General Motors Delco DB-4S oil boiler is a relatively older model, and detailed specifications might vary depending on its exact year and configuration. However, for a typical Delco DB series oil boiler, the BTU rating is usually in the range of 100,000 to 150,000 BTU/hr, depending on the specific unit and its setup.

ethicalpaul

you ignore BTU because the manufacturers already give you a number that compares directly to EDR which is "Net Sq Ft of Steam"

The Peerless 63-03L is a good match for your EDR at 233 Net Sq Ft of Steam

EdTheHeaterMan

@CoachBoilermaker said: BR #1 (8 sections, 19" W x 22" H):

8 sections x 3.0 EDR/section = 24.0 sq. ft.

I can't help but wonder what radiator chart has 18" wide radiator sections.

@CoachBoilermaker also said: LR (20 sections, 50" W x 21" H):

20 sections x 3.0 EDR/section = 60.0 sq. ft.

I can guarantee you that no one ever made a 50" wide radiator section.

So I am wondering if @CoachBoilermaker selected the correct section EDR for his calculations. This chart along with three pictures of actual radiators,

is an approximation of what different radiators might look like when comparing them to that chart. If you don't get the actual measurements that are close to the chart, then you need to find the old manufacturer's specifications. A lot of them are found in this book

https://www.heatinghelp.com/store/detail/e-d-r-ratings-for-every-darn-radiator-and-convector-youll-probably-ever-see/

So double check your EDR calculations. The width of the radiator is not on the chart. the width of the section is on the chart. You might call that the Depth of the radiator

CoachBoilermaker

LOL. Good catch. I measured the length of entire radiator and height.

I updated my measurements but GPT only estimates EDR by height, so it calculated the same BTU total.

BR #1
8 sections
9" (W) x 20" (H)

BR #2
7 sections
9" (W) x 35" (H)

BR #3 / Primary BR
17 sections
6" (W) x 23" (H)

LR
20 sections
9" (W) x 19" (H)

DR
16 sections
9" (W) x 24" (H)

EdTheHeaterMan

The chart I gave you above, will tell you the number of tubes or columns associates with a particular width. If GPT does not offer you that information to double check your EDR with the actual measurements, then you may be off by a lot. If your 9" wide 20" tall radiator has 3 columns then your EDR per section should be 2.75. If your 9" wide 20" tall radiator has 6 tubes then your EDR per section should be closer to 3. If it has only 5 tubes the the EDR per section is 2.66. Those three different sections that are 20" tall have a significant amount of different when you total up over 60 sections.

CoachBoilermaker

@EdTheHeaterMan I recalculated using your chart

and arrived at 220 sq.ft EDR and 53k BTU

Thanks!

ethicalpaul

You are still looking at the smallest boiler by any manufacturer with 220 sq ft