Central Heating pump knocking?

Discussion in 'UK Home Improvement' started by milleniumaire@hotmail.co.uk, Nov 7, 2006.

  1. Guest

    A couple of weeks ago I refitted a radiator in our bathroom after it
    had been tiled. Coincidentally, during the back end of last week I
    noticed a knocking sound at the same time as I could hear water being
    pumped through the radiators in the house. I wasn't concerned as I
    thought maybe some air had got into the system (it is a sealed system
    with a 8 year old Saunier Duval Thelia Twin combi boiler) and I would
    go around the house and bleed all the radiators. Last night, the
    knocking became continuous and even louder and I now realise it isn't
    coming from the pipework or the radiators it is coming from the boiler
    but is being amplified through the piping so that it can be heard
    throughout the house. The noise appears to be coming from what I think
    is the pump which seems to be an integral part of the boiler.

    The noise is a regular loud knocking sound and stops when I switch of
    the boiler, but starts when either the hot water only or heating and
    hot water settings are selected. The radiators are still warming up
    and the water is still hot so everything appears to be working okay
    apart from the loud noise which is so disruptive that we had to turn
    the boiler off last night in order for us and our children to get any
    sleep.

    Our heating system is insured but an engineer won't be out to look at
    it until Thursday, and then I suspect we will have to wait another week
    while they get whatever spare part is required.

    If this is a mechanical problem with the pump is it likely to be
    dangerous to leave it on?
    Is the problem likely to be the bearings in the pump or is it possible
    that trapped air could cause this noise? I ask this as if it is a
    problem with the pump I'm surprised that the radiators all around the
    house are still hot i.e. the pump is still working.

    I would appreciate any suggestions on what the problem might be and
    anything I could do to fix it or minimise the noise before the engineer
    arrives later this week.

    Thanks.
     
    , Nov 7, 2006
    #1
    1. Advertising

  2. Codswallop Guest

    <> wrote:
    >A couple of weeks ago I refitted a radiator in our bathroom after it
    > had been tiled. Coincidentally, during the back end of last week I
    > noticed a knocking sound at the same time as I could hear water being
    > pumped through the radiators in the house. I wasn't concerned as I
    > thought maybe some air had got into the system (it is a sealed system
    > with a 8 year old Saunier Duval Thelia Twin combi boiler) and I would
    > go around the house and bleed all the radiators. Last night, the
    > knocking became continuous and even louder and I now realise it isn't
    > coming from the pipework or the radiators it is coming from the boiler
    > but is being amplified through the piping so that it can be heard
    > throughout the house. The noise appears to be coming from what I think
    > is the pump which seems to be an integral part of the boiler.
    >
    > The noise is a regular loud knocking sound and stops when I switch of
    > the boiler, but starts when either the hot water only or heating and
    > hot water settings are selected. The radiators are still warming up
    > and the water is still hot so everything appears to be working okay
    > apart from the loud noise which is so disruptive that we had to turn
    > the boiler off last night in order for us and our children to get any
    > sleep.
    >
    > Our heating system is insured but an engineer won't be out to look at
    > it until Thursday, and then I suspect we will have to wait another week
    > while they get whatever spare part is required.
    >
    > If this is a mechanical problem with the pump is it likely to be
    > dangerous to leave it on?
    > Is the problem likely to be the bearings in the pump or is it possible
    > that trapped air could cause this noise? I ask this as if it is a
    > problem with the pump I'm surprised that the radiators all around the
    > house are still hot i.e. the pump is still working.
    >
    > I would appreciate any suggestions on what the problem might be and
    > anything I could do to fix it or minimise the noise before the engineer
    > arrives later this week.
    >
    > Thanks.


    If you put the tip of a screwdriver on the pump casing and put your ear
    against the screwdriver handle, that should confirm that the noise is coming
    from the pump. It could be worn bearings and isn't dangerous. If it is
    possible to change the speed of the pump you could try running it at a
    slower of faster setting. I doubt that air would cause loud knocking. An old
    blanket wrapped around the pump might muffle the sound if it is safe to do
    that.
     
    Codswallop, Nov 7, 2006
    #2
    1. Advertising

  3. Merryterry Guest

    wrote:


    > I would appreciate any suggestions on what the problem might be and
    > anything I could do to fix it or minimise the noise before the engineer
    > arrives later this week.
    >
    > Thanks.


    Could be water too hot and creating steam in the pump. Have you turned
    the boiler Temp up lately? Have had this problem on my oversized boiler.
     
    Merryterry, Nov 7, 2006
    #3
  4. Guest

    As far as I'am aware the temperature hasn't been turned up. I have
    also tried turning down the hot water and heating temperatures but this
    makes no difference.

    When I arrived home tonight (to the constant, regular, loud knocking
    noise coming from the boiler in the garage) I noticed that all the
    downstairs radiators and pipes were cold and I immediately assumed that
    the heating was no longer working. However, upstairs all radiators
    were hot! How can this be?

    Is it possible that the knocking is being caused by a "switch" that is
    allowing hot water to the upstairs radiators, but not downstairs?

    I'm even more confused now.

    Paul.
     
    , Nov 7, 2006
    #4
  5. malc Guest

    wrote:
    > As far as I'am aware the temperature hasn't been turned up. I have
    > also tried turning down the hot water and heating temperatures but
    > this makes no difference.
    >
    > When I arrived home tonight (to the constant, regular, loud knocking
    > noise coming from the boiler in the garage) I noticed that all the
    > downstairs radiators and pipes were cold and I immediately assumed
    > that the heating was no longer working. However, upstairs all
    > radiators were hot! How can this be?
    >
    > Is it possible that the knocking is being caused by a "switch" that is
    > allowing hot water to the upstairs radiators, but not downstairs?
    >
    > I'm even more confused now.
    >

    More likely it is your pump that's knackered. The reason your upstairs rads
    are heating is due to thermal syphoning.

    --
    Malc

    "AFB Mr Tracey."
    "Underbirths are og"

    Les Barker - Irrational Neutscene
     
    malc, Nov 7, 2006
    #5
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. john

    Central Heating Pump

    john, Jul 4, 2003, in forum: UK DIY
    Replies:
    3
    Views:
    828
  2. kipper

    Central Heating Pump

    kipper, Nov 10, 2003, in forum: UK DIY
    Replies:
    1
    Views:
    281
    BigWallop
    Nov 10, 2003
  3. Simon Elliott

    Knocking sound in central heating system

    Simon Elliott, Nov 23, 2005, in forum: UK DIY
    Replies:
    8
    Views:
    1,027
    Dave Plowman (News)
    Dec 1, 2005
  4. Manf. Engnr.
    Replies:
    0
    Views:
    496
    Manf. Engnr.
    May 6, 2004
  5. David

    Central heating making a knocking noise

    David, Nov 10, 2003, in forum: UK Home Improvement
    Replies:
    1
    Views:
    1,352
    BigWallop
    Nov 11, 2003
Loading...

Share This Page