From the United States of America? - Checkout our specific plumbing forum for you:USA Plumbing Forum

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.

View More On Wikipedia.org
  1. J

    Combi boiler advice for 2 showers on same time

    Hi, First post and, it may be a long one (sorry title looks a bit naff as well but...) Getting a new bathroom fitted and the old one replaced, it currently has a mixer shower attached to the bath. I also have a small en suite with another mixer shower (b & b), both are on the first floor...
  2. A

    Recommendations for new combi boiler install

    Hello, I'm looking for advice on replacing a back gas fired boiler with a new combi boiler. I was thinking of placing the new combi boiler in the store room where the mains gas meter is located. Been looking a Worcester Greenstar 32CDI compact combi boiler but really looking for recommendations...
  3. T

    combi boiler not kicking in

    Hi all, i'm relatively new to the world of plumbing and bathroom fitting. I've recently fitted a bathroom and the new basin tap (Bristan Orta Mixer) wont kick in the boiler when the hot is turned on. The new bath mixer and the existing kitchen tap work fine although the hot has to be turned...
  4. J

    Bosch CDI 30 combi boiler

    Hi, my boiler has been having an intermittent fault no one can seem to cure. When the hot tap is used , usually first time in the morning, it creates the boiler to over heat. I have to wait for it to reset itself and cool down then usually ok. Apparently not heat exchange plate.
  5. N

    System or combi boiler?

    Hi guys We want to do a whole revision of our boiler system- we currently have a system boiler at the moment with a water tank upstairs. One bathroom currently with electric shower and a 2nd bathroom still being constructed. What do you guys advise? Please let me know if this is in the wrong...
  6. marcuspreedy

    No DHW from combi boiler

    Hello I am having to replace the unvented hot water system in my property, and as a temporary measure to get DWH downstairs I have un-isolated the supply from my Grant combi boiler. But, no hot water is forthcoming! I think it may be a problem with the Danfoss set3e programmer which a builder...
  7. J

    combi boiler, pressure continuously increasing.

    Hi, I have a vaillant ecotec plus 837 and one day noticed the pressure was maxed out therefore bled the radiators to drop it down to 1.2~1.4 bar. Two weeks later, I noticed my pressure increased back up 2.5 bar so had to bleed the radiators again. A guy at work told me the increase in...
  8. D

    What is this error code on Bosch combi boiler?

    I've been having problems with my boiler since I moved house. Today my Hive thermostat was offline, then it recovered but after that my boiler's central heating had problems starting. I've reset the boiler AND turned it off/ on and despite that I am getting the above error - which I cannot even...
  9. T

    Hi.. and a combi boiler pressure drop query!

    Hi Just joined forum as amateur DIY guy and wonder if anyone here can help me. I have a Vaillant 828 Turbomax Combi boiler which I’ve had for about 16 years old. I monitored the pressure yesterday & saw that it was quite low (around 1) so I topped it up to just over 2 and when I went back to it...
  10. J

    Combi Boiler Size advice

    I'm looking to have a Combi Boiler installed along with 8 Radiators in each room along with a Towel rail in the bathroom. I wanted to check with people what size combi boiler people think I need as I have had one company who has quoted me for a Worcester green star 28cdi compact boiler and have...
  11. A

    Combi boiler firing noise

    My combi makes a noise when firing up, rather like a "whoof"sound, and a but louder than it used to. Can anyone other any advice as to what the problem is of if there is one? Thanks in advance
  12. J

    Intergas HRE 28/24 Combi boiler on Melamine/Ply board?

    Hi all, I have tried to email Intergas about this and they still haven't got back to me!! I have a plumber installing a new boiler and want to know if i need to remove the melamine board the previous boiler was on and fit a ply board then cover with plasterboard to get over the combustible...
  13. L

    Back up to combi boiler

    Hi I went to a landlords today and the guy who had installed the combi boiler (in loft) had hooked up Red ring power stream 10.8kw instant water heater as a back up to the combi boiler. It was isolated and drained whilst the combi was working, and connected in a similar way you would by pass a...
  14. D

    best replacement combi boiler ?

    want replace worcester 35cdi combi have 12 rads, 2 showers, which boiler best replacement?
  15. M

    Combi boiler: water pressure question.

    My son recently moved house;...the CH boiler is an Ideal Logic Combi ES30 and it’s about 2 or 3 years old. When the system is cold the water pressure shows approx 1.9 bar,...when the CH has been on for a while and everything is fully heated-up the pressure gauge rises to approx 2.9 bar. If the...
  16. L

    Potterton Combi Boiler Frequent Pressure Loss in Winter only

    Hi, My Potterton Heatmax Boiler is nearly 10 years old, but has been serviced regularly and the Pressure Release Valve was recently replaced. It frequently loses pressure throughout Winter, when the heating is in use. During Summer months, it's fine! All radiators are all heating up to HOT and...
  17. S

    Help... Combi Boiler or Unvented system

    Hi, just moved into a new house and have a 25 year old heat only boiler, 114ltr hot water cylinder with central heating pump. Noisy and not efficient. It’s a 4 bed house with two bathrooms. Main one has bath and shower and second one has a shower. Flow is 16 litres minute and 2.3 bar pressure...
  18. C

    Trianco Eurostar combi boiler going off

    Morning all, Can anyone shed some light on said boiler? It’s going off on unexpectedly. This is only the second time it’s done so in 3 weeks, boiler doesn’t go in to lockout. The first time was just after having heating oil tank topped up, but far as I can see oil is flowing freely to pump. The...
  19. W

    Potterton Titatinium 33 Combi Boiler - Hot Water Issues

    Potterton Titatinium 33 Combi Boiler I’m having issue first thing in the morning where the hot water is failing to fire up, the hot water gets stuck around 37/ 38 / 39. A few things to note: The hot water takes a while to fire up and start to get warm. Only happens very early in the morning...
  20. P

    Worcester combi boiler cutting out on hot

    Replaced a bath tap with shower attachment and Fitted a Aqualisa Midas thermostatic bath /shower mixer . During the shower sometimes the water goes cold for a few seconds and goes warm again and customer said the boiler is cutting out then coming back on when it does this . Almost like it’s...
Top