what's a 1 pipe system?

[dextrous]

There's the other way of doing it, where instead of pumping the water in one direction (eg clockwise), or in alternating directions (bit like the german as described - bit like their invading a country then reversing back out a while afterwards ), you pump the water in the other direction (ie anticlockwise). That way, the colder rads are now hot

 

[holmslaw]

It's called expansion twgas

Everything expands as it gets hotter.

That is wrong.

I'm all ears

Frozen water.

Also the heating system some of the numpties are attempting to describe is called reverse return.

 

[doitall]

It's called expansion twgas

Everything expands as it gets hotter.

That is wrong.

I'm all ears

Frozen water.

Also the heating system some of the numpties are attempting to describe is called reverse return.

Frozen water expands as it gets hot

And the numpties are not attempting to describe a reverse return, and not only that a reverse return is not a heating system, but a way of piping two or more boilers to a common header.

 

[holmslaw]

It's called expansion twgas

Everything expands as it gets hotter.

That is wrong.

I'm all ears

Frozen water.

Also the heating system some of the numpties are attempting to describe is called reverse return.

Frozen water expands as it gets hot

And the numpties are not attempting to describe a reverse return, and not only that a reverse return is not a heating system, but a way of piping two or more boilers to a common header.

All you're proving is you know nothing about the physics of water and sweet f*** all about heating systems. Reverse return is a very popular method because - no point continuing way over a deaf and dumbers head.

 

[ColJack]

water expands as it freezes.. which is why frozen pipes burst..
it's due to the crystaline nature of the solid..

as the ice melts, it shrinks to it's maximum density which is at 4ºC, then it expands again....
however ice itself, once formed actually shrinks as it gets colder.. but is still less dense than water at 4ºC which is why ice floats on water..

 

[doitall]

water expands as it freezes.. which is why frozen pipes burst..
it's due to the crystaline nature of the solid..

as the ice melts, it shrinks to it's maximum density which is at 4ºC, then it expands again....
however ice itself, once formed actually shrinks as it gets colder.. but is still less dense than water at 4ºC which is why ice floats on water..

It shrinks as it gets colder, so it must expand as it gets warmer.

minus 320c would be smaller than minus 120c.

 

[dextrous]

water expands as it freezes.. which is why frozen pipes burst..
it's due to the crystaline nature of the solid..

as the ice melts, it shrinks to it's maximum density which is at 4ºC, then it expands again....
however ice itself, once formed actually shrinks as it gets colder.. but is still less dense than water at 4ºC which is why ice floats on water..

It shrinks as it gets colder, so it must expand as it gets warmer.

minus 320c would be smaller than minus 120c.

So if you could make it even colder that 0 kelvin, it would eventually become a black hole Which means that you wouldn't be able to see it since light would bend into it, and also a cubic foot of water would be very small indeed. Sorted!!!

 

[Agile]

So if you could make it even colder that 0 kelvin, it would eventually become a black hole Which means that you wouldn't be able to see it since light would bend into it, and also a cubic foot of water would be very small indeed. Sorted!!!

I am sorry to disillusion you but a "cubic foot" of water is ALWAYS a cubic foot regardless of the amount of water it contains!

Tony

 

[dextrous]

So if you could make it even colder that 0 kelvin, it would eventually become a black hole Which means that you wouldn't be able to see it since light would bend into it, and also a cubic foot of water would be very small indeed. Sorted!!!

I am sorry to disillusion you but a "cubic foot" of water is ALWAYS a cubic foot regardless of the amount of water it contains!

Tony

No, no no Tony! An American "survey" foot is 0.000002 longer than the international foot.

 

[Agile]

No, no no Tony! An American "survey" foot is 0.000002 longer than the international foot.

