Worcester Bosch 28CDi RSF Combi problem

Discussion in 'UK DIY' started by richard_hamer2000@yahoo.co.uk, Feb 18, 2004.

  1. Guest

    Hello,
    A couple of weeks ago I got suspicious that a small amount of water
    may have leaked from the bottom of the boiler onto the surface below.
    I put a "collector" thre to get an idea of the amount. I checked it a
    few days ago and there just seemed to be a small patch ((worrying in
    itself).

    Today, I had trouble with the how water demand - turning a tap fully
    on would activate the hot water from the boiler, but lower flows, eg
    my morning shower, would not get it to heat up.

    Since then, I have noticed that larger amounts of clear water have
    leaked from the boiler into the tray, eg perhaps enough to fill a mug
    by 1 cm every half hour.

    Does anyone have any experience of this or ideas on what might be
    wrong?

    Also, I have tried contacting Bosch as I seem to recall they used to
    offer servicing and repairs directly, but I am having trouble finding
    contact details.

    Do Bosch still offer direct repairs and servicing, or are there any
    other reliable specialist firms who I could contact, rather than
    plucking an outfit at random from the yellow pages? My location is
    West London.

    Thanks,
    Richard Hamer
     
    , Feb 18, 2004
    #1
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  2. Martin Guest

    <> wrote in message
    news:...
    > Hello,
    > A couple of weeks ago I got suspicious that a small amount of water
    > may have leaked from the bottom of the boiler onto the surface below.
    > I put a "collector" thre to get an idea of the amount. I checked it a
    > few days ago and there just seemed to be a small patch ((worrying in
    > itself).
    >
    > Today, I had trouble with the how water demand - turning a tap fully
    > on would activate the hot water from the boiler, but lower flows, eg
    > my morning shower, would not get it to heat up.
    >
    > Since then, I have noticed that larger amounts of clear water have
    > leaked from the boiler into the tray, eg perhaps enough to fill a mug
    > by 1 cm every half hour.
    >
    > Does anyone have any experience of this or ideas on what might be
    > wrong?
    >
    > Also, I have tried contacting Bosch as I seem to recall they used to
    > offer servicing and repairs directly, but I am having trouble finding
    > contact details.
    >
    > Do Bosch still offer direct repairs and servicing, or are there any
    > other reliable specialist firms who I could contact, rather than
    > plucking an outfit at random from the yellow pages? My location is
    > West London.
    >
    > Thanks,
    > Richard Hamer


    Their web site is http://www.worcester-bosch.co.uk/
    You can contact them for service/repair or with a technical query via the
    web site, I found them very responsive and helpful.
     
    Martin, Feb 18, 2004
    #2
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  3. In article <>,
    writes
    >Hello,
    >A couple of weeks ago I got suspicious that a small amount of water
    >may have leaked from the bottom of the boiler onto the surface below.
    >I put a "collector" thre to get an idea of the amount. I checked it a
    >few days ago and there just seemed to be a small patch ((worrying in
    >itself).
    >
    >Today, I had trouble with the how water demand - turning a tap fully
    >on would activate the hot water from the boiler, but lower flows, eg
    >my morning shower, would not get it to heat up.
    >
    >Since then, I have noticed that larger amounts of clear water have
    >leaked from the boiler into the tray, eg perhaps enough to fill a mug
    >by 1 cm every half hour.
    >
    >Does anyone have any experience of this or ideas on what might be
    >wrong?
    >
    >Also, I have tried contacting Bosch as I seem to recall they used to
    >offer servicing and repairs directly, but I am having trouble finding
    >contact details.
    >
    >Do Bosch still offer direct repairs and servicing, or are there any
    >other reliable specialist firms who I could contact, rather than
    >plucking an outfit at random from the yellow pages? My location is
    >West London.
    >
    >Thanks,
    >Richard Hamer



    How strange! My Worcester 28Cdi RSF had similar problems a few weeks
    back too...

    I had excessive changes in pressure, lack of hot water and water
    appearing from the pressure relief valve.

    Check Ed Siretts FAQ - it will answer everything!

    Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

    What's the system pressure doing? If it's peaking at 3 bar then the
    relief valve is opening - hence the water leaking? If so your pressure
    vessel may be ruptured. Check the air valve on it. If water comes out,
    you'll need a new vessel. The easy way to replace it is to take the
    boiler off the wall, drill out the rivets that hold the mounting plate
    and drop it out of the back.

    Lack of hot ware could be the diverter valve. Take the flow switches
    off, by removing the C clip and take a look at the plunger pin. It
    should come out when the hot tap goes on. If not, you need a new valve.

    We used an Ariston (i think) diaphragm instead of buying a whole new
    valve.

    The install manual is available on the net, it has a fault finding chart
    which may help.

    God, I didn't even know what a combi boiler was last month.....!

    TTFN

    --
    Richard Markham
     
    Richard Markham, Feb 20, 2004
    #3
  4. Worester Bosch were very good. responded to my email within half an
    hour (I was most surprised - I usually despair when I have to rely on
    organisations replying to emails, particularly urgent ones ...).

    I managed to book a next day "tiered price" appointment - ie one price
    if it just needs service, another if it needs any parts, and a third
    price if the heat exchanger needs replacing. Not unreasonable,
    particularly when it's being serviced by trained Bosch people, and
    nice to know the cost is capped.

    He sorted out a long standing problem which I posted about a few years
    back - when the central heating temperature dial is close to the
    actual temperature, for low settings, the boiler repeatedly fires up
    then shuts down instantly, over and over again. For the benefit of
    anyone else who has this problem, he replaced the main controller
    board.

    He also replaced the heat exchanger plate, which was the source of the
    leak.

    However, in terms of hot water not firing up, he said the boiler
    seemed fine and that he thought the problem was cross-flow in a mixer
    valve, presumably high pressure cold water leaking through a mixer
    into the hot water inlet.

    Now, I know that my shower does have this problem, but am not sure why
    the boiler is suddenyl unable to cope with it after five years.
    Alternatively, it could be a new mixer fault elsewhere.

    Does anyone have any ideas on how to easily diagnose the source of
    such a mixer problem - I have four sets of mixers - without physically
    disconnecting each pair of taps in turn and trying the hot water until
    it works?

    Would I be right in thinking that the more modern taps, such as a
    4-year-old kitchen tap, which have physically separate outlets for the
    hot and cold streams in the tap head, cannot be the source of such
    problems?

    Hope all this helps someone in the future ...
    Thanks,
    Richard
     
    Richard Hamer, Feb 20, 2004
    #4
  5. Having isolated put a stop end in the hot water pipe out of the
    boiler, so that only a single (washing machine) outlet is in the run,
    the hot water problem remains.

    The tap needs to be turned fully on to get the boiler to fire up. This
    is a much greater flow than used to be necessary for hot water, and
    the kitchen sink and shower are unable to trigger it.

    I am therefore sure the problem is within the boiler itself. All other
    problems have been fixed. Bosch will be back in a week to take another
    look, but in the meantime does anyone have any ideas on where the
    problem might lie, eg the hot water diverter valve / flow switch
    sensor thingy?

    Thanks,
    Richard
     
    Richard Hamer, Feb 21, 2004
    #5
  6. Ed Sirett Guest

    On Sat, 21 Feb 2004 05:06:15 +0000, Richard Hamer wrote:

    > Having isolated put a stop end in the hot water pipe out of the
    > boiler, so that only a single (washing machine) outlet is in the run,
    > the hot water problem remains.
    >
    > The tap needs to be turned fully on to get the boiler to fire up. This
    > is a much greater flow than used to be necessary for hot water, and
    > the kitchen sink and shower are unable to trigger it.
    >
    > I am therefore sure the problem is within the boiler itself. All other
    > problems have been fixed. Bosch will be back in a week to take another
    > look, but in the meantime does anyone have any ideas on where the
    > problem might lie, eg the hot water diverter valve / flow switch
    > sensor thingy?


    The web site is down ATM so I can't check the precise means by which the
    boiler senses water flow. However the symptom of insensitivity to HW flow
    is very likely to indicate a split diaphragm of some sort.
    This part will likely not exceed £40 (whole valve) or £10 a replacement
    diaphragm.

