Baxi Combi Boiler - Hot Water But No Central Heating

Discussion in 'Plumbing and Central Heating' started by EMT999, 25 Mar 2013.

  1. EMT999

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    Hello

    I have a 'Baxi Duo-tec Combi 28 HE A' condensing combination boiler.

    It is just over 1 year old and was already installed into our new-build property by the developers prior to us moving in.

    It has been working fine up until today, when I noticed that the radiators were stone cold. They have all been bled recently, and have been working fine yesterday, getting very hot within minutes of turning on the heating.

    The hot water still comes through the tap on demand and you can hear the boiler fire up when the tap is turned on.

    The wireless thermostat is also working fine, and I have set the heating to its maximum temperature, which displays a flame symbol on the thermostat and you can then hire the boiler fire up and the green light come on to indicate the central heating is in operation. The boiler is warm to the touch and you can hear it doing its thing.

    The radiators are still stone cold. No error messages are displayed, it still makes all its normal noises, radiators have been re-bled, radiator thermostats have all been set to maximum, boiler has been reset multiple times, as has the wireless thermostat, but no still hot water going to the radiators.

    Fortunately we're approaching April so heating is hopefully going to be less of an issue provided the hot water still works, but I would love to know what is causing this fault. Pump problem of some sort perhaps? Despite the boiler being a year old?

    Any ideas?

    Thanks in advance for your help.
     
  2. gas112

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    sure no one has touched the isolating valves under the boiler and turned one off by mistake,
     
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  3. EMT999

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    Very sure!
     
  4. MANDATE

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    My understanding is that there are two circuits the water can take and the movement of a diverter valve dictates which one is in operation.
    The pump is used for both circuits.
    The diverter valve also triggers one of two micro switches (HW or CH) depending on the valves position.
    I'd be looking at:
    (a) The wire less stat could be faulty.
    To fit a room stat normally involves removing a wire 'link' so replacing the 'link' temporarily would help
    (b) Diverter valve may be stuck. Should I would think be able to prove if it goes to CH position and trigger the CH micro switch
    (c) CH micro switch may not be triggered fully to make contact or contacts get burned /dirty so contact not made. Continuity of switch could be checked.
    These are just my ideas based on a different combi
     
  5. Baxmax

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