"""By the time the international foot was defined in 1959, there was already a huge amount of survey data which had been collected based on the former definitions, especially in the United States and in India. The small difference between survey and international feet would not be detectable on a survey of a small parcel, but becomes significant for mapping, or when a state plane coordinate system is used, because the origin of the system may be hundreds of miles from the point of interest. Hence the previous definitions continued in use for surveying in these two countries for many years, and are denoted survey feet to distinguish them from the international foot. The United Kingdom was unaffected by this problem, as the retriangulation of Great Britain (1936–62) was done in meters.

The United States survey foot is defined as exactly 1200⁄3937 meters, approximately 0.3048006 m.[3] In 1986 the National Geodetic Survey (NGS) released the North American Datum of 1983, which underlies the state plane coordinate systems and is entirely defined in meters. An NGS policy from 1991 has this to say about the units used with the new datum to define the SPCS 83:

In preparation for the adjustment of the North American Datum of 1983, 31 states enacted legislation for the State Plane Coordinate System of 1983 (SPCS 83). All states defined SPCS 83 with metric parameters. Within the legislation, the U.S. Survey Foot was specified in 11 states and the International Foot was specified in 6 states. In all other states the meter is the only referenced unit of measure in the SPCS 83 legislation. The remaining 19 states do not yet have any legislation concerning SPCS 83.[4]

Since that time, several states have abandoned the non-metric versions of SPCS 83: seven states continue to keep location data in survey feet as well as in meters, while an eighth keeps data in international feet as well as in meters.[5] State legislation is also important for determining the conversion factor to be used for everyday land surveying and real estate transactions, although the difference (2 ppm) is of no practical significance given the precision of normal surveying measurements over short distances (usually much less than a mile). Twenty-four states have legislated that surveying measures should be based on the U.S. survey foot, eight have legislated that they be made on the basis of the international foot, and eighteen have not specified the conversion factor from metric units.[5]"""


Its quite clear that the US is totally undecided and probably confused about how long a foot really is!

Tony

 

[dextrous]

Precisely Tony, so a cubic foot may not actually be a cubic foot.

And until recently, if memory serves me right, a metre was the length of 1 second of arc of the earth's circumference at the equator, until they changed it to a certain number of wavelengths of light (Angstrom????) in a vacuum (the number eludes me )

 

[ColJack]

It shrinks as it gets colder, so it must expand as it gets warmer.

at minus 320c it would be smaller than minus 120c.

absolutely true.. as the solid is chilled the atoms don't vibrate as much so the whole mass gets smaller..
it expands to the point where it melts,. at which point it looses it's crystaline structure that is holding the atoms appart.

for a rough example, take 4 teacups and arrange them on a worksurface so that the handle of one cup is touching the side of the other to form a square..
now turn the cups so that the handles are lying alongside the other cup and push them into the middle..
View media item 14059as you can see the water takes up less room..

 

[dextrous]

It shrinks as it gets colder, so it must expand as it gets warmer.

at minus 320c it would be smaller than minus 120c.

absolutely true.. as the solid is chilled the atoms don't vibrate as much so the whole mass gets smaller..
it expands to the point where it melts,. at which point it looses it's crystaline structure that is holding the atoms appart.

for a rough example, take 4 teacups and arrange them on a worksurface so that the handle of one cup is touching the side of the other to form a square..
now turn the cups so that the handles are lying alongside the other cup and push them into the middle..
View media item 14059as you can see the water takes up less room..

Two observations about your analogy. First is you're not taking into account any water within the teacups Second is that this would suggest that there is an absolute minimum capacity as the atoms could not get any closer.

 

[Dick Puller]

There was many types of single pipe systems installed here in the UK, many of which were on gravity circulation, for example; a single pipe drop system was very common. Most were named after the way they connected the radiators.

When I served my time, I was lucky to work with some old boys that were a fund of knowledge and installed gravity central heating systems in the wilds of the Scottish Highlands. I can hear these old gits laughing from the grave at all you DaftyDIY'ers & CC/CCCs...........

 

[clf-gas]

Water does indeed expand when heated/boiled, as does it expand when chilled/frozen.

Is this a paradox.