[jadams5]

I live in a 90 year old house that still uses the original steam heated radiators. It's actually been a lot of fun learning about the old technology with its pros and cons.

As an example, I always assumed that the radiators were always just full of steam while running, but the systems actually work by cycling between steam production and condensation phases. There's an alcohol filled bladder at the base of every radiator that boils and expands when the steam fills the radiator, sealing off the flow at that point, forcing the steam to route around to the next radiator. Once all the radiators seal off the pressure in the system rises, triggering the boiler to shut down. The water condenses inside the radiators as they emit their heat and cool, the bladders open, the water drains back down to the boiler, and if the home temp is still low the cycle starts again. Who knew?

For now we're actually planning on keeping it around while it's all in good working order.

[nkurz]

Interesting. I think the system you are describing is a variation of a "two pipe steam" system that is not very common these days. More common systems have have an air vent, and do run on a continuous cycle.

Holohan describes the differences here: https://heatinghelp.com/systems-help-center/a-steam-heating-...

He also points out that the failure point of the system you have is that the "steam traps" tend to fail frequently and silently. The system still heats, but runs less efficiently. He says the traps typically have only a 3 year lifespan.

[jadams5]

Yep, it's a two pipe system. One of the first things I did was verify that the traps were all functioning. Amazingly enough, they were!

The house was built in the 20's by a commercial plumber who put in some more commercial-style amenities including some state of the art for the era tankless flush-valve toilets. I love them, wife hates them.

[soperj]

>tankless flush-valve toilets

Quickly tried to find a picture of this, but don't know what exactly i'm looking for. Can you post a link?

[jadams5]

https://en.wikipedia.org/wiki/Flushometer

edit: It's just like what you'd find in any modern commercial building in the US, just with a much older form factor of toilet. When we moved in I got curious why most new homes don't have them. Found out that they don't use any more water than a normal toilet, but they do require a higher water flow rate. The high flow rate requires at least a 2" water main into the house (which we have), while most modern residential construction uses a 1" or less.