Grill won't stay lit

Crookie
Crookie Forum Participant Posts: 19
edited September 2018 in Caravans #1

We have a Bailey Unicorn Cadiz with a Thetford Caprice Mk3 oven. The oven and all of the gas burners work perfectly and the grill will light but on releasing the control (even after pushing it in for several seconds) the grill goes out? I am therefore confident that it isn't not a gas supply problem and may therefore be a problem with the thermocouple. Does anyone know if this is something that can be fixed easily or if it could be some other problem that I haven't thought of?

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  • peedee
    peedee Club Member Posts: 9,386
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    edited September 2018 #2

    I have the same model and have the same problem, sometimes it is ok and others it goes out. I also suspect the thermocouple, possibly it is not being heated enough for whatever reason. It seems worse after grilling anything which splashes fat about like sausages.  I would be interested in further comments.

    peedee

  • lornalou1
    lornalou1 Forum Participant Posts: 2,169
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    edited September 2018 #3

    probably need the oven removing to get to thermocouple.

    https://www.inter-spares.co.uk/thetford/thetford-cooker-oven-spare-parts/ck13933-aspire/grill-thermocouple-en-3.html?gclid=Cj0KCQjw5s3cBRCAARIsAB8ZjU3O-gV-pWA-HK-lixtwnVuYijBkdKWtYSoDv2PnlJsgVSOwIgBrLLgaAoyCEALw_wcB

    is the thermocouple In the flame, if not would stop it working. light as normal and hold in knob and look at flame and see if it is. you could always bend bracket a little to get the full effect of the flame. when cooled.

  • rovinmad
    rovinmad Forum Participant Posts: 102
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    edited September 2018 #4
    Is it one that needs the hob lid to be up? If so, make sure it's pushed back properly.
  • peedee
    peedee Club Member Posts: 9,386
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    edited September 2018 #5

    My views mirror LL's but I wouldn't try bending the thermocouple. I think it is quite likely to break. My gas is off at the moment and motorhome laid up. Next time I use it I'll do as LL suggest before doing anything further.

    Don't think there is a safety interlock on the hob lid but will check that just in case.

    peedee

  • DaveT
    DaveT Forum Participant Posts: 174
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    edited September 2018 #6

    Same model and same problem. Gas thermocouple replaced - about £18 if I recall.

  • lornalou1
    lornalou1 Forum Participant Posts: 2,169
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    edited September 2018 #7

    peedee. I should have said bend bracket that thermocouple was fastened to, not the tc itselfwink

  • peedee
    peedee Club Member Posts: 9,386
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    edited September 2018 #8

    The thermocouple protrudes from the grill back plate into the rear gas jet. There is no bracket to bend. I suspect if this last jet is not performing as it should this is the cause of the problems being experienced. Alternatively, is the probe of the thermocouple being splashed with fat/burnt residue and effecting it's performance. Perhaps a clean up with an old tooth brush is worth a try.

    peedee

  • jennyc
    jennyc Forum Participant Posts: 957
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    edited September 2018 #9

    Thermocouples tend to become fragile over time. Bending then will very likely end in tears.

    Here’s a cure which has never failed me over the years. Mix detergent and water on your washing up brush and give the burner including the thermocouple, a firm but not brutal scrub. Rinse the brush and repeat with clean water. It may be a little slower to light while still wet, but once going it’ll probably stay on when you release the knob and work normally after that.

    The method will work on any burner, so long as the thermocouple hasn’t really failed. The only time we’ve ever had a thermocouple fail was decades ago, on a central heating boiler which had been serviced recently - quite likely weakening the thermocouple while doing so.

    Forget all lid advice, if the interlock is stopping gas then it won’t light in the first place.

  • bandgirl
    bandgirl Forum Participant Posts: 440
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    edited September 2018 #10

    We recently had a problem with the grill in our Thetford Aspire 2 cooker (fitted in our 2015 Swift Challenger).  It’s always been difficult to light but, once lit, has stayed alight.  Maybe there’s a general problem with Thetford grills?  Anyway, we went away in June and somehow the grill burner had dropped down from the fixing at the front.  I discovered it when I was using it, and the burner caught on the food as I put the pan back under.  I spoke to our dealer and they preferred to have the caravan in the workshop to check it out, for safety’s sake, and were willing to replace the whole cooker under warranty if it were necessary.  It turned out to be a simple replacement of the fixing, with no other damage to the burner.

