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hot water

Water heating is a heat transfer 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 (Southern Africa only), 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, Finland and Poland. District heating systems supply energy for water heating and space heating from combined heat and power (CHP) plants, waste heat from industries, 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.
Today in the United States, domestic hot water used in homes is most commonly heated with natural gas, electric resistance, or a heat pump. Electric heat pump water heaters are significantly more efficient than electric resistance water heaters, but also more expensive to purchase. Some energy utilities offer their customers funding to help offset the higher first cost of energy efficient water heaters.

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  1. M

    Rayburn plumed into vented hot water tank

    Hi, I have a rayburn 212 that I have plumbed into a vented hot water tank as far as I am aware I do not have to vent the rayburn as the tank is vented, is this correct. attached Is an image of the tank and a very basic schematic, fig 1 is how I have it plumed fig 2 is how I would plumb if the...
  2. M

    Hot water to multiple commercial kitchens

    Hi all, Hope all are well. I’m in the early stages of renovating an industrial unit. The fit out is to have 7/8 commercial kitchens, these kitchens will have reasonable output, i.e. high street takeaway in terms of their demand. The unit has 3 bar of pressure and 25 litres a minute of water...
  3. J

    Hot water leaking at overflow

    Hi Overflow suddenly spouting out luke warm water to outside of house, checked on down pipe in photo leads exterior overflow, could put finger spout when overflowing and its luke warm water. Why is it overflowing? Lot of water coming out. Photo attached of side of tank to show above. What is...
  4. B

    Not hot water in two outlets

    Hi Guys Need to pick your brains if you have a moment. I attended a flat where in one bathroom the hot water on the basin had major low pressure. In the Ensuite shower it was the same issue in the hot water. All the other hot water outlets in the property had good pressure. Bath and kitchen...
  5. G

    studio flat heating and hot water

    asked to specify for very small studio flat, architect has drawn a combi boiler, 2 radiators, heated towel rail and shower, basin, kitchen sink, washing machine. seems overkill to me, in the past i have used electric shower, 15l 3kw Ariston for hot water, and electric panel heaters, but he is...
  6. vrtechsol

    Hot Water system Installations

    Suggest some good hot water system installers and sellers. In Australia
  7. S

    URGENT How to shut off hot water and heating on this kind of boiler and tank?

    How to shut off hot water and heating on this kind of boiler and tank?
  8. W

    Combi boiler - bang when hot water opened

    Hi All! I hope you can give me some advise. I had combi boiler (Viessman vitodens 100-w 30kW) installed about half year ago. Recently I start hearing one single bang when hot water is opened at any of taps around house. It sound like someone in other room will knock a radiator (not relly loud...
  9. S

    Hot water, low-pressure

    Hi today, I installed a new kitchen tap, isolated the stopcock I’m drained down the hot water when turn the stopcock back on the pressure outside the kitchen tap was weaker. Strangely, the bathroom tap has good pressure this is for the hot both colds a good pressure Any advice please?
  10. R

    Hot water turns on radiators

    When the hot water is set to on, the radiators also warm up. Two 2-port valve / cylinder/gas boiler system. Seemed possible likely that the valve to the heating was sticking open (partially?). This valve was replaced the problem remains. What could be other possible causes? When the heating...
  11. D

    5 min of hot water in shower after cartridge change

    Our master bath shower had two shower heads. One was leaking/dripping so our plumber changed both cartridges since he was already there. That fixed the leak, but ever since one side gets too hot and the other side only stays hot for 5 minutes before slowly getting colder and colder. Our plumber...
  12. T

    Y plan provides hot water when turned off

    Customer complained of hot water tank getting hot when no demand Y plan system couldn't see any issues so I watched it Timer set to CH only, HW off Thermostat turned to on Heating comes on as normal, valve moved to CH position After around 20 minutes the 3 way valve moves to mid point and...
  13. M

    Hot water from tap leaves smell on things it comes into contact with

    We’ve noticed a wet dog type of smell on items that have been in contact with hot water from our taps. This doesn’t happen with cold water from our taps. Do you have any ideas what this could be and how the issue can be resolved please?
  14. Eddiez

    Hot water balancing issue

    What position should hot water valve be as my kids have tampered with it and hot water isn't as hot anymore
  15. Tom020

    Hot water back flowing

    Hi, I've got a cold water storage tank which feeds the hot water cylinder below. The hot water is backflowing up to the cold water tank and then overflowing now and again. If i put a non return valve on the cold feed to the cylinder would this just push the water up to the vent pipe? There are...
  16. J

    Hot water tank worth keeping?

    I've just moved into a house with an old Potterton Profile P60e (75% efficient). The hot water tank is currently taking up the space in the bathroom that would be perfect for a shower enclosure. So we have a choice, 1) Upgrade the boiler to a combi, rip out the tank and replace with shower...
  17. I

    Honeywell Evohome hot water control for new boiler

    Looking for a quick bit of advice since I'm trying to wrap my head around what work I need done. Right now I have an old conventional boiler that heats my hot water tank. The water tank has manual open/shut valve so that I can only heat the water tank and not the heating. I'm replacing this...
  18. C

    Hot water service in home

    Please forgive the length of this post, but I must provide all the information to fully explain the issue. I am completely perplexed! My 43 year oldhome is in the country, on a well. Recently, I had a 20+ year old 40 gallon propane hot water heater professionally replaced. The house service line...
  19. M

    Taking hot water feed from expansion pipe.

    I fitting a new Mira shower in a slightly different position in the bathroom. It’s going to be easier to feed it with cold water from main cold cylinder feed and from a connection to the hot water cylinder expansion pipe. These are just above the shower position. the pipes are both 22mm and I...
  20. D

    Where is the water coming from?? Hot water tank keeps dripping....

    Hi all - hoping someone knowledgeable can help as I'm super confused by this.... I have a standard system / gravity fed boiler, large cold tank in attic, hot water tank in airing cupboard etc. I recently found that the hot water coupling into my shower pump (salamander) had sheared (the...
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