Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Please help calculate my EDR

Here are the measurements of my main, branch main and radiators, on my one-pipe steam system. I cannot see manufacturer name on the radiators so all I have are the measurements.

4 radiators @ 27 inches wide x 22 high, 16 sections 4 tube.
1 @ 18 inches wide x 35 high by 8 deep 8 sections 2 tube.
1@ 18 wide x 20 high x 9 deep 8 sections
1@ 24 inches wide x 25 high by 4 deep 14 sections 4 tube
1 @ 16 wide x 25 high x 9 deep 10 sections 4 tube
1 @ 32 wide by 24 high x 4 deep 18 sections 4 tube
1 @ 23 wide by 24 high x 4 deep 14 sections 4 tube
1@ 6 wide x 19 high x five deep 4 sections
1 @ 36 wide x 20 high x 8 deep 15 sections 5 tube
1 @ 21 wide x 23 high x 5 deep 9 sections 3 tube
2 @ 34 wide x 20 high x 8 deep 12 sections 5 tube

Main measures 2.38 diameter for each of the two pipes off boiler and join to create the main itself. The main measures 2.38 diameter.
Main measures 65 feet from furnace to end of main where branch riser taps off to go into crawl space to feed radiators above crawl space. Branch main diameter is 1.9 inches.
Main then continues for 27 feet from where branch riser taps off to end where it becomes a return.
Branch measures 60 feet from beginning of branch until it drops to a return.
Both the main and the branch drop down a couple feet of vertical pipe before they go below normal operating water line, and then the wet return travels a few feet off the floor with a nice slope until it drops to the Hartford loop back at the boiler.

First part main 65 feet @ 2.38 inches diameter plus 60 feet branch diameter 1.9 inches = 125 feet total main/branch pipe.
27 feet of remainder of main after the branch leaves, measures 2.38 inches diameter.

I have three Big Mouths on the 125 feet that consists of main plus branch, where the branch drops to return.
I have one Big Mouth and one Gorton #1 on the 27 feet of main that goes from where the branch departs to where the main drops to its return.

I feel pretty good about my venting. Steam hits the vents at both pipes pretty quickly. Pressure rises to about 1.5 psi most heating cycles, measured with a new 0 to 3 psi gauge. No short cycling. I have replaced many radiator vents already with Maid-O-Mist 5l vents, most with the smaller to mid-size orifices. I will take care of balancing radiators after I install several new clevis pipe hangers to get rid of a sag in the branch that causes some water hammer that happens about the time that steam hits the branch vent. I imagine that after I fix that sag and cure the pooled water and water hammer that my operating pressure will be lower. We will see. I have just a pressuretrol and not a vaporstat. Pigtail cleaned. Pressuretrol set to 0.5 and 1 and seems to operate well. Water nice and clean. I must also drain the wet return and use a fitting I bought to thread a garden hose into a fitting so I can slowly run water through the wet return. Unfortunately I do not have shut off valves at the wet return and Hartford loop to prevent the return cleaning from possibly backing dirty return water up into the boiler.