Home Addition/existing steam(mk)

Mike Kraft_2

steam job I'm looking @.The convectors in the home are actually WM/Raydiant Concealed Radiators.Page 171 in EDR.There are also 3 tube type rads on the second floor.Converting the two floors to EDR I come up with a grand total of 203 sq'.Using a multiplier of 1.33 for the pick up factor I add an additional 270sq'.But if I go to LAOSH page 75(new book) Dan has a 1.5 multiplier that you than multiply the answer x 240 to convert to MBH.He then tells us to use this answer to take to the manufacturers boiler charts and pick from the DOE column.


My pickle :)...................203x1.33=270+203= 473sq'(old way)


203 x 1.5=304.5 x 240 =74K


The existing boiler rating is - IBR net 88K(water)


Steam sq'-317




Steam MBH-76K


Seems the #'s conflict a bit .The boiler MBH works but the pick up multiplier 1.33 shoots you over the Man's rating of 317sq'.Ths job has additions to the home.More heat and the boiler is maxed now as I see it.Looking for opinions.

Thnks,

cheese

Boilerpro_3

Got you totals crossed up

The pickup ffactor is 33% or .33 not 133% or 1.33.
So you've got 203EDR
Pick up Factor 202 X 33% (.33) =

Boilerpro_3

Got your totals crossed up

The pickup factor is 33% or .33 not 133% or 1.33.
So you've got 203EDR
Pick up Factor 202 X 33% (.33) = 67 EDR
Total load = 270 EDR

270EDR x 240 = 64,800 gross boiler output

The .5 pick up factor is to help account for oversized piping when some radiators have been removed, as is the case for most old steam systems. It sounds like you may have some added on your system, so 33% is probably OK.

Boilerpro