Dometic Fridge - Possible 12v Problem?

Discussion in 'Fridges & Ovens' started by magicsurfbus, Jul 7, 2015.

  1. magicsurfbus

    magicsurfbus Funster

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    I'm beginning to suspect something's wrong with the 12v circuit in our Dometic fridge, which is about 10 years old.

    The green front panel light goes on for 12v, so power's getting to it, but the LCD temperature sensor I've fitted shows it getting slowly warmer when we're driving. The thermostat is usually set to the middle setting or slightly cooler.

    No problem on 230v or gas that I can see, just on 12v.

    Am I right in thinking the 12v and 230v elements are separate components? Also wondering about if there's a loose or corroded connection.

    If the leisure battery was packing up could this prevent power going to the fridge in 12v mode? The battery seems OK but it is getting on a bit.

    Any pointers gratefully received here.
     
  2. pappajohn

    pappajohn Funster Life Member

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    12v and 230v are seperate heating coils.
    the leisure battery has no relation to the 12v system which SHOULD only work when driving.

    It certainly sounds like the 12v heating coil has failed.
     
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  3. funflair

    funflair Funster Life Member

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    It's not right to say that the 12v leisure has no relevance to the fridge 12volt operation as some vans are wired to run off the leisure batteries when the engine is running.

    First step would be to find out which source it runs from.

    Martin
     
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  4. DavidG58

    DavidG58 Funster

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    when you say it gets warmer, how much does it actually change by, the 12V operation on a fridge is really inefficient, at best it would maintain temperature, if it is only going up by a couple of degrees that could still be the best you would get :)
     
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  5. scotjimland

    scotjimland Funster Life Member

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    Not sure which fridge you have.. but some have two 12v supplies.. one for the electronic board.. the other for the 12v element which is only live when engine running. So the green light may only indicate that the control voltage is present.

    At the back of the fridge.. check while the engine is running that you are actually getting 12v supply for the element.

    If no supply it could be the split charge relay which has two sets of contacts.. one for charging the leisure battery, the other is the fridge supply.. or the in-line fuse from the alternator to the relay is blown.

    If fuse ok but no supply.. the relay is u/s.

    If you have a supply at the fridge, then it's either corroded or bad connection at the element or the element is open or short circuit. Can check with multimeter.
     
    Last edited: Jul 8, 2015
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  6. tonyidle

    tonyidle Funster

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    With the correct size wiring the frig is capable of freezing everything inside it on 12v. And will do so on a long drive. There is no thermostat control on 12v and the element is the same wattage as the mains element. Their reputation for being marginal on 12v is entirely due to the inadequate wiring installed by the converter.
     
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  7. tonyidle

    tonyidle Funster

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    12v (or mains) elements are pretty cheap and are very easy to install.
     
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  8. scotjimland

    scotjimland Funster Life Member

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    easy to change.. yes..

    cheap ? well , that's what I thought until I checked the prices.. about £30 - £50 ..depending on model ..
     
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  9. tonyidle

    tonyidle Funster

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    The last one I bought was around £20. It was a while ago though :D.
     
  10. magicsurfbus

    magicsurfbus Funster

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    There's definitely a current arriving at the back of the fridge when the engine's running, just over 13v - I've checked with a multimeter. The cabling looks reasonably substantial too.

    I'm gambling on it being the element so I've ordered a spare one online (not eBay, too expensive) for £42 - if it turns out to be something else at least I've got a spare element for another time.

    Advice and info appreciated as always - thank you.
     
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