You've just proved me right, Dimmie. It is you who doesn't understand
the English language, Dimbulb. "Hydronic" modifies "boiler".
"Boiler" is one word. That which heats water for space heating
purposes is called a "boiler". That which heats air, for the same
purpose, is called a "furnace". Now, go back to thinking up *new*
ways of being wrong. This one is old.
Interestingly, in English English, a furnace would usually be something
that is used to heat material to a very high temperature - eg to melt
metals. The word wouldn't be used for something that merely heated air
to a few tens of degrees above ambient.
Conversely, the Oxford English Dictionary defines a boiler as, "A
fuel-burning apparatus for heating water, especially a device providing
a domestic hot-water supply or serving a central heating system".
If the "boiler" is electrically powered, but doing the same job of
heating water by a few tens of degrees - it would be called an immersion
or hot water tank - and not a boiler.
I can't comment on the meaning of the words in American English. But
there are, of course, many words that differ in meaning between America
People walk on the pavement in the UK. They wear trousers over their
pants. Teachers hand over a rubber to their students to use to correct
their mistakes and not to prevent them..
This diagram shows a very typical central heating system in the UK:
"Boilers" -in the sense of a device for deliberately producing boiling
water - is a term mostly confined to marine engineers.. in the UK.
There was actually a very serious accident in the UK recently, when a
fauly central heating boiler did indeed produce boiling water. The
diagram shows that a tank in the loft is used to hold feed water for the
heating system. It also takes the excess as water in the system expands
as it is heated. In this accident, the boiling water led to a lot of
expansion and a lot of very hot water going up into the tank. The tank
was made of plastic (again very typical) and softened - allowing its
contents of several tens of gallons of water to pour out into the loft,
through the ceiling and onto the bed of a child sleeping in the room
below. Very, very sad.
...and get "knocked up" by the hotel staff in the morning.
This is quite similar to one of the heating plants commonly used in
the US, except we don't normally have the "feed tanks", and never in
the attic (if that's what the schematic is showing). Instead of the
feed tanks the boiler and domestic water are fed from the city water
or well (with perhaps a small storage/pressure tank). The boiler has
a pressure reducer off the main water supply and usually an expansion
tank to take up the slack.
Your diagram shows the option with the heat exchanger and storage
tank for domestic water. That's fairly common, but more common is a
separate heating coil in the boiler. Separate water heaters are also
common, particularly if gas is available. I had the domestic coil
because the boiler was converted from oil to natural gas and never
got around to changing the hot water supply.
Steam boilers are also used in large commercial/industrial
applications and some older homes. They're no longer used much for
Ouch! There was a steam accident recently in NYC where an
underground steam main blew, killing a woman on the street above.
High pressure steam can be nasty.
That qualifies also as a furnace here in the USA. What would a domestic
force air furnace be called in the UK?
That was not from the steam, but a hart attack. The injuries to the other
victims are quite serious. I think one is still in the hospital. Thought the
Tow truck driver and passenger (the tow truck ended at the bottom of the
hole) both have been released for a while now.
What would you call something that heats air to heat a building?
Tell that to Dimbulb.
The boilers I've had heat both domestic and heating water. They've
had a separate coil in the boiler for the domestic water, making the
boiler more or less a tankless heater. Some use an external storage
tank with a heat exchanger and a zone off the heating water to heat
If it's used to heat domestic water it's called a "water heater".
I've never heard of electricity used in a hydronic heating unit.
Perhaps they're not used because the water has to be heated to at
least 180F to get any efficiency out of the baseboard radiators.
Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here.
All logos and trade names are the property of their respective owners.