Fridge not working on electricity

Kerry Watkins
Kerry Watkins Forum Participant Posts: 325
100 Comments
edited December 2015 in Caravans #1

We gave a Hobby caravan and about three months ago we replaced the electric 240 element as it had failed. Now find that the fridge is not working on electricity again. When we turn the thermostat dial we find
that the normal 'clicking' sound is absent. Was wondering whether it may ge a defective element again or perhaps the thermocouple or if the knob itself is defective. The fridge works fine off gas and 12 Volt.

I would appreciate any advice.

Thanks

Kerry

Comments

  • rogher
    rogher Forum Participant Posts: 609
    500 Comments
    edited December 2015 #2

    When working on electric, the fridge will not 'click'. The clicking noise is the sound of the gas ignitor, which will only occur when on gas.

  • omendri
    omendri Forum Participant Posts: 75
    edited December 2015 #3

    Kerry

    You do not state the make of 'fridge but I am guessing Thetford as I replaced four 240 volt heater elements in under four years on a Thetford 175 double door refrigerator. To be fair to Thetford each was replaced at nil charge,  the last one on my home drive
    by a Thetford engineer.  No reason could be found for the multiple faulting but I am guessing a "bad"  batch of  elements because the "final" one (fitted by Thetford) outlived our ownership. 

    Ome "n" Dri

  • Boff
    Boff Forum Participant Posts: 1,742
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    edited December 2015 #4

    if you can get to the element wires if the element is working them it should give a resistance of approximately 500 ohms if I remember correctly.  If it gives a value of zero or several million ohms then the element it broken.  Of course don't neglect the
    obvious and check for a loose connection.  If the element tests out ok then I guess the thermostat is the likely culprit.

  • rogher
    rogher Forum Participant Posts: 609
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    edited December 2015 #5

    But isn't the same element used for 12V operation, which Kerry believes is fine?

  • Kerry Watkins
    Kerry Watkins Forum Participant Posts: 325
    100 Comments
    edited December 2015 #6

    Omendry

    sorry, the fridge is a Dometic RMH 7390L

    the element was tested when it was put in but could have failed in the mean time.

  • Boff
    Boff Forum Participant Posts: 1,742
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    edited December 2015 #7

    Mains and 12 v are seperate elements Afaik. So they can fail independently 

  • EmilysDad
    EmilysDad Forum Participant Posts: 8,973
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    edited December 2015 #8

    But isn't the same element used for 12V operation, which Kerry believes is fine?

    There's a 12v DC heater & a 240v AC heater ....... two seperate heaters ...... a 12v heater wouldn't last long with mains voltage applied
    Wink

  • rogher
    rogher Forum Participant Posts: 609
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    edited December 2015 #9

    True, but 12V across a 240V element would last forever! (I had assumed that it was one of the reasons why 12V operation is so poor.)

  • Rayrowe35
    Rayrowe35 Forum Participant Posts: 112
    edited December 2015 #10

    On my Dometic refrigerator there are definitely two elements. 12 volt operation is not much poorer than 240 volts. It depends on the size of the heater. I had to replace a failed mains element. To do the tests described by Boff, you need to access the control
    box terminals. This will probably involve removing the refrigerator, which includes disconnecting the gas supply. The pipe for this in my case is situated between the top of the fridge and the work surface. Space is very limited and the operation is difficult.
    Refitting is even worse. Please be sure that you have the tools and skills to complete this work before starting.

  • Boff
    Boff Forum Participant Posts: 1,742
    1000 Comments
    edited December 2015 #11

    True, but 12V across a 240V element would last forever! (I had assumed that it was one of the reasons why 12V operation is so poor.)

    if you look a the wattages of 12v and 230v elements  generally there is no significant differences. I think that the problem is getting  12v to the 12v element the problems lie with the car and caravan wiring and you end up with much less than 12 v at the element  or the smart relay doesn't trigger very often to  you get no power at all ( got that T shirt)

  • cyberyacht
    cyberyacht Forum Participant Posts: 10,218 ✭✭✭
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    edited December 2015 #12

    Is your van level? That can stop it working.

  • Kerry Watkins
    Kerry Watkins Forum Participant Posts: 325
    100 Comments
    edited December 2015 #13

    Thanks for the advice everyone, the site is brilliant for matters such a this! The van is level Cyberyacht. The fridge will need to come out and the gas pole removed. I will t to and take th fridge out and check the element to see if it is working. If not
    then It will need to be replaced. I will keep you informed.

  • HarleyDave
    HarleyDave Forum Participant Posts: 150
    edited December 2015 #14

    Is your van level? That can stop it working.

    Write your comments here...Had same problem on me campervan,parked on camber caused it,but I see yours is level

  • Kerry Watkins
    Kerry Watkins Forum Participant Posts: 325
    100 Comments
    edited December 2015 #15

    Thanks everyone for your help. It was the element after all.

    kerry

  • omendri
    omendri Forum Participant Posts: 75
    edited December 2015 #16

    Thanks everyone for your help. It was the element after all.

    kerry

    Glad to hear that you have identified the fault. It was suggested to me during the period of multiple Thetford 240v heater failures that reducing the thermostat setting to the recommended (3) would aid longevity. No idea if technically this has merit but
    the last heater fitted was still working well after 12 months(this was a record for my Thetford 175 fridge freezer)  with a maximum "stat" setting of no more than 3. 

     

    Ome "n" Dri

  • Woody19
    Woody19 Forum Participant Posts: 43
    edited January 2016 #17

    Just two points: running the fridge on 12V from the car whilst towing is only designed to keep an already cold fridge cold - it will not cool a fridge that has not already been on mains or gas to get it cold.

    Secondly the thermostat on the front of the fridge only works on mains but it <does> (usually) click if the knob is rotated - the click is often felt rather than heard. There is no thermostatic control on gas operation.

    Both the 12V and mains elements draw about 120W so 10A when towing but only 0.5A on mains. It is therefore important that the 12V wiring in the towing vehicle is heavy enough to handle the 10A current without significant voltage drop.

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