    A long reply, apparently irrelevant, but I just wonder if the OP’s oven is still under warranty, and whether it’s safe to attempt to repair gas appliances oneself?

  • Phishing
    Phishing Forum Participant Posts: 597
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    edited September 2018 #11

    Mine does the same. Has done since new. Reported at both services and always performs flawlessly in the dealership. 

    Cleaning a thermocouple has no effect, it can be covered in stuff and still work. Cleaning the burner is a  good idea if the flame cone does not reach the thermocouple.

    I have noticed that a slight draught causes it to go out, even just walking past when it is on, but it does just go out on its own occasionally. 

    My thermocouple is right in the tip of the blue cone, glows red hot so position is not the issue. 

    Probably just poor design but Thetford are not going to own up. Some have had the controller changed and report improvement. 

     

  • ocsid
    ocsid Forum Participant Posts: 1,395
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    edited September 2018 #12

    I had this issue years back with another brand. What transpired there was the "push in" travel had over time become restricted, so the fail safe feature in the gas valve was not fully setting.

    I discovered this by pulling off the knob where then it worked properly. I cured it by pulling just a little spacer into the knob's stem hole [very small bit of crumpled aluminium foil]. This spaced the knob just further enough out from the fascia enabling the stem to be fully pushed in and set the fail safe feature.

     If the pushed in knob is clear of the fascia then clearly it would not be this problem. But if it seems to be restricting things a one minute test by pulling off the knob would determine if a similar issue is happening in your case.

     

  • Amesford
    Amesford Forum Participant Posts: 685
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    edited September 2018 #13

    likewise while having the caravan serviced the engineer pointed out that the grill would not stay a light he gave me a quick demo he then removed the knob put in some packing refitted it bingo

  • Grahame49
    Grahame49 Forum Participant Posts: 1
    edited April 2019 #14

    The problem with my Thetford Aspire 2 grill is that it will show a slight gas flame when the knob is pressed in, but as soon as you release the knob it goes out.  It seems to act very similar to the gas running out but I know it hasn't as the hob and oven work OK.  Strangely it worked in the morning perfectly but didn't work at all in the evening.  Is this likely to be a quick easy fix or a dealer fix.  Hopefully not the latter as I am in the Netherlands for the next 5 weeks.

  • commeyras
    commeyras Forum Participant Posts: 1,853
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    edited March 2019 #15

    How has this old subject reappeared on the opening page!!!!!

  • lornalou1
    lornalou1 Forum Participant Posts: 2,169
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    edited April 2019 #16

    was wondering that myself. spooky website this. surprised

  • BevnTerry
    BevnTerry Forum Participant Posts: 2
    edited December 2019 #17

    I've got exactly the same issue with the same oven,have had since new, 2015. You can replace the thermocouple without removing the oven as I have done this. It worked for a while then eventually stops working again. It seems to gradually get worse and worse until you have to hold the button in and burn your fingers. Nice 'safety' feature!

    The thermocouple does sit on a moveable bracket of sorts so you can gently bend the tip into the tip of the flame, but each time I do, it works for a bit then after a few days I think the heat anneals it back out of whack. Use a hollow tube to hold the thermocouple body, not the top.

    I've tried all the cleaning in the world and none of it helps.

    I think it's a design fault and we should all get together and demand Thetford fix it.!!

     

     

  • BevnTerry
    BevnTerry Forum Participant Posts: 2
    edited December 2019 #18

    Update having just tried to fix it. Again.

    Once I'd bent the thermocouple into the flame again it says on. So in response to a couple of other reports, I tried blowing on the flame to see how sensitive it actually is. The answer is not very at all!! I blew and blew and it stayed on. Eventually I managed to blow it right out and guess what? The gas kept flowing. I could relight it straight away just on the ignition.

