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hot water

Water heating is a thermodynamic process that uses an energy source to heat water above its initial temperature. Typical domestic uses of hot water include cooking, cleaning, bathing, and space heating. In industry, hot water and water heated to steam have many uses.
Domestically, water is traditionally heated in vessels known as water heaters, kettles, cauldrons, pots, or coppers. These metal vessels that heat a batch of water do not produce a continual supply of heated water at a preset temperature. Rarely, hot water occurs naturally, usually from natural hot springs. The temperature varies with the consumption rate, becoming cooler as flow increases.
Appliances that provide a continual supply of hot water are called water heaters, hot water heaters, hot water tanks, boilers, heat exchangers, geysers, or calorifiers. These names depend on region, and whether they heat potable or non-potable water, are in domestic or industrial use, and their energy source. In domestic installations, potable water heated for uses other than space heating is also called domestic hot water (DHW).
Fossil fuels (natural gas, liquefied petroleum gas, oil), or solid fuels are commonly used for heating water. These may be consumed directly or may produce electricity that, in turn, heats water. Electricity to heat water may also come from any other electrical source, such as nuclear power or renewable energy. Alternative energy such as solar energy, heat pumps, hot water heat recycling, and geothermal heating can also heat water, often in combination with backup systems powered by fossil fuels or electricity.
Densely populated urban areas of some countries provide district heating of hot water. This is especially the case in Scandinavia and Finland. District heating systems supply energy for water heating and space heating from waste heat from industries, power plants, incinerators, geothermal heating, and central solar heating. Actual heating of tap water is performed in heat exchangers at the consumers' premises. Generally the consumer has no in-building backup system, due to the expected high availability of district heating systems.

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  1. L

    Scalding hot water!!

    Hi there, I've just moved into a new home, prior to this the previous owner installed a new boiler a "baxi ecolbue 16kw heat only". My previous home had a nice easy to use valiant combi which was simple to use, with my new set up having a water tank, pump and timer i'm struggling to keep the...
  2. G

    Banging hot water pipes

    Hi, I have recently had a new bathroom fitted and ever since my hot water pipes clatter when it reaches it's temperature and shuts off the boiler. I don't believe it is due to the work that's been done but possibly due to the system being drained several times? Thanks in advance for any advice.
  3. S

    Boiler move with Gravity hot water

    Hi all first timer here...I need a bit of advice on a central heating job..the job is for a relitive who gave me a call wondering if I could move an oil boiler from the utility room of his house to the corner of the garden he wanted to buy a new condensing oil boiler that can be fitted...
  4. R

    Problem with hot water on logic combi 35

    hi Gents We are having issues with constant hot water flow with the above boiler. The boiler was serviced over a year ago and had the same issues , at that time the plumber thought the issue was the thermistors and they were changed. This seemed to help the problem but did not cure it and it...
  5. M

    Leaking hot water pipe in concrete. Replacement advice needed!

    Has anyone come across anything similar. Sorry there are so many questions. Many thanks in anticipation. My daughter has moved, 5 weeks ago. The previous owners had a hive system on the Worcester-Bosch combi boiler. They replaced it with a hive thermostat and my daughter eventually got it...
  6. M

    Heating and hot water keeps turning on and off please help

    Having problems, heating and hot water turn on then off then on over and over. I am a totally unqualified but have a bit of sense. When it goes off our "honey we'll st9400c" goes completely blank, then seconds later it turns on again, over and over. I have noticed a red contraption which I think...
  7. E

    Hot water tap in kitchen has low flow, but the bathroom hot tap flow is fine

    I have been having trouble with my hot water tap in the kitchen lately. The flow rate had been dropping over the past few months to the point where it completely stopped running at all. My boiler is an old hot water cylinder, so water pressure is essentially not meant to be great for the hot...
  8. A

    No hot water but rads hot on combi

    Potterton gold 24he. Changed DV, actuator motor, magnetic flow switch & descaled secondary heat change. What else could it be!?!? Before doing this shower was just getting hot and cold. Thanks in advance
  9. J

    Black bits that smear in hot water

    Hi guys, We've got a combi boiler system that was last serviced 2 years ago. For the last year or so we've been getting black specks coming through in the hot water when we run the bath. We haven't noticed them in any cold water outlet or hot water in any sinks. At first we thought the issue...
  10. B

    recurring airlock in hot water feed to shower pump

    Hi everyone, I thought I had solved my previous issue - posted here: recent hotwater pressure drop to shower pump - help! Up until a month ago, I have had good strong pressure in the shower with plenty of hot water and then one morning a major loss in pressure. Pump is fine (it's a 2.5bar...
  11. A

    Vented hot water problem

    Hi everyone, Recently my central heating system has developed a problem. When the system is on and just calling for hot water the boiler lights and runs for 1 to 2 mins and gradually starts kettling before cutting out. Once it has cooled a bit it cycles and does the same again. If it is...
  12. L

    Help request - shower hot water cutting out

    Hi there Looking for some help please. We have a Triton T300si. We had a leak in the remote unit. Plumber said it was a problem with the stabiliser so we bought a new one and plumber replaced it. There is a new problem now. When the shower is switched on, after a few seconds the hot water...
  13. K

    HELP: Pressurised/Unvented cylinder - No hot water, central heating works fine

    Problem: No hot water from unvented cylinder, although central heating works fine. Hi All - apologies for the lengthy post but I'm keen to get across as much detail as possible. I'm a novice, any advise would be really appreciated. Setup: Pressurised/unvented cylinder (Tempest) System Boiler...
  14. N

    What causes noisy hot water tank filling up?

    Just started recently - sound like a 'whirr' when hot water tank fills up after hot taps used for a few minutes or after a shower. I don't think anything to do with Potterton boiler as the noise happens when the boiler isn't on - for either water or heating. The noise seems to be from the cold...
  15. S

    New hot water system for Victorian Terrace.

    Hi, looking for some advice on the best hot water system to use in our 3-bed, 2 floor, Victorian Terraced house. The current set up is with a conventional boiler in the utility room, a hot water vented cylinder in the first floor airing cupboard with an electric pump for the shower, and a cold...
  16. G

    Hot water tank question.

    Hello everyone. I am looking for a bit of basic advice on hot water tanks. I currently have a warm air heater that heats up the water in my tank via a heat exchanger. The tank is now very old and does need sorting out. I am getting a brand new, unvented tank as a replacement, with an immersion...
  17. V

    Unvented heating and hot water

    Hello all I'm installing an unvented vaillant unistor cylinder. The parts in the box includes a single two port valve. Thing is there is no 3rd party wiring diagram in the installation manual showing how to wire this two port valve into a y plan system. Has anyone got that diagram? I have...
  18. A

    Boiler not registering a hot water tap being turned on.

    Hi All, Before we start I will admit that I am a total novice when it comes to plumbing but before I call someone out I want to try and see if it is something simple. I have a triton mixer shower and when the tap is turned all the way to hot it doesn’t effect the temperature at all! It remains...
  19. B

    Hot water cylinder substance in side?

    Hi there plumbers. I'm not a qualified plumber myself although I do reluctantly do it at home. Random query here. I ripped out an old cylinder from my 40s house and replaced everything with a combi (which was done by a certified engineer of course). I've now finished the house so going to do...