Mystery Elbows

a3inverter

All,



Still getting to know the steam heat in my new (to me) old house.



Several of the radiators appear to at one point had 2 pipes going to them (there are telltale holes in the floor that were plugged/filled at one point)...and some still do.



None of them have valves on them, but they all have air vents.



I am wondering if what appear to be just 90 degree elbows are actually steam traps.



In the attached pictures, the first 3 are of a radiator with a capped return.  The last 2 are of a radiator with the return still plumbed.



I keep finding crazy hacks on these...like the radiator in the kitchen that had a hot water bleeder valve installed...with a hole drilled in the side of it to make a really big "vent".



Any thoughts?



Thanks!

Dave in QCA

More pictures

Do your radiators have any kind of venting device?  We need more pictures of the parts of the radiator that we cannot see.  Perhaps a picture of your boiler too. 

This is looking like a hot water system.

a3inverter

Definitely Steam

It's a steam system.  All the radiators have Vent Rite #1's.



I've attached some pictures of the radiator vent, the boiler, the near boiler piping, the returns (are these drip returns?) and the antler I installed a week ago.

Dave in QCA

I was wrong and that hunch!

You are correct, definitely steam!



Looking at the pictures in the basement, I am guessing that the black iron pipe that runs horizontal about 2 feet above the floor is the return line for the system.  At this location, it is below the water line and not capable of providing any venting or passage of steam.  That would make your system a 2-pipe vented system.

In this type of system, all venting is at the radiators.  Condensate travels by gravity out of the return connection and back to the boiler.  Since that line is below the water line, air and steam cannot travel out of the radiator at this connection, so no traps are needed. 



I am surprised to see this setup in a system that appears to be from the 1930s.  I thought the 2-pipe vented systems were installed early, usually before 1900.



As for your elbows, my guess is that they are simply union els, the same type as installed on a hot water system.

a3inverter

Good Guess on the Age

You are right on there...house was built in 1930.



Thanks for the detailed explanation...I don't know why some of the radiators were converted to 1 pipe, but it is what it is.

Dave in QCA

guessing

I am guessing that your smaller radiators are 1-pipe.  Maybe all of the first floor radiators are one pipe?

The advantage of this type of 2-pipe system is that the supply connections to the radiator, as well as the supply risers and runnout could be smaller pipe sizes since they do not have to handle both steam on condensate.

a3inverter

Yes

...all my first floor radiators are presently 1 pipe...however most of them show evidence of having 2 pipes attached. 



Why did you guess this?  Is this good or bad?

Dave in QCA

Neither good nor bad

I have seen a system done this way.  The reasons for it are that running full size pipe for 1-pipe rads is easier to do on the first floor.  Running smaller pipes to second floor rads simplifies the installation, even though it requires a second pipe.  The small pipes are easier to hide inside the wall cavities, and generally easier to install all the way around.



The system that I am familiar with, the vents for the second and third floor radiators, instead of being on the radiator, are actually on the return pipe, just below the basement ceiling, yet well above the water line in the wet returns.  It works great and I have never seen another system like it.  Like yours, the first floor rads are all one-pipe.

a3inverter

Makes Sense

I understand...thanks again for the explanation.

Steamhead

Do the return lines from these radiators

run to a dry return (above the waterline) or the wet return in the picture?



Is it possible that the original boiler was down in a pit that has been filled in, and what is now a wet return was once a dry return?



This setup sure looks like Orifice Vapor to me, knuckleheaded by adding radiator vents.

a3inverter

Returns

The returns from these radiators run into the Wet return.



I don't see any evidence of a pit being filled in...I only see the shadow of a circular outline (with a chord facing forward) that might indicate where the original "snowman" (assuming here) sat.

Dave in QCA

I thought so too

Steamhead, I thought this was strange too!  I've never seen a 2-pipe vented system with elbows on the outlet, usually valves.

a3inverter

Orifice Vapor

My perception, based on reading posts to this forum over the last few months, is that orifice vapor is a very good system to have.



If that's correct, what are the advantages over what I have today and what might it take to go back to it?