One Hob on the gas cooker wont stay alight

Discussion in 'Fridges & Ovens' started by N&K, Oct 5, 2008.

  1. N&K

    N&K

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    Hi

    We have a 3 ring gas hob in our motorhome. 2 of them work fine, the 3rd lights ok, but after releasing the knob it goes out. Even if you hold the knob in for a minute or so it goes out. Eventually it will stay alight after many minutes of holding the hob knob. If there something to check / change to fix this?

    Thanks

    N&K
     
  2. Diabalo

    Diabalo Funster

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    Sound like you need a new thermo coupler:thumb:
     
  3. N&K

    N&K

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    Last edited: Oct 5, 2008
  4. Braunston

    Braunston Read Only Funster

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    Hi,

    If you can get it to stay on after holding the knob for an extended period, its very likely that the flame is not playing on the thermocouple tip correctly, Its worth looking to see if the tip is positioned exactly the same on the other burners and that the flame is playing on the tip in exactly the same manner, as you may be able to move it slightly or clean it and the burner cap as it could just be that the flame that should be directed towards the thermocouple tip is slightly blocked or to long/short remember the centre of the flame is cold albeit everything that surrounds it is very hot and the thermocouple needs the heat of the flame to work,

    Not withstanding all the above you could try a new thermocouple and if that fails then its the Flame Failure Device that is probably faulty but unless you are confident in working with gas be careful as the reason for the thermocouple etc is for your safety and you really don't want to compromise that,

    I would therefore suggest that you get your local CORGI engineer to look at it for you.

    Hope that helps,
     
    Last edited: Oct 5, 2008
  5. N&K

    N&K

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    Thanks Braunston, I'll give it a close inspection and try your suggestions, thanks :thumb:
     
  6. Beachbum

    Beachbum Read Only Funster

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    Light the burner, hold it in for a few seconds then release and push in real fast a couple of times then slowly release. Follow this procedure whenever you lightup for use. After a couple of times, you will be able to light the burner and release gently. It happened to me and the gas fitter in Germany showed me. It works perfect now.
     
  7. Diabalo

    Diabalo Funster

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    Yes that is a thermocoupler, what ever is inside heats up expands and holds the gas valve open, if the flame goes out it shuts the gas off.
     
  8. Braunston

    Braunston Read Only Funster

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    Hi

    Just for clarification the thermocouples used as part of the safety devices on gas appliances work on the principal of when heat is applied to the tip of the thermocouple it generates a very small current (50 mill-amp I believe) that is sufficient to energize an electromagnet which in turn holds a gas valve open while the current flows.

    The electromagnet is not strong enough to pull the valve open by itself, that is why as part of the action to turn the appliance on you need to hold/push the button/knob in, which is doing 2 things one allowing the gas to flow to the burner/pilot etc and the second is holding/pushing the valve against the electromagnet until sufficient electrical energy has energized the magnet sufficiently to hold the valve on its own ?

    Remove the source of the heat (Pilot -Burner -etc goes out) and the electro magnet loses its energy and the valve drops shutting off the gas,

    sorry its a bit long winded but I hope it makes sense, it is a good form of flame failure protection and should not be interfered with by untrained people, as with any gas appliances you should call in a CORGI registered engineer to affect any repairs.


     
    Last edited: Oct 6, 2008
  9. N&K

    N&K

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    Fixed

    Beachbum - that worked perfectly - Thanks muchly :BigGrin::thumb:
     
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