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  • FIRST POST
    • alistone
    • By alistone 12th Mar 18, 10:45 AM
    • 9Posts
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    alistone
    Save 100 wiring a Nest (3rd Gen) to my boiler
    • #1
    • 12th Mar 18, 10:45 AM
    Save 100 wiring a Nest (3rd Gen) to my boiler 12th Mar 18 at 10:45 AM
    Hey guys, my first post here but I'm hoping you can help me out. I'm an avid diy'er and my girlfriend is a terrible sleeper. Since the cold weather our boiler has been going mental turning on and off throughout the day/night. It's basically trying to keep up and the thermostat is a bit inaccurate (plus in a rubbish place above the radiator downstairs in our lounge).

    So to try and solve these problems I bought a Nest 3rd gen thermostat. I am quite fine with DIY but haven't done much wiring and don't really know my way around a circuit board or diagram so wondered if you could help. I would really appreciate it! I'm happy with the replacing of my current thermostat with the nest, It's the heatlink that looks a bit scary.

    So here's the breakdown:

    - I have a combi boiler, it's an ideal independent C4 and situated upstairs in our bathroom (the power comes from below in the kitchen, which is the white cable in the picture)
    - We have a single thermostat downstairs in our lounge
    - I have a 3rd generation Nest with the heatlink
    - I have 5 core flex cable
    - I have included a picture of the boiler and the current connections below

    I understand I need to run power to the nest and also connect it to the switch for turning on and off the boiler. I'm just not 100% sure which of the current setup I can remove (if I need to at all) and where to connnect the heatlink.

    I would really appreciate the help and would happily offer a reward for such galantry
    Last edited by alistone; 12-03-2018 at 10:49 AM.
Page 1
    • alistone
    • By alistone 12th Mar 18, 10:47 AM
    • 9 Posts
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    alistone
    • #2
    • 12th Mar 18, 10:47 AM
    • #2
    • 12th Mar 18, 10:47 AM
    It won't let me post pictures as I'm a new member If you think you can help please give me a nudge and I'll send you the pics. Thanks!
    Last edited by alistone; 12-03-2018 at 10:48 AM. Reason: add more content
    • alistone
    • By alistone 12th Mar 18, 10:51 AM
    • 9 Posts
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    alistone
    • #3
    • 12th Mar 18, 10:51 AM
    • #3
    • 12th Mar 18, 10:51 AM
    Links to the images, just copy and paste into your browser please...

    drive.google.com/open?id=1BJk3PWMiM9xfFwBZY2RK6nAGMuXgZVcw
    drive.google.com/open?id=1GlZ6sZY3zKhOr90NeUCAFwHBiKQW_wck
    • Poppycat
    • By Poppycat 12th Mar 18, 10:53 AM
    • 12,644 Posts
    • 9,571 Thanks
    Poppycat
    • #4
    • 12th Mar 18, 10:53 AM
    • #4
    • 12th Mar 18, 10:53 AM

    • alistone
    • By alistone 12th Mar 18, 10:57 AM
    • 9 Posts
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    alistone
    • #5
    • 12th Mar 18, 10:57 AM
    • #5
    • 12th Mar 18, 10:57 AM
    Thanks so much @poppycat
    • Debbie Savard
    • By Debbie Savard 12th Mar 18, 1:09 PM
    • 366 Posts
    • 314 Thanks
    Debbie Savard
    • #6
    • 12th Mar 18, 1:09 PM
    • #6
    • 12th Mar 18, 1:09 PM
    Can you double check the boiler model? Also is the white flex going to your existing thermostat?
    Last edited by Debbie Savard; 12-03-2018 at 1:11 PM.
    • Le_Kirk
    • By Le_Kirk 12th Mar 18, 2:44 PM
    • 2,686 Posts
    • 1,553 Thanks
    Le_Kirk
    • #7
    • 12th Mar 18, 2:44 PM
    • #7
    • 12th Mar 18, 2:44 PM
    Here are your pictures: -


    https://drive.google.com/file/d/1GlZ6sZY3zKhOr90NeUCAFwHBiKQW_wck/view
    https://drive.google.com/file/d/1BJk3PWMiM9xfFwBZY2RK6nAGMuXgZVcw/view
    • alistone
    • By alistone 12th Mar 18, 2:55 PM
    • 9 Posts
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    alistone
    • #8
    • 12th Mar 18, 2:55 PM
    • #8
    • 12th Mar 18, 2:55 PM
    Yeah it says "Ideal Indpendent C24" on the front of the boiler. I'm struggling to remove the old thermostat atm but I'm pretty sure there is a wire going into that too as it controls all of the prorammes for the boiler.
    • benjus
    • By benjus 12th Mar 18, 3:11 PM
    • 5,118 Posts
    • 3,156 Thanks
    benjus
    • #9
    • 12th Mar 18, 3:11 PM
    • #9
    • 12th Mar 18, 3:11 PM
    Remove the brown wire linking the 2 rightmost terminals together.

