A question about house radiators in U.S.A.
 

First of all, I wish you all a Happy New Year, trought all that we've past for some time January 1st.
Well, I've seen that house raidators - like the old cast iron ones in U.S.A. have the faucets (taps) dowm, unlike Europe, where at least for the hot water ones, the main tap is on the upper side. Do radiators from U.S.A. are generally use steam in stad of hot water, so this is why they have thins configuration?

Some do, some don’t. Older systems were steam, newer ones are hot water. Steam (really water vapor - it’s not at high enough pressure to be real steam) systems have one pipe, hot water have two pipes. Hot water also has a circulator pump, almost always the old rumbling B&G 100. They made that pump for ages, then the wet rotor can pumps became popular. Maybe they still make the 100. What a maintenance joy they were…

So something like this would be vaporized water: https://www.castinstyle.co.uk/produc...-iron-radiator
And this a water one? https://www.castinstyle.co.uk/produc...-iron-radiator
I don't know how good you can see it here, but on continental Europe, one of the pipes is up, the other is on the base: https://www.regatta.ro/images/w750/m...gt39862-4.jpeg
Those those pumps where good or bad wehn it camed to mantinance?
In Romania there was in use also the thermosyphon principle, so water would go up when got heated, and then camed down by gravitiy to feed the radiators.

What a coincidence, just yesterday my wife and I are watching "The Bone Collector" picture, and one of it's murderer crimes involved water steam, and my wife asked me about this structures, and if another (with cold climate) countries used/uses steam in old days and nowadays... and then today, I see this thread

Steam is used on city, industrial and campus-wide central heating systems where going longer distances without pressure and temperature drops that a hot water system would have. Steam also requires on-site boiler operators who perform maintenance operations, state pressure vessel registration, etc.

Newer hot water or "hydronic" systems use a circulator pump, but some gravity hot water systems were designed for use in pre-WWII homes.

Cast iron radiators can be used with either HW or steam but with steam, a low connection is used only. Once steam condenses in a radiator, it returns to the boiler as water, again out the low connection. HW often goes in the low for inlet and high side for outlet. https://www.thisoldhouse.com/2109707...or-performance

Below, an ornate radiator in a 140-year-old residence outside in Norristown PA
Attachment 206376

I don't see the pictures...
In U.S.A., quite a lot of cities had centralized heating - probably with steam. Seen a map in an 1942-1943 Romanian magazine (where they wrongfuly sayed it's Canada).
In Romania a lot of cities had it. But not with steam. Hot water in stad. Because it can be pumped to a longer distance. Nowdays, no more the 12-14 cities still have it. In Bucharest there is a big sistem, but in the last 12 years the system was quite negelcted, so pipes broke quite often, so no heat, no hot water sometimes.

The old B&G 100s weren’t a bad pump, but you had to lubricate them every year in the fall, and the motor mounts sagged and needed replacement every few years. And sometimes (always a cold weekend), the seals would start leaking. That sucked to fix.

The can-type pump showed up in the US in the early 70s, and became popular. Much quieter, more reliable, and they don’t leak, or need maintenance.