Fridge gas not igniting

HamishT
HamishT Forum Participant Posts: 10
edited March 2021 in Caravans #1

Hello and thanks for looking at my query.  I have a problem with my fitted fridge (Thetford N97, ten years old, hardly used on gas) running on gas.  Here we go…

The fridge has three way automatic power running on propane.  The other gas appliances in the caravan are fine.  The fridge works fine on 240V and 12V. I have removed the grille on the outside to see the gas problem which is that…

·        The fridge gas comes through to the burner OK and is ignited by the piezo automatically

·        The piezo continues to run when the gas is ignited

·        The gas then burns for about five seconds at which point the piezo stops igniting

·        The gas then extinguishes

·        I retry several times and get the same problem

I have tried running the fridge on 240V for a couple of days beforehand to see if that makes any difference, but it doesn’t do the trick.

Doing a bit of surfing I see that the problem may be one or both of…

·        A new burner assembly (not very expensive)

·        A new PCB (expensive!)

***Do any members have an idea which of these it might be or how to diagnose that?

***Does anybody have any tips on how to extract the fridge so the work can be done more easily?

Thank you for looking at this and any tips would be greatly appreciated – especially if we can escape somewhere next month!!

Comments

  • JVB66
    JVB66 Forum Participant Posts: 22,892
    1000 Comments
    edited March 2021 #2

    It may be the that the thermo couple? is not working which which is a safrty device that will close off the gas if it fails 

  • triky auto
    triky auto Forum Participant Posts: 8,690
    1000 Comments
    edited March 2021 #3

    If your exhaust outlet to the fridge ,has a cover over it ,,,you MUST remove that before trying to use gas on the fridge .Even then ,it MAY take a few seconds to bleed through before ignighting .

  • Belair
    Belair Forum Participant Posts: 2
    edited March 2021 #4

    We have the same problem on our Coachman 3way fridge. It does not light on gas.We were advised by mobile engineer on the last service that it was the PCB. 
    I am hoping to get it looked at on the next service.

    we don’t use it on gas normally, but will try and get if fixed if not too expensive. 

  • ADP1963
    ADP1963 Forum Participant Posts: 1,280
    1000 Comments
    edited March 2021 #5

    As Tricky say's it is crucial you remove the cover to ignite the fridge on gas.  Good luck.

  • EasyT
    EasyT Forum Participant Posts: 16,194
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    edited March 2021 #6

    seems most likely 

  • Fozzie
    Fozzie Club Member Posts: 550 ✭
    500 Comments
    edited March 2021 #7

    I can not remember ever having to remove a cover for the fridge,water heater yes,but not fridge.

  • LLM
    LLM Forum Participant Posts: 1,555 ✭✭
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    edited March 2021 #8

    As other have said a thermo couple problem.  You should see a wire being heated by the gas flame.  That is the sensor tip if it is glowing red then the actual TC may have failed if it is not being heated, maybe because it has moved or been bent away from the flame you can gently bend it back into position.  Worth a look and try.

  • davetommo
    davetommo Forum Participant Posts: 1,430
    edited March 2021 #9

    I think the cover that is meant is the winter vent cover

  • SteveL
    SteveL Club Member Posts: 12,303 ✭✭✭
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    edited March 2021 #10

    Our winter vent covers don’t seal the opening 100%, there is still a narrow opening. They are designed to be left on if the temperature is below about 6 degrees.

  • HamishT
    HamishT Forum Participant Posts: 10
    edited March 2021 #11

     Thank you triky Auto - the grille I mentioned was the grille (of which there are two) which ventilates the fridge externally so that's not inhibiting the flow of gas.  But thank you for your quick response.  Sounds like it may be a thermocouple or the PCB.

  • HamishT
    HamishT Forum Participant Posts: 10
    edited March 2021 #12

    Thank you.  Yes, the grille I mentioned is for external ventilation.

  • HamishT
    HamishT Forum Participant Posts: 10
    edited March 2021 #13

     Thank you for looking at this.  Any idea if replacing the thermocouple is difficult?  It might be worth me doing this and then if it doesn't work it could well be the PCB.

  • HamishT
    HamishT Forum Participant Posts: 10
    edited March 2021 #14

    Our service people quoted £350 to replace both the thermocouple and the PCB.  Which does sound expensive to me!  Makes me inclined to have a go myself, at least to start with.

     

    Thanks for your reply.

  • HamishT
    HamishT Forum Participant Posts: 10
    edited March 2021 #15

     Thank you LLM.  I'll see if I can get the fridge out so I can access the TC more easily (it doesn't look too accessible from the external grill).

    Any idea how easy it is to get a standard fitted fridge out??

    BTW, your motorhome looks great!

  • commeyras
    commeyras Club Member Posts: 1,853 ✭✭✭
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    edited March 2021 #16

    An obvious point but are you continuing to press in the button for about 30 secs after the burner has lit?  Can you get at the burner from the lower exterior grill?  If you can, you may be able to give it a clean and remove any rust/dirt which may have gathered there.  Anything to save having to remove the fridge and replace the coupling.

  • LLM
    LLM Forum Participant Posts: 1,555 ✭✭
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    edited March 2021 #17

    Not my van Hamish, just a dream, one day sometime never I suspect.  Mine is far more modest. 

    You should be able to access the bit of the TC I mentioned immediately above the flame.  Probably easily seen by removing the lower external vent.  

  • dave the rave
    dave the rave Forum Participant Posts: 806
    500 Comments
    edited March 2021 #18

    There is a specific gap for probe to burner on those fridges,The probe only needs to be a fraction "off" for it not to work properly.If you can remove the shield without removing the fridge you will be able to see/adjust the probe whilst the burner is alight.Well worth a try but you will need to be outside working whilst a.n.other is operating the control.

  • HamishT
    HamishT Forum Participant Posts: 10
    edited March 2021 #19

    Thanks LLM.  A man must have a dream...

     

    I'll have a poke around outside and see what I can do.  Thanks for your help!!

  • HamishT
    HamishT Forum Participant Posts: 10
    edited March 2021 #20

    Thanks for this nonplussed.

    A local dealer told me the specific distance was exactly the thickness of a pound coin!  Time for me to do some work on the burner, I think.

    Thanks for your input!

     

     

  • LLM
    LLM Forum Participant Posts: 1,555 ✭✭
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    edited March 2021 #21

    This video my help you but I would hope that you can access the back of the fridge / gas burner through the outside lower vent hole and not have to remove the whole unit.  Good luck.

    Video

  • LLM
    LLM Forum Participant Posts: 1,555 ✭✭
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    edited March 2021 #22

    Just an overnight thought.  Is the gas shutting down because with all this cold weather the fridge is already down too or below the set / required temperature and no further cooling is required.

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