Steam Main Insulation Question

markmarlatt

Do I need to insulate the steam mains after the last radiator branch on the leg? Right now both steam main/legs are insulated from start to end. I’m should I leave it that way? Do the legs need insulation after the last radiator supply leg? I have one leg that has 30 feet after last radiator branch to above the boiler.

Wondering if I should remove insulation after the last radiator to enable the steam to quicker return to liquid. Thoughts?

Captain Who

Sounds like you are talking about a dry return. Mine are insulated. In turning to a liquid quicker it gives up it's latent heat to the pipe and to the basement quicker. If that's what you want, then leave it uninsulated, but you will lose efficiency and have to burn a bit more fuel to satisfy your thermostat in your living space. It's like having another radiator in your basement.

Jamie Hall

You are talking about a steam main extension — which some referr to as a "dry return", which it isn't and which is a very different beast.

Having said that, a steam main extension is carrying steam — and anything that carries steam should be insulated if possible.

And the LAST thing you want to do is to be condensing steam (which is heat — and money!) somewhere where it isn't going to heat your structure.

ethicalpaul

Depends where the main vent is. Steam won’t really go past the main vent if it’s after the last radiator.

Some people insulate everything then find their floors are too cold. Do what makes you comfortable, the system won’t mind.

4GenPlumber

If you are looking for that pipe to add radiation to your basement then yes. Thats the only reason to remove insulation, if you are using that energy to make your home more comfortable.

markmarlatt

Thank your for the feedback. I have a two pipe system, the main is insulated from boiler to boiler all around the basement. I was mainly curious if it made sense to have the main insulated near the end of its run back at the boiler:

I bought the house ten years ago with this setup and will be having a second round of near boiler piping done in next two weeks to correct return piping and to establish a Hartford loop that has never existed.

When I had all traps and valves at the radiators replaced as well as adding three Gorton #2 vents to the ends of the steam legs and the wet return, the system heats muck quicker but the flaw in the incorrect return piping and lack of Hartford loop has resulted in frequent hammering as one of the legs is connected to the wet return above the water line and so it’s possible for steam to get into the wet return. Again this will be addressed at next visit from of the tech.

The insulation question is a curiosity I had as to whether there was any benefit to insulating a main/leg after the last radiator branch. I will leave or retain all insulation I wager.

mattmia2

if it is 2 pipe the mains should all be insulated. the returns do not need to be insulated although if they already are it will make the system slightly more efficient but probably not enough so to pay for the insulation.

markmarlatt

https://forum.heatinghelp.com/discussion/comment/1888646#Comment_1888646

Here is video tour of my steam pipes;

https://youtu.be/9OSzL_NkKN0?si=PErjE8Z6UMjl4SA8