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Wiring when replacing DPST heating switch with Boost button

Discussion in 'Electrics UK' started by terraling, 14 Oct 2019.

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  1. AndyPRK

    AndyPRK

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    Are you trying to boost the Hotwater?

    Or heating ?

    Do you have a Heater and water thermostat ?
     
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  3. SFK

    SFK

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    1571170074941135645598.jpg


    Sorry, but on a bus.
     
    Last edited: 15 Oct 2019
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  4. ericmark

    ericmark

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    Great you have worked it out, but problem remains duel pole and no neutral.
     
  5. SUNRAY

    SUNRAY

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    Does your boost timer fit on a single gang back box?
     
  6. SUNRAY

    SUNRAY

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    Looking at your pic of both switches I see the 'water' switch neon is on with both switches off, I also see a blue wire behind the 'rads' switch. Is there more than in your wiring diagram? and how have you assertained the circuit diagram, ie how did you identify the wires?
     
  7. terraling

    terraling

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    It's not that there is no neutral, it's just that they don't seem to be wired to these switches, which effectively seem to just on/off the live feed to the boiler/water pump for the Water switch and boiler/rads pumps for the heating, presumably the neutrals are connected directly, outside the switches.

    In these shots you can see that there are plenty of other wires in the back boxes which are not connected to these switches. It's just difficult for me to follow where those go.

    My wiring diagram before is just reporting what I find with the multimeter, in the format

    L2 N2

    L1 N1

    Water heater...

    water.jpg

    Rads switch:

    heater.jpg
     
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  9. AndyPRK

    AndyPRK

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    or one pole turns the boiler on
    the other pole turns the CH pump on

    but the wiring looks too modern for it to be like that (gravity HW)
     
  10. SUNRAY

    SUNRAY

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    Are there any developements on this thread?
     
  11. ericmark

    ericmark

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    I seem to remember it was around 1995 that Part L building regulations came out and around 2004 when the colours changed for wiring so it would seem strange as said for the system not to have more control. However I looked at one boilers instructions 2007 where there was no thermostat on the wall, and temperature control was done with the TRV heads.

    There is a cable which seems to have been chopped so it seems likely at one time there was more control, however one would need to use a meter to work out what each cable does, not really some thing which could be sorted over a forum.

    I consider the wiring mess in this house for the heating, and wonder if it had been bought by a non electrician how they would have sorted it out, the plumber and oil fired central heating guy I found to do pipe work and boiler service did not seem to have much idea of how to wire.

    So it seems neutrals are available, I have found two pole push timers, but one pole has to be neutral, so only way I can see how it can be done is with relays, so it would seem a central heating programmer is likely the best option, I have the same problem myself, I want a relay to work part of the central heating, but it seems can't buy a simple self contained relay, I need to build it from adaptable boxes, din rail, relay base and relay. Then one looks at how to mount and look OK. Not so bad for me, room in cupboard next to boiler, but as to some thing which would look OK on the wall, not so easy.
     
  12. terraling

    terraling

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    I've hit a bit of a dead end, I thought replacing those switches with timer/booster switches would be straightforward and it was just a question of identifying which wire goes where, but it seems like there is more to it than that.

    I'm going to have to call in the heating engineer I've used before and get him to look specifically at this.

    Thanks everyone for your input, I learned a thing or two even if I didn't get it resolved.
     
  13. SUNRAY

    SUNRAY

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    Well it is do-able as long as there is the neutral available and the space can be created for a relay in the back box plus you'd probably have to do some soldering.
     
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