Help - Need BTUH cap

BHVACR

Any of you guys ever run into these old units. I am getting ready to retrofit the boiler system in an apt complex that has these in, I can't find any BTUH cap data on them. Any chance anyone here would have that info? They look very similar to the Burham DUO RAD

STEAM DOCTOR

Do a heat loss calculation

winnie

Looks like they are nominally 10K BTU rated, but the info is from an ad that doesn't provide temperature deltas, flow rates, etc.

https://www.usmodernist.org/AB/AB-1955-07.pdf page 136

Given that the label you show say that PEBCO is a division of Burnham, and that the unit looks very very similar to the Burnham B50 units (from Lancaster, PA even) shown in https://heatinghelp.com/assets/documents/Burnham-America.pdf on page 89, I would bet a couple of beers that they are the same.