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Cold is the presence of low temperature, especially in the atmosphere. In common usage, cold is often a subjective perception. A lower bound to temperature is absolute zero, defined as 0.00 K on the Kelvin scale, an absolute thermodynamic temperature scale. This corresponds to −273.15 °C on the Celsius scale, −459.67 °F on the Fahrenheit scale, and 0.00 °R on the Rankine scale.
Since temperature relates to the thermal energy held by an object or a sample of matter, which is the kinetic energy of the random motion of the particle constituents of matter, an object will have less thermal energy when it is colder and more when it is hotter. If it were possible to cool a system to absolute zero, all motion of the particles in a sample of matter would cease and they would be at complete rest in this classical sense. The object would be described as having zero thermal energy. Microscopically in the description of quantum mechanics, however, matter still has zero-point energy even at absolute zero, because of the uncertainty principle.

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  1. T

    Megaflo cold feed hammering.

    Afternoon all, I’ve recently started getting a loud vibration coming from the cold feed. Only when I’ve got the hot tap on. Any ideas what it could be? I’ve managed to stop the vibration by turning the blue valve slightly. Thanks in advance.
  2. Bazza1687

    Shower runs cold when hot taps used

    Hello, I have just installed a new shower which works well, however if you open a hot tap anywhere else in the house the shower runs cold, however if I open a cold taps the temperature does not change. I believe my shower is only a mixer not thermostatic did not do my research when buying the...
  3. P

    Heatpump Hot on Gas Side But Cold On Wet Side?

    Mitsubishi Ecodan 2011 8.5kw Hy Guys, I have just installed a second hand ecodan, all seemed to be going well until i noticed that the flow temp doesn't increase much, infact 2 degrees in 40 mins, then the pump shut off with a over temperature warning on the gas side. I have it piped up to a...
  4. J

    radiators cold at the bottom

    Our newly bought house doesnt have a filter on the combi and most of the radiators (microbore) dont heat up at the bottom which im putting down to sludge and other gunk i intend to fit a filter (not sure which 1 yet) and run some clearer through it (fernox f3 has been recommended) i am also...
  5. W

    URGENT Why does my shower keerunning hot and cold

    Why does my shower keep running hot and cold
  6. K

    new boiler just in, HW from shower goes cold after (5-10 mins),

  7. RichardWoking

    Cold water overwhelming hot to showers

    Recently 2 of my showers stopped producing hot water following a plumber refitting another of my ensuites. The 2 showers in question are pumped with a Salamander twin house pump. Hot is reaching the showers (hot feed to mixer is hot), yet both showers are luke warm, at best. The other recently...
  8. J

    To insulate both hot and cold pipes?

    Hi all, I just learned the external pipes for boiler system should be insulated especially in loft and garage as they are in very cold area. I checked my loft and found some pipes are insulated but others are not! I think it is because the insulated pipes are from previous owner's, since I...
  9. M

    Grohe shower unable to get warm/hot

    Hi My daughter has a Grohe mixer shower (see photos) and however I try to mix it to warm / hot it only just manages slightly warm or cold. I don't know how old it is as it was already fitted when they moved in. Can anyone suggest what might be the problem. Other showers are fine so I think it's...
  10. A

    Capping old hot and cold pipes

    Looking for some opinions on whether you should cap old hot and cold water pipes. A plumber I got to remove some old sinks from bedrooms has capped off the hot and cold pipes under the floor. I thought it didn’t quite seem like the best thing to do and thought he would completely remove the...
  11. F

    Hot feed from twin pump stalls when cold feed starts in bath mixer tap

    Hello All, Hoping for a bit of advice/info in this one: My Setup Small system in apartment with cold tank above hot tank in the hotpress, so fairly low head pressure. Installed a pump about 15 years ago and worked fine until last week (original pump was an Stuart Turner ST55 replaced after...
  12. Y

    Two cold radiators, rest fine, balancing doesn't seem to help

    Hi everyone, I have CH with a system boiler with a header tank and 8mm micro bore pipes to the radiators, fairly standard setup I guess. House is 1990s. My issue is that two of my radiators are cold, while the rest are perfectly fine. Both the problem radiators are downstairs and close...
  13. R

    Hot water coming from cold water taps

    Have got hot water coming from upstairs cold water taps. Nothing has been recently changed or adjusted. System boiler connected to Heatrae Sadia CL210 unvented cylinder. Anyone got any ideas as to what could be causing this?
  14. L

    Boiler high pitched noise in cold weather?

    Hi, can anyone help me resolve this issue with my ideal logic combi Esp1 35. It is making a very loud high pitched noise whenever the outside temperature is cold, when either CH or HW is being used. For example, first thing in the morning on a cold day, run hot tap or turn up CH stat and the...
  15. T

    Sweating cold water pipes

    I have sweating cold water pipes, even though I have insulated them with foam it's still sweating. Any ideas what I can do next?
  16. J

    How to convert current mixer valve tap to a cold water supply inlet.

    Any plumbers can advise the best way to convert the current mixer valve tap to cold water supply inlet for electric shower. I have mixer valve tap , I would need to install a new electric shower on shower area wall .Currently is the mixer valve tap. I want to know how to do before I ask the...
  17. D

    Why does shower pressure keep going up and down and hot and cold

    Can anyone please help. We have shower issues and have had for about 2 years. We are in a farmhouse. So before hand, we would turn on our Trevi shower, it would go warm, not great pressure through the showerhead though, somewhere between normal and dripping! After a few minutes, the water flow...
  18. B

    Shower keeps going hot & cold?

    My shower keeps going cold then stays like that for a couple of seconds then goes back to hot & this will keep happening the whole time while showering. It was happening on my previous shower mixer which I then changed to the Mira one I now have & it stopped doing it for a while but now it’s...
  19. R

    Dripping Quarter Turn Cold Water Kitchen Sink Tap.

    I have a quarter turn cold water kitchen tap that has a slight drip and cannot see if the valve assembly is removed from the top? ---- there is a blue plastic cover in the top but does not seem to come off?.......... have photos of tap if anyone can help?.
  20. M

    My radiotor gets cold after 10 minutes

    One of my radiators which is the biggest one in the living room gets hot at first and I can hear the water flow but after 10 minutes the water flow stops and the radiator gets cold. It has the trv valve and I have to put it close to 4 in order for the water flow to start. The retun valve is...