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combi boiler

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. W

    Vokera Combi boiler replacement

    My 30 year old good servant a Combi Vokera Flowmatic 20-80 RS has finally given up RIP. Think Vokera don't make them like they used to so not necessarily like for like replacement. Ground floor flat with 5 large radiators and 2 small radiators. As this Combi has served me well I assume it was...
  2. A

    Combi Boiler heats radiators when hot water only is selected.

    My combi boiler has started heating the radiators when I select hot water only. Any ideas ? The system has been in for maybe 10 years.
  3. A

    Combi boiler making a whooshing noise

    Hello, Today a technician came round to check a radiator that wasn't working and turned off all the radiators which fixed the issue. Now the combi boiler is making a continuous noise that seems to be coming from the pipes underneath it. I've turned the boiler off and it's still making the...
  4. gcleve

    Set Worcester combi boiler to circulate without heat.

    Hi there - I have a Worcester Greenstar 25Si combi boiler running our heating rads. I've recently added a small tank with a heating element powerd by solar into the rads circuit. It's producing good heat, but I need a circulation pump to be on to move the heat around the system. Ideally I'd like...
  5. R

    New build heating engineer needs pointing in the right direction.

    Hi, I have a vaillant ecotec plus boiler (pre 2012 model) that is giving me hot water issues. It points towards a hot water heat exchanger issue or diverter valve, but I have replaced the diverter valve (old one seemed to still operate as it should as well) so it would seem that wasn't the issue...
  6. P

    Combi boiler issue or Shower?

    Hi Yesterday my shower in the bathroom started to run cold. It started fine but then ran cold...then got warm again before running cold again. This continued and then just ran cold. Other taps ran hot as usual so thought it could be the shower/cartridge. Instead of fiddling with manufacturers...
  7. G

    Warm flow combi boiler /No hot water

    Need help please... My Warmflow oil fired combi boiler will not supply hot water to my domestic taps but the central heating works fine. This is a dual pump system. I have linked out the connections on the boiler stat which causes the hot water pump and system to work and able to get very hot...
  8. K

    URGENT Worcester Heatslave 15/19 Oil Combi Boiler Pressure

    My boiler pressure gauge is at zero so the boiler is not firing up. I thought I heard a small water leak in the wall near the boiler the other night, just before this happened, but the leak has now stopped. I have been reading other posts to try to find a solution and I've hunted everywhere...
  9. U

    Installers with experience of Hybrid Solar Thermal / ASHP and Combi Boiler in Sussex Area

    Hi, I'm looking for someone to help specify, and possible install hybrid system. Initially the bungalow was setup for all low temp (underfloor heating and Fan assist heating rads), but couldn't afford ASHP at the time, so fitted a Vaillant Ecotec Plus 937 Combi as the heat source. Now looking to...
  10. S

    Shower hot water and flowrate issue (combi boiler)

    Hi, I’m trying to get to the bottom of some issues I’m having in my home (moved here 4 months ago) with the combi boiler and particularly the shower – any help would be greatly appreciated! I’ll explain the issue and the steps I’ve taken so far to try and resolve/understand it. The issue -.
  11. J

    URGENT Ignition issue Main Eco 30 Combi boiler

    Hi All, I have a Main Eco 30 Combi boiler I was fitted about 7 years ago, the whole pipe work is new and radiators. I have so far replaced the electrodes since it was old and bent (it was working but I wanted to avoid it failing), the heat exchanger was hoovered and the seal was replaced, the...
  12. Ryooo

    Heatslave 25/32 No HW

    Hi guys just installed an oil 25/32 external Worcester Bosch Heatslave External boiler. I can't get hot water. Central heating is fine. Comfort rf fitted and seems to be working fine. Link wire has not been removed. The sensor is not registering the dhw lts per minute display. Any help...
  13. S

    Combi boiler. Running CH whilst DHW drained.

    Have a query regarding a morco combi boiler in a mobile home. It's set up with a link on the thermostat connections within the control panel and heat is controlled by Trv's. I'm planning on adding a hive thermostat to give me more control and intend to use the app. My question is, when the DHW...
  14. C

    Cold Electric shower when any tap turned on

    Sorry a slight variation on other posts! I recently moved into a 3 storey semi (new 2017) Top floor, ensuite Electric Shower Middle Floor, Electric Shower and extra shower fittings off bath, WC, Basin Ground Floor. Cloakroom, WC. Washing machine Combi Boiler Problem- Ensuite Shower goes cold...
  15. S

    Do I need to keep the overflow tanks in my loft if I get a combi boiler?

    In my loft I have 3 water tanks. A bigger black one, that I believe is the cold water overflow. A smaller black one, that I believe is the hot water flow, and a big brass tank that stores the hot water I heat. I'm thinking about getting a combi boiler, and I would like to know that if I do get a...
  16. C

    Currently awaiting repair Combi Boiler leaking for 8 years. Is my plumber incompetent?

    Hi everyone, my combi boiler has been leaking for 8 years. It is a german Vaillant VCW 204 The thing is, this device is from...
  17. S

    PRV and condense discharge form a combi boiler

    Good day all, First and foremost i am not a boiler installer or gas registered, therefore i do not touch this element of plumbing, but i am after the correct advise regarding the following issue. I have had a gas installer who has piped the PRV and condense discharge pipe from a combi...
  18. M

    Thermal store combi boiler, hot water flow rate.

    Can anyone tell me the hot water flow rate on a thermal store combi boiler? As opposed. To a 40kw combi that will deliver nearly 16litres per minute. And any recommendations for a good thermal store boiler thanks.
  19. J

    Hot metal/burning smell from combi boiler

    Have some problems with my boiler that cant seem to get fixed. It's a worcester bosch greenstar cdi 30 combi and it's about 5/6 year old I think. So basically the boiler has been making like a burning/hot metal smell. But it seems to only make the smell when the boiler has been like working...
  20. C

    Smart thermostat solution?

    Hi all, I am after some advice with upgrading my control system on my oil fired boiler. Currently I have an trianco Eurostar combi. It supplies heating to all of my house and hot water to half. It has a standard honeywell programmer and 2 wired battery powered wall stat. Hot water for the other...

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