Counterflow + dry return = trouble?

NormanR

I'm a homeowner with a noisy, uneven, spitting, one-pipe steam system. I intend to have it redone but I need help with a question about returns. Background first.



Everyone agrees that the near-boiler piping is a disaster (Burnham IN6 with a 90-degree elbow 1 inch above the top of the boiler; other madness). It will be replaced. But I can't get a consensus on what to do with the mains.



The system is a counterflow system with two mains. The rear main runs straight for 20 feet. The front main runs 9 feet, makes a 90-degree turn, then runs another 18 feet. I found it a bit hard to measure the pitch as both mains are covered with hard clamshell fiberglass insulation, and my longest level is only 2 feet. But as near as I can tell, pitch varies from about 1 inch in 5 feet at its steepest to about 1 inch in 8 feet at its most shallow, which seems like it should be plenty. I'm not competent to evaluate sizing as I don't know how to look at the outside of a pipe and tell its nominal diameter.



One of the mains has had a dry return added. Both of the plumbers who have been to the house agree that this dry return is not original and that it is too small. (Pictures below.) But they propose completely different solutions:



<ol><li>Plumber No. 1 wants to replace the dry return with a new one that has a larger diameter. An probably also install a return on the rear main. Or else leave this part of the system alone; he says it's my decision.

</li><li>Plumber No. 2 suggests closing off the dry return entirely, or maybe not---he wasn't very sure of himself.</li></ol>

I myself am a little skeptical of the value of a return in a counterflow system. Maybe it helps the radiator at the very end of the line somehow? But I'm having trouble figuring out how the condensate flows uphill, especially from the other three radiators. Maybe when the steam is flowing it's supposed to push the condensate uphill?



I have no way of knowing whether the dry return that is installed now was put there for a good reason by some Dead Men, or if it was put in by the same species of knucklehead that did the near-boiler piping.



My question for the forum: is there any reason to have a dry return on a counterflow system? Or should this return simply be retired and sold for scrap?





Norman



P.S. I am aware of the possibility of installing a drip line in each main near the boiler and running them into a wet return. But that would be a completely different animal.



PPS: Four photos attached:



1. View of front main looking toward front of house. One radiator is fed going away from the camera. You can see the vent and the bend into the dry return. I believe the vent is not functioning.



2. Side view of same area, looking down the main and return back toward the boiler. Radiator feed is to the left.



3. View of main and return, showing pitch as best I can



4. Near-boiler piping, in case anybody wants a good laugh (or a good cry).

JStar

Steam

The return looks close to original. The size is based on the attached load from the main. No guessing allowed!



If it's a true counter-flow, the extra return won't matter. It does need a proper drip return near the boiler, though.

NormanR

counterflow: true or false?

Joe,



How would I tell a "true counterflow" from something else?



As for load, I can use Dan's charts to estimate the EDR load on this main. That would then give me the correct size of the dry return? What function does the dry return perform in this system?

JStar

Counter-flow

There would be certain piping techniques used for a counter-flow system. They are easier to identify in person. I would just assume that this is not a counter-flow system.



Your biggest, and maybe only, issue is the boiler piping.