    If I left it for about four seconds, I got the characteristic 'clunk' as it cuts off at which point gas stopped flowing. So the gas was flowing with NO flame at all so it surely can't be temperature related. I'm therefore suspecting a poor earth return and perhaps moving the thermocouple fixes it temporarily.

    Having replaced it myself (and being an electronic engineer) I was shocked how awful the engineering of it is so I'm not surprised. Will report back on how it goes, but this seems to prove its not about the flame position.

     

  • lornalou1
    lornalou1 Forum Participant Posts: 2,169
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    edited December 2019 #19

    and now it's done it again

  • ABM
    ABM Forum Participant Posts: 14,578
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    edited December 2019 #20

    I suppose that, by now, the gas has run out any way  smile

  • peedee
    peedee Club Member Posts: 9,386
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    edited December 2019 #21

    Nope but I still have the problem. I have just put it down to poor design

    I just persevere and keep re-lighting it. Eventually it stays on.

    peedee

  • Amesford
    Amesford Forum Participant Posts: 685
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    edited December 2019 #22

    This trick was shown to us by our mobile engineer a while back and its been ok ever since

  • hitchglitch
    hitchglitch Forum Participant Posts: 3,007
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    edited December 2019 #23

    There was a well known problem with the Thetdord grill a while back where it was recognised that the control knob shafts were too short. I recall finding reports online, printing them out and getting the dealer to change them under warranty.

  • bowleggs1
    bowleggs1 Forum Participant Posts: 9
    edited December 2019 #24

    Have you tried using the grill with the oven door open on my bailey Orion the grill will go out if the oven door is not open

  • lornalou1
    lornalou1 Forum Participant Posts: 2,169
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    edited December 2019 #25

    isn't the cadiz a seperate grill and oven so opening the oven door should not make a difference. the grill door would have to be open to operate the flame and stay lite.

  • Bobupandown
    Bobupandown Forum Participant Posts: 11
    edited August 2020 #26

    I replaced thermistor ok for a while then replaced the control brilliant for a while only needed seconds to stay on this trip very iffy .I am wondering if it is a bad earth connection on the body to bracket ? Will investigate when we are home 

     

  • Takethedogalong
    Takethedogalong Forum Participant Posts: 17,040 ✭✭✭
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    edited August 2020 #27

    Not in a caravan, but our living flame gas fire in house..... thermocouple and gas jets occasionally get clogged etc..... two perfect tools, an interdental flossing stick (look like miniature bottle brushes) to gently insert into gas jet to clear any debris, and a small fine grade emery board, to gently rasp around thermocouple to clean it. Works a treat for us, but the emphasis is on “gentle”. Worth a try..... but only if easily accessible.

  • Bobupandown
    Bobupandown Forum Participant Posts: 11
    edited September 2020 #28

    CRACKED IT  it is poor electric connection on the body of the thermocouple fitted independant earth lead to rear works brilliantly .

    This is after replacing thermo  and tap (not easy )

  • peedee
    peedee Club Member Posts: 9,386
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    edited September 2020 #29

    Thanks mine seems to have got worse over time. I'll have a look at what you suggest. Only thing that concerns me was if it was the earth surely that would effect the other ignition devices on the hob and oven, they work perfectly?

    peedee

  • DaveCyn
    DaveCyn Club Member Posts: 339 ✭✭✭
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    edited September 2020 #30

    Our grill played up whilst on a rally.

    Fortunately there was a very good mobile caravan mechanic on site who quickly found that the gas supply pipe was partially blocked by oily deposits from the gas.

    Took him about 30 minutes to strip it out and clean it through.

    No problems since.

  • cralphie
    cralphie Forum Participant Posts: 1
    edited October 2020 #31

    I have bought a new motorhome in 2018 and had several problems with grill and hobs not stay on. Under warranty I had the whole cooker replaced. The grill has just gone again. I heard someone say if you remove the knob from the grill at the front. Put a screw driver on the nut by the shaft and give it a tap with a hammer. Not too hard this will fix the valve not staying open. Did this now my grill is staying on. Chance who knows ?.