Help with EDR of this radiator

Precaud

When I did my "EDR audit" a couple years ago, I forgot to include this ceiling-mounted one near the basement entrance, because I have it shut off. I don't see an equivalent to it in any of the radiator docs I've found from HH searches.

It's 22" H x 42" W, 18 tubes, and 1 section (thick).

Any ideas?

Steamhead

7 square feet per section, and 3 sections, total 21 square feet.

Precaud

Thank you!

mattmia2

It is a pretty standard wall hung commercial radiator. Lots of gyms and pools and auditoria and theaters had the walls liked with them in the early to mid 20th century.

Precaud

That's interesting context.

Adding this one brings the total EDR of all of the installed radiators to 428.

I have been assuming that my boiler was oversized, but that may not have been the case. Revisiting my system's basic specs:

The 525 is 126,000 / 240. Is that the figure to use? If so, it is definitely oversized. Going by the "Installed Radiation" spec, it is actually undersized... or would be, IF all of the radiators were being used. And neither include a derating for altitude (7,000 ft).

Subtracting the 143 sq ft of radiators that are turned off leaves 285 active. Now it does look a little oversized. But with altitude derating (how much?), it would be closer, no?

mattmia2

the installed radiation has a pickup factor subtracted although the 30% used now doesn't seem to account for that number. the 525 seems to be the actualk output, maybe the 342 is 30% pickup factor and also some losses through the jacket and such. in a typical system if you are under the 525 -10% or so you should be fine so it is probably good to about 450-475 ft^2 or radiation. if it is 2 pipe the boiler can easily be undersized a bit.

Precaud

The 342 would be a 35% pickup factor.

I just read that derating for 7,000 ft is 20%, so 525 x .8 = 420 . Which is very close to the original 428 this system had when installed. So it appears the original installer knew the math and sized it accordingly.