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combi boiler

Tankless water heaters — also called instantaneous, continuous flow, inline, flash, on-demand, or instant-on water heaters — are water heaters that instantly heat water as it flows through the device, and do not retain any water internally except for what is in the heat exchanger coil. Copper heat exchangers are preferred in these units because of their high thermal conductivity and ease of fabrication.
Tankless heaters may be installed throughout a household at more than one point-of-use (POU), far from or without a central water heater, or larger centralized whole house models may still be used to provide all the hot water requirements for an entire house. The main advantages of tankless water heaters are a plentiful, practically limitless continuous flow of hot water (as compared to a limited flow of continuously heated hot water from conventional tank water heaters), and potential energy savings under some conditions due to the use of energy only when in use, and the elimination of standby energy losses since there is no hot water tank. The main disadvantage of these systems are their high initial costs (equipment and installation).

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  1. A

    Pipe size length bends junctions to Combi - affect on water flow rate?

    Hello! Advice required, please. Trying to understand implications of pipe size, length of run, and number of junctions etc. en route between the incoming water feed to the Combi-boiler. For various reasons it is difficult to get from stopcock to boiler without taking indirect route back across...
  2. M

    Combi boiler venting into neighbouring driveway

    Hi all, I really hope someone can help me because it is causing so much worry! I bought my house 3 years ago and didn’t know at the time that the boiler was venting out against regs into our neighbours driveway. Our house has a garage conversion so is right up to the boundary line, and the...
  3. N

    Hot water on constantly vaillant ecotech 30 combi boiler

    I notice last night my boiler cupboard was really hot from the hot water pipe, but my husband had just had a shower. This morning it was still hot when we first got up and we noticed the tap symbol was flashing. This is supposed to flash when using the hot water. We've tried turning off...
  4. N

    Baxi combo boiler leak from DHW when not used for 5-6 hours

    Hi I have a BAXI NETA-TEC COMBI 33 GA boiler and every morning I come down to a small puddle of water underneath the boiler. The gas engineer has replaced two washers in the DHW and a new baxi brass adapter and tightens all connections, still the leak remains. It does not leak when the hot...
  5. P

    Programming instructions for obsolete combi boiler timer

    Just moved into the house, previous occupant has lost boiler timer instructions. It's a Worcester Bosch 28Cdi combi boiler, with electronic timer number 77161920030. This timer is obsolete, can't find any instructions online, Worcester Bosch have not replied to repeated emails. There are many...
  6. J

    Drain down a Worcester Hi-Flow 550cdi boiler

    Hi, I have the boiler as above which has been very good for the last 13 years or more and is still relatively going strong. However, now, the secondary heat exchanger is kettling and the easiest option is to replace it. Although Worcester Bosch do sell a cleaning kit, whatever route I take, I'll...
  7. J

    Advice combi boiler plumber says can't fix expansion vessel/access it?

    Hi there, I was wondering if anyone could advise if I should get a different plumber for a 2nd opinion. Basically, my combi boiler is in my attic. It is overpressurised at the moment and the overflow pipe always drips. I had a plumber round, he seemed good and honest and knew the neighbour so...
  8. C

    Removing cylinder and installing combi boiler. Pipe work query

    I have a question regarding combi boiler installation. I’ve just completed an attic bathroom where the previous plumber had put in the first fix of qualpex down to the airing cupboard which is standard practice. I’ve come a later stage to finish the bathroom but I now find that in the airiing...
  9. C

    Expansion vessel for potable water for a combi boiler

    Hi,a customer of mine has a combi boiler and they don't have an expansion vessel for the potable hot water supply. I know there's an expansion vessel for the closed-loop central heating circuit but I doubt the combi boiler has one for the potable water. I was thinking to put one in the airing...
  10. G

    Is this combi boiler installation within safety regulations?

    I am unsure what are the regulations as to how close the pipework coming out of the bottom of my combi boiler can be to the electrical fuse spur? Also, how close can the magna flow be to the electric cable? At present water drips from the pipes coming out of the bottom of the combi boiler onto...
  11. M

    Single pipe system new combi boiler

    Hi everyone. I’m a homeowner, in essence when we moved in we weren’t aware that our house was a single pipe system we have now found out after the water cylinder has packed in and developed a leak. We have had a Heating engineer round who has advised us to fit a combi boiler doing away with the...
  12. A

    Do you have balance hot and cold water pressure with a combi boiler?

    So getting a digital shower and it says the hot and cold water should be balanced. Am I right in thinking they should already be balanced with the hot taking on the cold pressure entering the boiler or am I way off? Cheers
  13. M

    Baxi Combi Boiler (Duo Tec) - water not heating

    Hi all I’m having a problem with my Baxi combi boiler and wondering if anyone is able to help. In short, the water isn't heating. A few months ago (c.2 months) my Baxi combi boiler had an issue where the hot water would go hot and cold on a regular cycle; it would get hot, then cool down, then...
  14. T

    Combi boiler flame loss during current windy weather

    Hi, I have an ideal logic plus combi boiler that has been working fine for all of winter. With the recent storms when the wind speed starts getting up the boiler keeps cutting out with a "Flame loss" error. It'll reignite first time no problem and then continue until a large wind gust then...
  15. D

    Nest connections to electric combi boiler.

    Hi, I moved into a house with a Trianco Maxi Aztec wet electric combi boiler. The system is too expensive for us to run, so we are removing in 3/4 weeks. Aside from being too expensive, it is not running correctly... We have to call for hot water about 25 minutes prior to use (this is not a...
  16. Pgor68

    Combi boiler pressure at 3bar

    Hi all. I have recently drained system, removed all rads and manually flushed them all. Filled system back up, bled all rads and repressurised the system to between 1 and 1.5 bar. The system was off all night waiting for the timer to kick in and when I checked in the morning, before it came on...
  17. O

    Where's my leak? They say not the boiler, but I am not so sure.

    Hello, Can anybody please advise. For months now our old Ideal Mini HE C24 (combi boiler) has had pressure problems. It won't stay above 1 bar. Occasionally I top it up, to above one bar, twice in a day, other times if I am happy to leave it about a 1/3 of a bar it won't complain for a week...
  18. F

    Your opinion on this combi boiler installation

    Hello. We recently had a combi boiler installed to swap out old plumbing sustem with water tank and gas cylinder. You can see end results in the photos. I would like to ask for your opinion on how well this has been done as I was originally promised only two little pipes coming down from the...
  19. A

    Combi boiler pressure

    Hi I suspect I have a leak in my central heating system. Have to refill it every 3 months when the pressure drops below the operating level. Replaced prv and pressure vessel as that was faulty but still having the same problems. More than will to pay someone to come round . I’m in Orpington Kent...
  20. R

    combi boiler pressure bouncing only when hot water is being used

    Combi boiler pressure bouncing only when hot water is being used , could this be the diverter valve diaphragm..... cheers Rob
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