Cenral heating fuse keeps blowing

Discussion in 'Plumbers' Talk' started by Dereekoo, Jul 18, 2012.

  1. Dereekoo

    Dereekoo Member

    For whatever reason the the fuse in the power feed to the central central heating blew. I have replaced it a couple of times but it blows soon as the power is switched back on. When it does blow there is an almighty bang from the Landis controller with the screen  lighting up for a few milliseconds. I have turned the boiler to off,put cylinder thermostat to its lowest setting with tank heated by immersion, put room thermostat down to zero and put controller HW and CH settings to off but the fuse still blows and I get the bang. I would have thought if the controller had died it would just just play dead. I thought about just replacing the conroller with a suitable unit but got visions of a big bang and u/s new controller.
    Other than calling on the services of a heating engineer has anyone got any thoughts/guidance. Thanks for any help
     
  2. G Brown

    G Brown New Member

    Yes. You have a major short . Get it professionally fixed - and if you really are on out of date fuses then get your consumer unit updated too.
     
  3. Spooner

    Spooner Administrator

    Gosh that's jolly poor show dear boy, are you using a 3 or 5Amp fuse my good man??
    Is there any other item in your home not operating, can I enquire??
     
  4. Dereekoo, very hard for us to diagnose the problem from here.

    As I think you've correctly surmised, the CH&DHW controller should isolate the power to the whole boiler system - room 'stat, diverter valves, and boiler itself; it's the first link in the electrical chain. However, your boiler (what make/model is it?) will very likely also have it's own dedicated mains supply as well as the 'switching' supply from the controller.

    So, with the controller completely offski, that should isolate most of your system. So, it's possible that the boiler itself has the 'short' in it. The other most likely candidate - since the fuse blows even with the controller off - is the controller itself. But there's very little in there that causes fuses to blow - not much that can 'short' in that manner.

    This is just a guess, then - blame the boiler. Of course, your system could be wired differently...

    Unless you are competent with a test meter, I think you'll struggle to locate the fault.
     
  5. Spooner

    Spooner Administrator

    As DA has said, you should only attempt to find the a fault like this if you're able to use a multimeter and know what you're doing.
     
  6. tom.plum

    tom.plum Screwfix Select

    welcome home friend, there's a nice chap waiting for your advice on plumbing, he'll be along presently, his name is master plumber palava, have fun.
     
  7. Dereekoo

    Dereekoo Member

     
  8. Spooner

    Spooner Administrator

    Cheers Tom, gosh it's been a while. I've been in Prison for the last few years, well, it felt like it over on DIYdoughnuts...........
    Any of the old gang still around, I see a few.  What about Elvis, has he been found out yet & is back on his Milk Round??!!
     
  9. Captain Leaky

    Captain Leaky New Member

    Elvis does pop his head in occasionally....he's not 'doing' boilers now ;)
     
  10. Dereekoo, what type of programmer is it? Since you mentioned it 'lights up briefly', I'm guessing it's an electronic type with a digital display? Good chance, then, that this is secured on to its backplate with a single screw on the underside - slacken this screw and the programmer will pivot up from the bottom and can be lifted right off the wiring backplate. EXPOSING POTENTIALLY LIVE WIRES... So only do this when the power is completely isolated.

    Anyways, I'm thinking that if you do this, then you really have isolated everything except the boiler itself. Shove in a new 3A fuse, turn power back on - and stand back...

    If fuse blows, then it's almost certainly the boiler at fault.

    But only do this if you are 'happy' about doing it...
     
  11. Spooner

    Spooner Administrator

    Ah!!  What too much of a challenge eh?  Oh well, I guess when your biggest daily challenge is two pints of Gold Top & a carton of yoghurt.
     
  12. palavaman

    palavaman Well-Known Member

    This delta t bloke sounds farmeliar.
    I betta ask him sum plumbings qwessions.

    I have just fitted a washing machine at a customers haws. Trouble is customer says it keeps leaking at the valve end.  She says she is going to cancel the cheque she paid me. How can I stop the valve for leaking?
     
  13. graceland

    graceland Active Member

    Hey man, Elvis is in the building!! To settle your summations, I took voluntary redundancy and a nice few quid before the company went tist up anyway! I was caught in a trap, but I walked out, because I love you all too much baby!
     
  14. Spooner

    Spooner Administrator

    Refreshing to hear from you again Pava, give my regards to your wife, I hope her thrush has cleared up?
     
  15. palavaman

    palavaman Well-Known Member

    Oh, is it really you dickies pullings?
    Yes, tompoms managed to clear that thrush from my missus. She did squeal a lot though.
     
  16. gib.son

    gib.son New Member

    have you got blue suede steel toe capped shoes?
     
  17. Crowsfoot

    Crowsfoot Screwfix Select

           Hope you didn't fall for the "dropping the soap in the shower trick" whilst you were over there doing your porridge Dicky !
           Welcome back old son !
           The forums prodigal son returns!!
           Tappy,
     
  18. joinerjohn1

    joinerjohn1 Screwfix Select

    The missus has got a new pair of open toe'd safety sandals for sale. I put them on Fleabay, but no takers yet. Thought a few lady plumbers might have shown a bit of interest. ;)
     
  19. When you children have quite finished with your playground banter, will ye gee the OP some advice? Ta much...
     
  20. Spooner

    Spooner Administrator

    Ah Tappy dear boy, how lovely to hear from you, I hope this finds you well & that highly paid medical team managed to lance that very large boil on your anus & you made a full recovery??
    Give my kindest regards to Mrs Tappy & your 15 youngins, I hope the family allowance is still keeping the wolf from the door?
     

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