Extending Hot Water Feeds to New Extension

Discussion in 'Plumbing and Central Heating' started by leevis, 26 Nov 2021.

  1. leevis

    leevis

    Joined:
    2 May 2007
    Messages:
    566
    Thanks Received:
    4
    Country:
    United Kingdom
    Hi

    I have recently built a kitchen and have extended the central heating into it and it works fine.

    The problem i have at the moment is the hot water to the taps. I extended the existing run from the existing kitchen (at the back of the house) to the extension and the hot water does not seem to reach the tap. If i turn the tap on in the existing kitchen it will come out hot, but not without.

    Ultimately the old kitchen will be decommissioned, and the pipes to the existing taps capped off/removed and i am worried that i will not be able to get hot water into the new kitchen.

    Is there anything i can do, pipes are under the floor and under units.

    Lee
     
  2. Sponsored Links
  3. leevis

    leevis

    Joined:
    2 May 2007
    Messages:
    566
    Thanks Received:
    4
    Country:
    United Kingdom
    PS this is a combi boiler
     
  4. Madrab

    Madrab

    Joined:
    4 Oct 2012
    Messages:
    8,560
    Thanks Received:
    2,481
    Location:
    East Renfrewshire
    Country:
    United Kingdom
    When you turn the new hot tap on, does the boiler fire up and run?
     
    • Like Like x 1
  5. gas112

    gas112

    Joined:
    27 Oct 2009
    Messages:
    23,035
    Thanks Received:
    8,236
    Country:
    United Kingdom
    What make and model combi, did you run new pipes in 15mm copper or plastic. Small flexes to taps? Standard ballofix valves for isolators and not full flow ones
     
  6. leevis

    leevis

    Joined:
    2 May 2007
    Messages:
    566
    Thanks Received:
    4
    Country:
    United Kingdom
    New pipes are in plastic
    Flexes are 30cm I think
    I used Speedfit isolators which I do not believe are full bore (at least not marketed as such)
    Boiler is a Baxi 105e I think
     
  7. Madrab

    Madrab

    Joined:
    4 Oct 2012
    Messages:
    8,560
    Thanks Received:
    2,481
    Location:
    East Renfrewshire
    Country:
    United Kingdom
    :rolleyes:
     
    • Like Like x 1
  8. gas112

    gas112

    Joined:
    27 Oct 2009
    Messages:
    23,035
    Thanks Received:
    8,236
    Country:
    United Kingdom
    Baxi 105e do a search on here for water venturi that will be your problem it will have fell apart and need changed 15 quid part
     
  9. leevis

    leevis

    Joined:
    2 May 2007
    Messages:
    566
    Thanks Received:
    4
    Country:
    United Kingdom
    Funnily enough I had that exact part replaced about a year ago when there was no hot water in the shower. Shower is still working though/? Could it be the same thing?
     
  10. Sponsored Links
  11. leevis

    leevis

    Joined:
    2 May 2007
    Messages:
    566
    Thanks Received:
    4
    Country:
    United Kingdom
    Ive not checked the boiler firing up yet, I would guess that it doesn't though tbh
     
  12. PlumbBob

    PlumbBob

    Joined:
    30 Dec 2003
    Messages:
    32
    Thanks Received:
    1
    Country:
    United Kingdom
    Combi’s sense the flow and use that as a demand for heat - run may be too far / pipes too resistive to the flow to be enough to meet the threshold to trigger the demand? Just a thought.
     
    Last edited: 27 Nov 2021
    • Like Like x 1
  13. leevis

    leevis

    Joined:
    2 May 2007
    Messages:
    566
    Thanks Received:
    4
    Country:
    United Kingdom
    Just checked the boiler, does not go on when the tap is on. This one is approx 6m away from the one that does turn the boiler on.

    There is another tap going in about 2m from the original, I've just put the sink in but need to sort the tap out will be interesting to see if that triggers the boiler

    Could it be the valves that I have used I wonder?
     
  14. MJN

    MJN

    Joined:
    30 Apr 2008
    Messages:
    757
    Thanks Received:
    117
    Location:
    Wiltshire
    Country:
    United Kingdom
    What's the flow like at the new tap compared to the old? Time the filling of a know-size bucket. As others are suggesting it sounds like a flow-detection issue but before you blame the boiler or tap/plumbing it'd be worth ensuring the new tap (and plumbing to it) is drawing adequately to rule it in or out.
     
    Last edited: 27 Nov 2021
  15. leevis

    leevis

    Joined:
    2 May 2007
    Messages:
    566
    Thanks Received:
    4
    Country:
    United Kingdom
    Ill get a bucket and time it, i would suspect its lower in the new one but will check for sure
     
  16. Madrab

    Madrab

    Joined:
    4 Oct 2012
    Messages:
    8,560
    Thanks Received:
    2,481
    Location:
    East Renfrewshire
    Country:
    United Kingdom
    If the boiler isn't firing up when you open the hot water tap, then the boiler isn't seeing the demand, or there isn't enough demand to trigger the differential switch.

    There are a few reason that could cause this, it could be the valves but it really should be unless your mains water pressure/flow is poor. The 105e's are known for issues around the venturi/diverter/differential valve as suggested, when they get older they can become less sensitive - for lack of a better way to describe it - and sometimes need more flow to push the pin out far enough to trigger the switch.

    If it is the pressure switch/diverter in the boiler then the valve may need serviced. Easy to check, get someone to turn on the hot water and check to see how far the front pin extends, sometimes they extend but not enough to activate the microswitch. These valves are very serviceable, lots of parts kits & vids available showing how.
     
  17. leevis

    leevis

    Joined:
    2 May 2007
    Messages:
    566
    Thanks Received:
    4
    Country:
    United Kingdom
    Just out of interest on the Venturi side of things, this was definitely broken before and the symptom was the shower not getting any hot water. Currently the shower is still getting hot water, would this mean the the venturi is OK?
     
Loading...

Share This Page