Help Finding EDRs

tim51

We are in the process of sizing a boiler replacement for a 1921 school building (now a community center). Presently
has a coal fired 2 pipe steam system from around 1950. Problem is finding EDRs for convectors and fan coils. Have gone through Dan's book "Every Darn Radiator" and did not find them. We will start with the convectors. The enclosures measure 5" deep by 15" high. Inside they are made from 2" steel pipe with 4" square fins, and range from 3.5 ft double row to 27ft single row. Pictures below.

mikeg2015

Can’t find any original drawings of the building in the archive? Most schools were pretty well engineered originally. It will have a page with all of the specs of each component of the system including boilers. Boilers often originally heated DHW with shell & tube HE with some separate units for summer use.

Any make and model numbers? Might get lucky and find an old cut sheets for a similar but newer version.

Other option is to take some measurements of the pipe size, fin spacing, # of rows and some pictures and maybe see if Trane or Modine might help you out. Tell them you want to price some replacements for budgeting.

Big Ed

http://www.slantfin.com/wp-content/uploads/2015/11/Bare-Element-Submittal-Data-916.pdf

Steamhead

Beacon-Morris sells something similar. Their site seems to be having issues at the moment, but you can access the PDF showing dimensions and ratings directly here:

http://beacon-morris.com/modules/lit_lib/download.asp?litFileID=1688

tim51

Thanks to all. That was exactly what I needed. Now onto the fan coils: Coil measures 20"x20". One row deep of 1/2" copper tubes
brazed on 1" steel headers. See pics.

tim51

Having problems posting picture of label. It says Sturtevant Speed Heater size 75 style 1423046. Westinghouse, Sturtevant
Division

Steamhead

If you can't find anything specific, just use the maximum EDR the supply pipe will handle.

the_donut

Is that a dirt leg on bottom right?

tim51

That is a dirt leg and we have cleaned it out.
Picture of fan coil tag below.

mikeg2015

75 could mean 75000 btu. A modine unit heater the same size is about that capacity and model is numbered that way. However, that’s 2psi steam and 60f entering temp. For 75f air up at the ceiling and for how old and dirty the coils are and fan performance, I’d use a correction of 0.85. So EDR of 265.

Go to either ecomfort.com or go to the Modine website for the performance data of their units for correction factors.

mikeg2015

Keep in mind too that EDR ratings often assume 60f entering temp and 2psi steam. If you are different that that on any of the heat exchangers you are calculating, you can end up over sizing the boiler to the actual connected load. Pickup already is pretty generous.