Unusual 2-Pipe Steam System

New England SteamWorks

When I walked in to the house and saw all the radiators with 2 floor-level valves and a vent, I expected to find that each of the returns in the basement dripped into a wet return.

But I did not. Instead what I found is on the hastily sketched and attached diagram: Dry returns. I found standard radiator vents, no orifice plates in the valves, no traps, no main venting, and no nomenclature to provide a clue.

Another oddity that is initially confusing is that, rather than using a larger diameter pipe for the radiator supply and a smaller diameter for the radiator return, they used (identical) larger diameter pipe for the 1st floor radiators, and smaller (identical) diameter pipe for the 2nd floor radiators.

The system is not heating well. Very unbalanced and noisy. Steam is in the returns, obviously.

Was there a special type of vent to limit the steam originally? Doesn't seem likely that all the orifice plates would have been removed. I am certain there were never traps. The install seems high quality, and no sign of it having been knuckle headed.

My thought is to remove the radiator vents, add in-line traps in the basement on each return, and add main venting.

But I thought I'd run it by everyone to see what percolates.

Thanks.

EBEBRATT-Ed

Sounds like 2 pipe air vent system. Add traps or run a wet return and leave the air vents

Jamie Hall

Two pipe air vent system. There's a good writeup on the in Lost Art...

New England SteamWorks

Thank you Jamie! I found in TLAOSH.

What is interesting here is that the radiator supplies and returns are the identical size, presumably making things worse...

Ironman

Yep, 2 pipe, air vent. They can be touchy if anything's been changed.

Try throttleling the return valves a little.

Danny Scully

Hmm, that’s not typical of a 2-pipe air vent system to have same size supply/return. And very interesting how they piped the 2nd floor radiator under the first floor radiator...I’ll be pondering this tonight for you @New England SteamWorks

Steamhead

The counterflow steam mains are unusual. Maybe that was originally a gravity hot-water system and someone converted it to steam?

Danny Scully

I thought that as well @Steamhead, but you had the guts to say it I have a customer who’s house was moved. I believe the same is true of her radiators. Before the house was moved it was hot water, but once it met its final resting place it became steam I theorized this because all the air vents were in the upper plug location and all the radiators were also plugged on their return side with a regular (ugly ) plug not a radiator plug (therefore assuming not original).

Steamhead

We've seen several such conversions in Baltimore.

jumper

Steamhead said:

We've seen several such conversions in Baltimore.

Some people do not believe it is possible. I think some conversions even worked without radiator vents?

DanHolohan

Are the radiator valves original?

New England SteamWorks

The radiator valves appear to be original, yes.

DanHolohan

Love to see a tight closeup if you have one.

New England SteamWorks

I'll get one for you. It will be a bit before I get back there however.