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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. R

    Advice on Combi Boiler

    Hello - I was hoping for some advice and opinions on a new combi boiler I currently have a 3 bed semi with a myson orion boiler (it isnt a combi) - the boiler was installed around 1989, hasn't given any problems and is still working fine. Due to the increase in gas prices it is time to change...
  2. S

    UFH/Rad combi boiler & Weather compensation

    Hello all I have a Worchester Bosch greenstar 32CDi combi with an S plan, 3port for UFH downstairs (4 zones) via manifold & mixer valve, & upstairs 4 rad system, with towel radiator always open for a bypass. I have a full tado system that is basically set to relay on/off when any thermostat...
  3. N

    Combi boiler flue leak

    Hello, I have a Vaillant Ecotec combi boiler. The flue pipe extension has started to leak at one of the joints. The internal plastic connection pipe appears to be intact. It still drips when there isn't a demand for the boiler. I've attached some pictures and moved the joint strap to see...
  4. D

    Parallel System wood burning stove and Combi boiler

    I'm looking for a heating engineers/old school plumber to put in a Combi boiler (possibly Intergas) replacing very old open vent system in parallel with a wood burning stove with a back boiler (ESSE Bakeheart) as back up and alternative. I know this relies on two radiator systems. Combi for...
  5. O

    Why does my perssure keep going up?

    Any idea why the pressure keeps going up on my combi boiler? I have a Vaillant Ectotec Plus about 15 years old. The heating has been off all summer and the filling loop taps are both fully closed but the pressure keeps going up. I empty about 2-3 litres of water from the system every 2-3 weeks...
  6. Renier

    Do Combi Boilers only provide hot water at 100% Open Tap?

    Recently had boiler issues heat exchanger was replaced but water would still go Cold Randomly especially in the shower. Engineer says Combi boilers can only provide hot water if the turbine is spinning at max speed so you have to open the tap at 100% to get hot water. So he removed(broke) the...
  7. Y

    Combi Boiler Internal Timer Replacement With Hive

    My son has just got his first flat and want to install "Hive" heating control. I've done this a couple of time with an external controllers but the fact the wirings all internal has made me wary of doing it my self. I want to know if I should take wiring from the back of the mechanical timer...
  8. M

    Help: Choosing the Best Combi Boiler for a Shower

    I'm considering changing our current Conventional/Regular Gas boiler, to a Combi. The main reason for doing this, is so that I can run a more effiecent shower. eg: With a better temparture control, combined with a better flow rate. But in order to get a combi with a good hotwater...
  9. 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...
  10. 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...
  11. 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...
  12. 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...
  13. 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...
  14. 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...
  15. 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...
  16. 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...
  17. 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...
  18. 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...
  19. 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...
  20. 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
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