    --
    Ed Sirett - Property maintainer and registered gas fitter.
    The FAQ for uk.diy is at www.diyfaq.org.uk
    Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
    Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
     
    Ed Sirett, Feb 21, 2004
    #6
  7. In article <>, Ed
    Sirett <> writes
    >On Sat, 21 Feb 2004 05:06:15 +0000, Richard Hamer wrote:
    >
    >> Having isolated put a stop end in the hot water pipe out of the
    >> boiler, so that only a single (washing machine) outlet is in the run,
    >> the hot water problem remains.
    >>
    >> The tap needs to be turned fully on to get the boiler to fire up. This
    >> is a much greater flow than used to be necessary for hot water, and
    >> the kitchen sink and shower are unable to trigger it.
    >>
    >> I am therefore sure the problem is within the boiler itself. All other
    >> problems have been fixed. Bosch will be back in a week to take another
    >> look, but in the meantime does anyone have any ideas on where the
    >> problem might lie, eg the hot water diverter valve / flow switch
    >> sensor thingy?

    >
    >The web site is down ATM so I can't check the precise means by which the
    >boiler senses water flow. However the symptom of insensitivity to HW flow
    >is very likely to indicate a split diaphragm of some sort.
    >This part will likely not exceed £40 (whole valve) or £10 a replacement
    >diaphragm.
    >


    Valves are £75 plus vat and you can't get the diaphragm as a spare part!



    --
    Richard Markham
     
    Richard Markham, Feb 21, 2004
    #7
  8. John Guest

    "Richard Markham" <> wrote in message
    news:$...
    > In article <>, Ed
    > Sirett <> writes
    > >On Sat, 21 Feb 2004 05:06:15 +0000, Richard Hamer wrote:
    > >
    > >> Having isolated put a stop end in the hot water pipe out of the
    > >> boiler, so that only a single (washing machine) outlet is in the run,
    > >> the hot water problem remains.
    > >>
    > >> The tap needs to be turned fully on to get the boiler to fire up. This
    > >> is a much greater flow than used to be necessary for hot water, and
    > >> the kitchen sink and shower are unable to trigger it.
    > >>
    > >> I am therefore sure the problem is within the boiler itself. All other
    > >> problems have been fixed. Bosch will be back in a week to take another
    > >> look, but in the meantime does anyone have any ideas on where the
    > >> problem might lie, eg the hot water diverter valve / flow switch
    > >> sensor thingy?

    > >
    > >The web site is down ATM so I can't check the precise means by which the
    > >boiler senses water flow. However the symptom of insensitivity to HW

    flow
    > >is very likely to indicate a split diaphragm of some sort.
    > >This part will likely not exceed £40 (whole valve) or £10 a replacement
    > >diaphragm.
    > >

    >
    > Valves are £75 plus vat and you can't get the diaphragm as a spare part!


    Take a look at the B E S Website and see if your valve is among those they
    sell. Most of the Worcester valves are made by Giannoni which is what BES
    sell
     
    John, Feb 26, 2004
    #8
  9. Kefalonia

    Joined:
    Feb 6, 2010
    Messages:
    1
    Box of Diaphragm Kits to fit Giannoni divertor valves-
    £43.70 inc. VAT

    Website: ezypart

    Freefone: 0800 58 77 482 Fax: 0870 240 1853

    To fit, simply undo the screws on the valve and replace with the new diaphragm and spindle.

    These diaphragm kits are the genuine replacement parts for the Giannoni diverter valves and can be used to replace and repair faulty diaphragms in diverter valves in Ariston, Alpha Ocean, Baxi Potterton, Caradon, Glow Worm, Halstead, Ideal, Ravenheat, Servowarm, Stelrad, Sime and Worcester Bosch combination boilers.

    The diaphragm assembly includes a flexible convoluted black ethylene propylene diaphragm that is clamped between the two parts of the diverter valve diaphragm chamber. The diaphragm is clenched between two stainless steel discs and mounted on a stainless steel shaft or spindle. A special notched plate, held onto the shaft by a circlip, accurately determines the domestic water flow rate at which the diverter valve will operate. A number of helical springs are also mounted on the shaft, designed to balance the movement of the diaphragm and to return the valve to its normal position when the domestic hot water demand ceases.

    Hope this helps!
     
    Kefalonia, Feb 6, 2010
    #9
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