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Wiring NEST 3rd GEN to Y-Plan, check my wiring please

Discussion in 'Plumbing and Central Heating' started by ProjectMat, 20 May 2017.

  1. ProjectMat

    ProjectMat

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    Hey guys,

    My wife and I have recently moved into a new house this month, and in doing so had the whole house rewired. The electrician came and removed pre-1977 Steel cable from the home and replaced the whole mains. In doing so he has removed all of the bottom side of my Honeywell 10 way junction box for my heating system and has left me with a fused spur.

    I took to the shops to buy myself a NEST (perfect opportunity I thought)

    I have followed the various diagrams for a Y-Plan system, and I have made every effort to wire this correctly. Please can you check over my wiring before I switch on. I intend to control both HW and CH

    Also, my Baxi boiler fitted by BG in july 2014 downstairs does not seem to be connected to the wiring upstairs in any way. No RF receiver/transmitter is immediately apparent, do I need to run cabling down to the boiler or does the pump somehow signal the boiler?

    Any help with this would be appreciated and treat me nice!

    Cabling from left to right on the image below, FUSED SPUR, TANK, VALVE, STAT, PUMP
    I fully intend to tidy up my wiring once confirmed.

    Thanks in advance for your help,

    Mat
     
    Last edited: 20 May 2017
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  3. ProjectMat

    ProjectMat

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  4. picasso

    picasso

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    You will need to run a cable from the junction box to the boiler, we need the model of the boiler to see if the pump has to wired to the boiler, this will show how many cores the cable will need to be.
     
  5. ProjectMat

    ProjectMat

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    Thanks for the quick reply mate.

    BAXI Solo 15 HE A

    I removed every cable from the 10way and rewired as they did not match any plan (n)
     
  6. picasso

    picasso

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    Your wiring looks ok but that don't mean anything as I am not there, (your responability to double check all is ok) if you have to run a new cable to the boiler use 5 core, you only need 3 core but if you have to change the boiler in the future the extra cores will come in handy.
     
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  7. dannyboi2003

    dannyboi2003

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    Get a pro heating engineer in to look at that ASAP mate, don't switch the power on!
     
  8. Agile

    Agile

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    I agree!

    I don't think what you need to do is likely to be easy for a DIYer.
     
  9. picasso

    picasso

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    Go on where exactly is the bit that's going to blow up ?
     
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  11. ProjectMat

    ProjectMat

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    Okay folks, thanks for the replies.
    Anyone see issue with the wiring now?
    Do the three cores from the boiler mirror the pumps? The boiler has its own fused spur downstairs now, idk if it had that before or not.

    Thanks for your help so far,
    Mat
     
  12. aptsys

    aptsys

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    The fact you have a CPC connected to a line conductor is not a good sign. Do not power the system up.

    edit: Is that the immersion heater connected directly to the relay on the nest??? Do not power the system up.
     
  13. picasso

    picasso

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    Yea my bad mate, I never noticed you had the immersion heater connected to the nest.
     
  14. ProjectMat

    ProjectMat

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    Right thanks guys for your help.

    I will revisit the wiring and get back to you with an updated picture.

    Thanks
    Mat
     
  15. D_Hailsham

    D_Hailsham

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    The "electrician?" should have wired the immersion heater (that's the silver box on top of the HW cylinder) to its own 15A spur fed directly from the main fuse board. What is the purpose of the empty box above/right the spur?

    You are holding the cylinder thermostat, which doesn't appear to have any wire connected. What's that all about?

    Did the "electrician?" tell you that he was not going to reconnect the heating system? If he didn't, you are entitled to assume that he was going to do the reconnection and should ask him why he hasn't finished the job you paid him to do.
     
  16. ProjectMat

    ProjectMat

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    The electrician provided me with one spur, which feeds into the ten way junction box. This is a direct replacement of the box you see empty, which I am told was a single socket with isolation switch.

    The stat I am holding in the image is one that requires no drilling or draining of the tank. Instead a small section of the insulation has been removed and it is held touching the metal tank with a wire that goes around the tank like a belt. It's just been taken off for the purposes of the picture mate. I assume the heat transfer between the plate at the back of the stat and the bare tank is sufficient

    Yes, I was well aware that he was not going to connect the system up. Along with many electrician's I have spoken to in the days after the rewire, there appears to be very few who can do heating electrical jobs. Apart from the lack of help on the heating front, which I was expecting, the man did a brilliant job.

    Mat
     
    Last edited: 22 May 2017
  17. D_Hailsham

    D_Hailsham

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    What was the immersion heater cable originally connected to? Even an electrician unfamiliar with heating systems wiring should know that an immersion needs it own 15A supply. The heating system needs a 3A fused supply, normally from the ring main.

    Who connected the immersion heater to the junction box? I hope it wasn't you!

    Why is the stat you are holding not wired into the junction box? It controls the temperature of the water in the cylinder.

    Your electrician may have done a brilliant job; it would have been even better if he had arranged for a knowledgeable heating engineer to deal with the heating side.
     
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