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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. jamesa2487

    One Cold Radiator Downstairs

    Hi. I have one radiator downstairs that will just not get hot. If I disconnect the thermostatic valve then turn it on hot water comes through. When I reconnect it the radiator heats up for a couple of days then stops again. I have bleed the radiators / balanced. Any idea? Thanks
  2. B

    Cold Rad's & return cool on another rad

    Sorry I have sort of asked this before, tried professionals but not great 1st experience hence DIY attempt attempt again. 2 completely cold rad's, another one get pretty warm, flow pipe hot, return v.luke warm. (Both rad's I have manually flushed really well) Hot water works fine, boiler return...
  3. B

    Shower going cold, hot water supply gets cut off completely?

    I have a new shower that has worked fine, albeit with low hot water pressure, for a couple of months. Now it starts hot, but then goes cold completely, sometimes after a couple of minutes, sometimes after less than 30 seconds. Meanwhile, on the side of the bathroom sink, there are no issues...
  4. A

    Kitchen tap running hot and cold

    Hi all We have an issue with a kitchen tap it seems to run hot and cold or Luke warm all the the other taps in the house are fine it’s just this one tap. It is a mixer tap and the combi boiler is about 2 metres away. It’s a Worcester greenstar. Is this an issue with the tap itself or something...
  5. F

    Combined vent and cold feed

    Hi guys Is it normal for the cold feed pipe from the f&e tank to be combined with the open vent? The cold feed connects to a 22mm tee one end is the vent the other cold feed to rads I thought the vent connects to ch flow and the feed to ch return? Thanks in advance
  6. V

    No cold water in bathroom.indirect water supply.

    Hi.. I would appreciate your advice. I am not get any cold water on the bathroom. Just dribbles in the bath and toilet..none at all on the wash basin. The supply is from the cold water tank. Thank you.
  7. S

    Window seal and gaps need filling too cold

    My house seems to be freezing and my double pvc glazing windows were installed over 20 years ago. The window seals have seen better days and there's gaps in between the window frames and window. Not really done anything like this before as I am not a plumber or carpenter. Does anyone which...
  8. E

    New column rad cold devastated

    New double panel column radiator Cold Turned off all rads not helped Checked trv pin seems fine Locksheild i think is ok see pic sttached Its new so didnt need to flush Cant really balance because the only thing that is hot is the copper pipes So instructions came with it about how it...
  9. BulkWorkwear

    🥶Best Selling Winter Hats

    Beat the cold weather with our best selling Winter Hats! 🥶 Buy yours here
  10. R

    Cold Radiator - questions regarding valves

    Hi all, I'm hoping someone here can help. The radiators in my living room aren't heating as well as the radiator in bedroom, hall and bathroom in my flat. I've checked and both seem to be free from trapped air (tried to bleed and water came straight out). Now one radiator gets a lot warmer...
  11. Ian Howe

    Cold rad and manifolds

    Narrowed down a cold rad to this manifold, are they prone to blocking or is it more likely the microbore?
  12. V

    New house, 1 cold radiator, I've run out of ideas, help!

    Moved in to bungalow recently and 1 radiator is cold. All the others get really hot when turned on. Gas system boiler, header tank in loft. I tried balancing, turning off other radiators, increasing pump speed, but best I could get at high pump speed is a tiny bit of heat in radiator, barely...
  13. K

    Distance between Hot & Cold pipes?

    Hi all, I was just wondering when running hot and cold copper pipes side by side is there a minimum distance they should be apart according to regulations? Thanks P
  14. D

    Cold radiators!!!!!!

    Hi I turned my heating on few days ago for the first time this winter and bleed the radiators and it all worked fine. Turned it on again tonight and the boiler fires up but all the radiators are stone cold! Any advice on what it could be? The pump in the airing cupboard is pumping
  15. JoeBilton

    Cold radiators balancing

    Our upstairs radiators were getting much hotter much quicker than down stairs. To try and balance I altered some of the lock values on the upstairs rads (not fully closed though) this seemed to work and the downstairs rads were much hotter however one of the upstairs rads was now totally cold...
  16. D

    Radiators hot upstairs and cold downstairs

    I've a pressurised CH system with a combination vented cylinder. I live in a two story house with 4 radiators upstairs and 4 downstairs. I recently had the CH pressurised and the cylinder also was replaced. The problems is that the radiators upstairs are getting nice hot but the ones downstairs...
  17. B

    Some rads cold at the top, and some at the bottom.

    Hi, We had all the rads replaced in the spring. They had this issue from day one but, tbh, I thought once they start getting used in the winter, things might sort themselves out. That hasn't happened. It's a weird situation where some rads heat up only at the top, and some only at the...
  18. K123456

    How far can slab cold water inlet be from shower tap - 1200mm?

    The hole in the slab for cold water shower tap inlet is 1200mm away from where it needs to be. Is this a problem? The bathroom is on the second storey (concrete slab) and it looks like the builders may have put the plumbing for the shower inlet about 1200mm away from where it needs to be. Is...
  19. mjtefc

    10mm not 15mm cold water to fridge

    Divy here thought his cold water feed was 15mm.. so bought a 15mm - 1/4" reducing tee to plumb a fridge. It's 10mm!! I've already cut it so stuck a stop end on. What options do I have as I can't find a 10mm - 1/4" reducing tee... Do I get some 15mm pipe and use 15mm - 10mm reducers ?
  20. S

    If i remove a radiator in the living room will there be a cold spot?

    Hi, We currently have 3 old radiators in our living room, the room feels cold in winter and radiators take ages to get warm, system has been power flushed and new pump fitted, so want to replace the radiators. The room is 5.7 x 4.9m x 2.5m but heat vents upstairs to a landing with no radiator...
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