Arco 2-pipe orfice system

Ban

While enjoying holiday breakfast I got into a conversation about my soon-to-be brother-in-law's steam system. The problem was no heat on 3 of the 10 radiators. I believe the system to be an Arco. The questions I have in particular are:



1. Does anyone have any original documentation on the Arco system?

2. What is this air eliminator device at the top?

3. Were the Arco systems meant to run on a vacuum?

4. Were the Arco systems meant to have air vents on the mains?



On this particular system, at the end of the supply steam mains their is a 1/4" hole tapped on the top of the pipe with an air vent on the loop and a plug on the other. We are having problems with the radiators on the loop with the plug. Did Arco originally intend for the steamfitters to drill and tap the main for the removal of the air or was this a retrofit? The house has at least 2 capped areas on the main and return lines where there is evidence of radiators being removed.



Thanks for all of your help in advance!

Steamhead

That's an "O-E" system, not an Arco

you can tell by the return elbows. This system is covered in chapter 15 of Dan's book "The Lost Art of Steam Heating". The radiators look like they were made by American Radiator Co, but this system they are used on is an O-E.



The air eliminator is just a main vent that could hold vacuum. You can replace it with a main vent like a Gorton #2. If the steam mains don't have vents, they should be added.



The pressure control on the boiler is the wrong type. You need a Vaporstat that can control the pressure within ounces, since that is all this system needs. The boiler itself is piped wrong- it only has one riser to the header, but the instructions call for two.



Where is this system located?

Ban

O-E system

I am in Detroit. This system is in Grosse Pointe, Michigan. I know that the near-boiler piping is not as per the manual. It is also unfortunate that the installer decided to take other short-cuts such as use cinder blocks for the pedestal. I am still confused on the idea of drilling and tapping the end mains. Do you think this was an original approach?

Steamhead

No it wasn't

someone who came later had the right idea but didn't go far enough.