Thorn Apollo boiler problem, can anyone help?

Discussion in 'Plumbers' Talk' started by thekitchendesigner, Jan 8, 2006.

  1. thekitchendesigner

    thekitchendesigner New Member


    New to the forum, so hi!

    I have a Thorn EMI Apollo boiler, at a guess about 10-15 yrs old. This morning it didnt come on for heating, and we have since discovered the pilot light has gone out. We have been able to re-fire the boiler, but it only lasts about 10-15 minutes, before what i believe to be the gas valve, trips and the boiler shuts down.

    does anyone know the cause of this? We still have gas, and there is no problem with the power supply to the boiler.

    Heres hoping someone can help!

    Many thanks,

  2. try lighting the pilot without switching the heatinh/hw on... test like this for an hour... if it still shuts off will give a better of idea of what may be wrong.

    Chances are, it only the thermocouple, also the pilot burners are prone to distortion over the years.

    could also be a overheat problem, and if you're unliky the gas valve!

    You'll need to get a Corgi guy in to check out these posiblities.

    Let us know where you are, mayb one of the corgis on here could help.
  3. thekitchendesigner

    thekitchendesigner New Member


    Thanks for a quick response! I'll try lighting the pilot again without then turning the heating on, and report back!

    I'm in Trowbridge, Wiltshire, if there is anyone local around!


  4. thekitchendesigner

    thekitchendesigner New Member

    Right, have tried a few times to light the pilot, and then not turn on the heating. Pilot light doesnt seem to want to stay on at all now!

    i press in gas valve & ignitor, and when it does light, i have to keep gas valve held down for 20-30 secs before releasing it gradually. I do this, and right at the end the pilot light goes off!

    Does this help any more with diagnosis?


  5. doitall

    doitall New Member

    Which model apollo you have a choice of about 20.

    gc No will do

    Most likely problem is gas valve or pilot flame
  6. thekitchendesigner

    thekitchendesigner New Member

    There isnt anything that says which it is. Previous house owners left no instructions.

    Only thing i could find under where the gas valve is is this:

    Type V4600A 1023 2

    any ideas where else to look?
  7. its fine...

    70% sure it thes theremocouple
    25% the pilot buner needs replacing/injector cleaning
    5% i could be wrong!!!! :)
  8. thekitchendesigner

    thekitchendesigner New Member

    hopefully you are right though!

    roughly how much do thermocouples cost to replace? I know you cant say exactly, but are we looking under £50, up to £100?? Never had to have anything replaced with boilers before!

  9. doitall

    doitall New Member

    Boiler model and gc number is on the plate inside the door

    Thermocouple has an overheat connection which could also be a problem.

    if the pilot stays alight then the thermocouple is ok.

    need the number
  10. if its only the thermocouple/pilot then £50 should be about right...

    I'm pretty sure its not actually overheating, but as DoItAll says it could be a faulty overheat stat as well...

    probally best to change all 3... Should be less £100 all in, hopefully closer to the £50 tho.

    shame you're not a bit closer!
  11. doitall

    doitall New Member

    We got guys live in trowbridge, frome, melksham, westbury and god know where else spike.

    lets find out whats wrong first, may be something simple like re-setting the gas valve.

    thats the grey knob, turn it in the direction of the arrow and wait 3 mins or till you hear it click, then light the pilot.
  12. thekitchendesigner

    thekitchendesigner New Member

    i'll try that. currently, all settings are to 'off' and mains to boiler off. Can i still do the reset like this?

    Found some more numbers, but no plate - i know what kind of thing you mean, like the ones on ovens, fridges etc.

    there are 2 metal tags attached to the boiler, one has 8409 on and is small, and one has 260587 and is longer.

    on the lighting instructions on the inside of the removable front panel, there are some numbers at the bottom of the sheet.

    one is JWS 0583 and the other is 402C108.

    Do they mean anything?
  13. doitall

    doitall New Member

    No according to the gas valve number you have the 40B GC number 41-789-79

    It seems to be the only model with that valve
  14. doitall

    doitall New Member

    Sorry yes you can light it with the electric off.

    on the thermocouple about half way along theres two wires coming off, temporarily bridge them with a piece of wire and see if the pilot stays on then.

    post an email address.
  15. thekitchendesigner

    thekitchendesigner New Member
  16. 8409 boiler manufactored sept 1984

    the data plate is on outside of silver meatl casing, just above the two numbers you quoted.

    to access, you need to undo one screw which hold white case on at center bottom of white case, it'll then lift off.
  17. doitall

    doitall New Member

    mail on its way
  18. Kimbers64

    Kimbers64 New Member


    I'm a single mum and my Apollo boiler has been doing just as on the first page describes. My heating guy came out did a full service and told me the boiler is old and it could be a number of things but he is not interested in TRYING to find out what it is. He's changed the thermocouple but already it was not that. He said he could spend a few hundred quid of my money replacing what you say here and it not be any of them, needs a new boiler and I don't have £2,000 right now. My son is 6 needs bath etc and so hopefully heating man is coming out again this Saturday to see if it's any of these things you all say it could be here. I get the pilot to light then 5 mintues it clicks off and I have to wait turn it all off and try to light it again. He gave it all a good clean etc with the service and had it on high and continuous and it worked that night then following morning it was off again.

    Any further suggestions would be appreciated.

  19. Dick Puller

    Dick Puller New Member

    If they are Thorn Apollo's then that's the oldest model of Apollo & could be 20+ years old.
    The Apollo is a simple enough wee boiler, with a limited number of controls. With the high temperature cut-out being one of the most common faults, as said. This intercepts the pilot in a couple of ways, but given that's it's a Thorn I'd say it be via two connections as stated above. You both need a Corgy RGI, who knows the appliance.

    Sorry, but you also both need new boilers.
  20. tetleyman

    tetleyman New Member

    Kimbers64,if you are a single mum and on certain benefits you may qualify for a warmfront grant for a new boiler not 100% sure but worth a try

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