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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. 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...
  2. 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...
  3. 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...
  4. 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...
  5. 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...
  6. 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...
  7. 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...
  8. 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.
  9. 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...
  10. 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...
  11. J


    Hi all, Over the last month we noticed water coming out of all the hot taps and shower would only come lukewarm. The puzzling thing is control unit states that the temperature in the unvented cylinder is at 69-70 degrees celsius. When I’ve I released water directly from the cylinder and felt...
  12. S

    Can one inactive radiator impact combi boiler operating pressure?

    Ideal C34 combi boiler, operating pressure dropping slowly but consistently. All active radiators regularly bled. However we have one radiator with TRV set to 0 (we don't want it come on) and this is never bled. Could this be impacting the boiler pressure and should we still bleed this rad? (Be...
  13. B

    hot water on combi boiler setting query

    Good morning, I have a query about the water dial on my boiler bought a few months ago (Vokera Easi-Heat Plus 25C Boiler) and apologies for no pictures. My hot water is fed via the combi boiler and cold water is mains fed. There are two dials under the flap one is for hot water and the other...
  14. eagleeye

    Combi boiler producing milky slimy water

    We recently installed a new Gloworm combi boiler in a property and we had a call from the customer to say that when he runs the hot water it comes out a milky colour and feels slimy. Also when he runs the cold tap the boiler fires up and then goes off. This is happening at every outlet. Even...
  15. S

    Im looking for an Old boiler case

    I am looking for a case for a worchester 240 combi boiler. The part is obsolete now but I would be happy to buy one if someone is renewing an old boiler and come across an old worchester 240.
  16. S

    Combi boiler whistling

    Hello, I have a potterton promax combi boiler which has developed a whistling/kettling sound when turning on the hot tap. The sound seems to reduce has the tap is slowed. I have also noticed this sound occurs when the boiler is turned off and the tap is running?? I can reduce the noise by...
  17. Z

    Earthing requirements for combi boiler linked to LPG bottles.

    I have 2 lpg gas bottles outside the barn with new combi boiler inside. my entire plumbing inside the cottage is now redone in plastic apart from feeds to the boiler. the boiler is close to a sink Can anyone suggest what earthing I will require and is any earth bonding required under the...
  18. M

    Old baxi bermuda to combi boiler cost help!

    Hello all and thanks for letting me post this question in your forum. I have just had a quote in of £5,700 to replace our old baxi bermuda back boiler with a new baxi 800 combi boiler. All pipework in the property would be changed and along with nine radiators. Decommision and remove the old...
  19. J

    Adding second DHW to Baxi combi boiler

    Hey guys, Just after a bit of advise if something can be done and if so how complicated it would be... I currently have a Baxi duo Tec combi 28 he a boiler which runs the central heating for the house and hot water for down stairs. We are currently ripping out our upstairs on suit to re-vamp...
  20. G

    Combi boiler making noises and pressure gauge jumping, when hot water is turned off?

    Hi, I am just after some advice on my Glow worm Combi Compact 80e. Background- The boiler started to drop pressure a few weeks ago and required occasional topping up. I searched everywhere I could for leaks on the rads,[pipes etc. Nothing found as yet. It got worse and I consulted a combi...