Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Pressurised domestic water system problem

Options
  • 06-04-2008 12:13pm
    #1
    walhunt
    Closed Accounts Posts: 4 ✭


    Can anyone advise on a problem with pressurised domestic water system? The system supplies the showers and taps in the house and it ran perfectly after it was installed. After 12 months the water temperature in the taps and showers fluctuates, so when having a shower the water goes from being too hot to too cold. When a tap is run on just hot the pressure remains constant, when run on cold the pressure fluctuates. The pressures have been reset on the on the pump and the main vessel, all the non return valves have been checked and are working.

    Any thoughts.


Comments

  • Options
    #2
    ircoha
    Closed Accounts Posts: 2,290 ✭✭✭ircoha


    walhunt wrote: »
    Can anyone advise on a problem with pressurised domestic water system? The system supplies the showers and taps in the house and it ran perfectly after it was installed. After 12 months the water temperature in the taps and showers fluctuates, so when having a shower the water goes from being too hot to too cold. When a tap is run on just hot the pressure remains constant, when run on cold the pressure fluctuates. The pressures have been reset on the on the pump and the main vessel, all the non return valves have been checked and are working.

    Any thoughts.

    When u say all the non-return valves, how many are there?

    In most normal set ups there is only one between the outlet from the pump and where this pipe splits to enter the HW cylinder and go on as cold supply.
    Quessing here now:)
    Have you mixer taps? perhaps there is some scaling on the inners of the taps causing them to stick.

    Have you checked to see there is no blockage between the cold water feed tank and the inlet pipe to pump


  • Options
    #3
    walhunt
    Closed Accounts Posts: 4 ✭walhunt


    There is one after the pump as you described and the one on the inlet to the pump which comes as part of the pump kit (usually for sypplys from a well).

    Yes I have mixer taps and all that I found was some flux caught in the gauze, which was cleared.

    I have also let the pipe from the feed tank run into a bucket which is a 1Ins supply and ther is more than enough water and no debris in the bucket afterwards.

    The cycle time from the change from too hot to too cold is about 20 seconds and is in all the taps.

    The problem occurs when the pump cuts out for a few second and the cold pressure drops. All I can suggest is that the pressure vessel is not working properly or is too small (18Ltr Pressure Vessel and 300Ltr Hot Water Tank).


  • Options
    #4
    ircoha
    Closed Accounts Posts: 2,290 ✭✭✭ircoha


    just reading ur response and it seems u have hit on the problem: it would seem that what ever sort of sensor is on the pump to tell it turn off is acting up as the PV is passive and it all worked before.
    What make is the pump?


  • Options
    #5
    walhunt
    Closed Accounts Posts: 4 ✭walhunt


    Its a Grundfos MQ 3-35


  • Options
    #6
    ircoha
    Closed Accounts Posts: 2,290 ✭✭✭ircoha


    walhunt wrote: »
    Its a Grundfos MQ 3-35


    I trust u have seen this:
    http://net.grundfos.com/doc/webnet/mq/frames_html.htm

    perhaps an email to them may help, explaining the problem: they are in Denmark so you should get a response or maybe even a cartoon:)


  • Advertisement
Advertisement