Thetford fridge not working on gas

Discussion in 'Fridges & Ovens' started by Bart, Nov 22, 2017.

  1. Bart

    Bart Funster

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    So i just though i would test the heater and fridge in the MH , thats when i discovered our Thetford fridge / freezer was not working and was giving an error code 9.
    So off i went outside and removed the lower grille followed by the metal cowling covering the burner unit , thats when i could see that the burner clearly lights nearly instantly but it only runs for like 20-30secs then it stops and produces the error code 9 on the lcd
    Note that all the time it is alight the electrode bit that produces the spark is constantly clicking away & sparking like the fridges brain has not realised that the fridge is in fact lit and it is still trying to light it with the spark. ( or is that normal ?? )
    here is a short video of what happens
     
  2. WillH

    WillH Funster

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    Thermocouple faulty or not in adjustment?
     
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  3. Bart

    Bart Funster

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    from reading that is what it looks like, but what part is the thermocouple ? , sure its not the part that produces the spark as well ??
     
  4. Tykatem

    Tykatem Funster

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    I wonder if it could be something as simple as a duff thermistor? It's located attached to the fins inside the fridge. Try disconnecting it, you'll find a connector on the upper part of the fridge. Once disconnected see if you're getting the same reaction from the burner.

    Pete
     
  5. WillH

    WillH Funster

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    Could be, my reasoning is that you seem to have a viable flame but the power card is not seeing it. Looking at the exploded parts diagram there is no separate thermocouple so it may well be incorporated into the spark electrode. Checking on the Thetford error code list they say it may be the power card, the electrode is a lot cheaper to try.
     
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  6. Bart

    Bart Funster

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    I'll try disconnecting the inside temp sensor or what ever you call it , I'll also check it with the multimeter when I have it out , we'll try :)
     
  7. WillH

    WillH Funster

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    Bart, have you had the fridge out before, it's a pain to say the least. Mines been out three times now, best to have an upturned milkcrate handy to place it on.
     
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  8. PhilandMena

    PhilandMena Funster

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    What does error code 9 mean ! I find it odd it's still trying to ignite after ignition!
     
  9. Bart

    Bart Funster

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  10. Bart

    Bart Funster

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    I seen it in a video earlier , I will not be taking it out unless I have to.
    Does anyone know if Is it normal for the igniter to keep on clicking after the burner has been lit ? If not then that would definitely be some sort of sensor problem surely
     
  11. SandraL

    SandraL Funster

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    Found tnis on another website, not sure if it is same as yours but might be helpful.


    The system of having the same device provide ignition and sensing is apparently Direct Spark Ignition (DSI). "The heart of the system is the solid state ignition module that provides both the high voltage spark to ignite the burner, and then the means to monitor the flame. Once the
    burner is lit, a small electric current flows from the ignitor to the burner through the flame. The ignition module generates and monitors this electric current. The presence of the DC current indicates that flame is present. The ignition module keeps the burner solenoid fuel valve open as long as the flame is present. Should the burner flame fail, the ignition
    module reinitiates the high voltage ignition spark for typically up to 11 seconds (for standard modules). If the flame is not reestablished within the trial period, the ignition module closes the solenoid fuel valve, shutting off gas to the burner. In order to reset the ignition module and burner, power must be interrupted and restored to the burner"
     
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  12. dave newell lvs

    dave newell lvs Trader-Vehicle Services

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    Thetford fridges don't use a thermocouple, they use flame rectification to detect combustion. Once the flame is lit the ionized has in the flame conduct to earth from the electrode. The reason yours is still sparking once kit is that the flame failure circuit has failed. This might be due to a dirty electrode or the burner itself may be partially obstructed causing the flame to not hit the electrode, if none of the above them it's likely to be the main pcb which is about £150 or so.

    D.
     
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  13. PhilandMena

    PhilandMena Funster

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  14. Bart

    Bart Funster

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    YAY its working ,,, well atm anyways.
    @Tykatem thanks it looks like was either a bad connection , but more likely a faulty sensor inside the fridge mounted on the 5th cooling fin from the right, as when i disconnected the sensor ( luckily its just connected by a molex connector inside the fridge for quick elimination ) and i started the fridge it light up as normal on gas and kept running for a min or two until i stopped it manually however i did get an error 13 , which was due to me having the sensor unplugged.
    So next i re plugged back in the sensor and turn on the fridge and low and behold it lit and the igniter stopped clicking.
    @dave newell lvs although i did notice when i ran it with the sensor unplugged after the burner had lit up ok i did hear/see the igniter re click the odd time , so i think next decent day ill take out the burner and clean it and reinstall it.

    Re testing the sensor using a multi meter using the resistance setting , is there a figure i should be looking for ? ( btw im new to using my multi meter so take it easy on me :)
    my multi meter is :
     
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  15. tonyidle

    tonyidle Funster

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    The electrode bracket is slightly bent lifting the electrode slightly higher than it should be. I doubt that it is all that sensitive but it's worth removing the electrode & straightening the bracket. You can't test the electrode with anything: it's a lump of metal on the end of a wire. If it sparks OK it is OK.
     
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  16. Bart

    Bart Funster

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    @tonyidle Thanks tony for spotting that bent bracket , re the testing , i'm not looking to test the electrode sparky thingy , i'm looking to test the temperature sensor that is mounted inside the fridge.
    Thanks
     
  17. The Wino

    The Wino Funster

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    Ours played up in France last year would not stay on the gas option on the control panel kept going back to mains what sorted it was just disconnecting the power lead behind the grille and after a few seconds reconnecting been fine since!!. Might be worth trying before starting to take bits off

    David
     
  18. Tykatem

    Tykatem Funster

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    If you should need to replace the thermistor? The part No is 623077 and can be easily obtained from ebay for about £18.
    https://www.ebay.co.uk/itm/Thetford-SR-Fridge-Thermistor-623077-/202117880727?hash=item2f0f2a1b97

    Pete
     
  19. Bart

    Bart Funster

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    @Tykatem thanks Pete , i think i will order one and keep it as a spare as i'm sure it will cost me 50 Euro and take a week to source if it packs in while in europe.
     
  20. Bart

    Bart Funster

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    LOL Typical i went out today to light the fridge to check it and yes you guessed it , it never worked and i got error code 9 again , so i unclipped the sensor from inside the fridge grille and placed it into my hard and blew on it to warm it up,and surely it worked one working fridge :) , so ill order one of them sensors today.
     
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