Oversized - can you check my math

Si_zim

I have a ThermoFlo GSA-150 - which has 125k net BTUh capacity apparently.

I attach a file with radiator CF/BTU workings. Pipes are pretty well insulated so I think the default pickup will be fine. Seems to total 242sq ft and 58k BTU.



There is also a zone of hot water baseboard 29ft long for roughly 15k BTU.

So my estimate is that I have about 73k BTU of radiation... boiler is way oversized.



The addition with the baseboard got chilly during the recent cold spell so I think they did not spec it right for the windows, cathedral ceiling etc. So I would like to swap out the basic slant fin for the Multi/Pak jumbo fins for about 800BTU/lineal ft (total of 24900) and move some of the old slant fin down to the basement for another 9k BTUs there.

This comes to a total of 92k BTU - which should still be safely under the boiler's net capacity... hopefully warmer all round and less cycling on the steam side.

If anyone could review in case I missed something - would appreciate it

Si_zim

tried to upload

Well I tried to upload as XLSX and RTF files with no luck... will try to post the table somehow

Si_zim

Hope this works

RADIATOR      Height in Style no width  section  sqf/sec  rad sqf EDR  RAD CF    BTUh

Grnd floor bath     19      tube   4    4.5     14         1.7            23.8                0.3094  5712

Sitting rm left        22      col    3     9     14            3                42                      1.05 10080

Sitting rm right      22      col    3     9     14           3                42                      1.05 10080

1st floor bath        25.5   tube   5    8      6           2.7             16.2                 0.2106  3888

Front bed              19      tube   4   4.5     20       1.7              34                    0.442   8160

Master bed           21      tube   4   4.5     22       1.7             37.4                  0.4862  8976

Back bed              25.5   tube   5     8      8          2.7             21.6                 0.2808  5184

Attic                      37      col     3     9      5           5                 25                    0.625  6000

                                          Total Sq f       242                   Total BTUh 58080

Jamie Hall

It's so much simpler

to work with EDR, which boilers are rated in, rather go through the headache of adding a pickup factor (or maybe not... or maybe a bigger one... or...)



What is the EDR rating of that boiler?  Compare that with the EDR for your radiation, and there you are.  If the boiler is over, then you can go and convert the excess EDR to BTU and use that number to see what you can do with the addition...

EBEBRATT-Ed

boiler capacity

You can safely add that baseboard.

Si_zim

Boiler manual says 394ft EDR

Not sure what normal slant fin baseboard EDR is but seems like I do have more than enough capacity.

Wonder why they had such a beast installed

Si_zim

Down fire?

Even with my plan to increase baseboard it seems the boiler may still be a bit oversized. I guess over time efficiency may drop and it is good to have a safety margin - but wondering if it would be more efficient to down fire it a bit also?

Does anyone have experience with Thermoflo (standing pilot) or is an agent for them - so I can find out if that is a possibility?



Thanks again