    Wire these two terminals to terminals 2 & 3 on the Nest heat link.

    More information here if you're interested: https://www.freeboilermanuals.com/assets/pdf/ideal/Independent-C24-C30-C35-Installation-Manual.pdf (especially page 27)

    Although I'm a bit confused as to how your current room thermostat is wired in, as I would have expected it to be connected to those two terminals.
    Last edited by benjus; 12-03-2018 at 3:13 PM.
    Let's settle this like gentlemen: armed with heavy sticks
    On a rotating plate, with spikes like Flash Gordon
    And you're Peter Duncan; I gave you fair warning
    • alistone
    • By alistone 12th Mar 18, 3:15 PM
    • 9 Posts
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    alistone
    Hmm interesting, I'll let you know when I remove it! But you think that should do the trick with the heatlink? So the "room stat timer" in the diagram in the manual you linked to? I imagine it also needs to be connected to live for power right?

    I'll give it a try
    Last edited by alistone; 12-03-2018 at 3:23 PM.
    • antilles
    • By antilles 12th Mar 18, 3:35 PM
    • 283 Posts
    • 139 Thanks
    antilles
    Looks like it already has thermostat connected to me via the black and grey wires (they appear to have brown sheathing pushed over them unless I'm mistaken) - are those the thermostat connectors? They usually have a link between them which looks as though it's already been removed. So could it already have a thermostat connected? Looks like 5 core cable to me.

    I'd bet those black and grey wires are connecting to a thermostat at the other end.
    • alistone
    • By alistone 12th Mar 18, 3:40 PM
    • 9 Posts
    • 0 Thanks
    alistone
    Got the cover off the current thermostat and it looks like this....

    drive.google.com/open?id=1WDdJoznmXUIjZ3zjD-Z6M8tg2Dml9h_F
    • benjus
    • By benjus 12th Mar 18, 4:00 PM
    • 5,118 Posts
    • 3,156 Thanks
    benjus
    Looks like it already has thermostat connected to me via the black and grey wires (they appear to have brown sheathing pushed over them unless I'm mistaken) - are those the thermostat connectors? They usually have a link between them which looks as though it's already been removed. So could it already have a thermostat connected? Looks like 5 core cable to me.

    I'd bet those black and grey wires are connecting to a thermostat at the other end.
    Originally posted by antilles
    Sorry, you're right... I originally thought that was an oversized loop of wire shorting out the room stat terminals, but I should have looked more carefully.

    Anyway, the instructions are the same - remove the wires connected to the 2 right most terminals and connect the 2 right most terminals to terminals 2 & 3 on the Nest heatlink.
    Let's settle this like gentlemen: armed with heavy sticks
    On a rotating plate, with spikes like Flash Gordon
    And you're Peter Duncan; I gave you fair warning
    • alistone
    • By alistone 12th Mar 18, 4:20 PM
    • 9 Posts
    • 0 Thanks
    alistone
    Ah ok thanks guys! So I disconnect the old thermo and attach the nest heatlink to terminals 2 and 3. Do I need to connect any other wires, for power to the nest heatlink for example? Assuming I can then simply remove the old thermostat downstairs as it won't be connected to anything?
    • Debbie Savard
    • By Debbie Savard 12th Mar 18, 4:32 PM
    • 366 Posts
    • 314 Thanks
    Debbie Savard
    IIRC the Heatlink needs 240V mains power
    • benjus
    • By benjus 12th Mar 18, 4:49 PM
    • 5,118 Posts
    • 3,156 Thanks
    benjus
    Yes, you'll need power to the heat link (terminals L and N), which you can take from the power supply to the boiler (the middle terminals on the boiler). Once you have disconnected the old thermostat from the boiler you should be fine to get rid of it. I'd always recommend using a volt meter or mains tester screwdriver to make 100% sure that none of the wires are still live.

    The other thing you need to consider is how to power the Nest thermostat. You can either use the T1 & T2 supply from the heat link (if you want to put the Nest thermostat in the same place as the old thermostat, you can re-use the existing wires for this), or you can use the USB power supply that comes with the Nest.
    Let's settle this like gentlemen: armed with heavy sticks
    On a rotating plate, with spikes like Flash Gordon
    And you're Peter Duncan; I gave you fair warning
    • alistone
    • By alistone 12th Mar 18, 5:09 PM
    • 9 Posts
    • 0 Thanks
    alistone
    Thanks that's great! I'll try this tomorrow. I think we'll go with the USB as the current thermo is in a silly place above the radiator downstairs!

    Will let you know how I get on
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