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Replacing Centaurplus C11 with Nest smart control

Discussion in 'Home Automation' started by HarryHeat, 23 Sep 2021.

  1. HarryHeat

    HarryHeat

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    Hi. I am hoping to convert my OFCH control to a Google Nest product but not sure if it is possible. Existing timeswitch is a Centaurplus C11 located in the kitchen (photos inc). There is a room thermostat located in the living room which backs onto the kitchen (inside carcassing in corner of kitchen near timeswitch). The boiler is outside.
    The crucial thing is to be able to control on/off remotely. The thermostat would be a nice addition but not too bothered (maybe a simpler/cheaper solution is out there for on/off)
    Additionally, the switch between hot water & central heating is a manual valve, again housed within the carcassing.
    What is best course of action? Can I just change the on/off now & then retrofit the thermostat and automatic valve later?
     

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  3. ericmark

    ericmark

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    I have Energenie Mihome TRV heads which can be remote controlled. However I found that the reaction time was a problem.

    Set to switch from 16°C to 20°C at 7 am ready for 8 am but the anti hysteresis software resulted in it being 11 am before it finally hit 20°C.

    So my old house had a Myson fan assisted radiator 3kW and a 4.5kW gas fire in living room, and with 7.5kW the room heated up fast, so no need for any remote controlls.

    So looking at speed.

    So let me give an example, with 50kW of fan assisted radiators and 25kW boiler you can set heating to heat rooms in sequence so most important rooms first, but with only 25kW of radiators rather pointless.

    The next point is cost to control v cost saved. One can spend £15k on the control, clearly you will never get that back.

    So my oil bill is around £400 p.a. if I switch off heating it takes around 4 hours before I realise it has been switch off, home does not cool fast, so in real terms not worth switching off for less than 8 hours.

    This clearly varies home to home. I look at people who fit underfloor heating, and wonder why, it is so slow to react, so what are you looking for as end result?
     
  4. HarryHeat

    HarryHeat

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    This is a holiday home, so key is to be able to remotely switch on and off heating during winter months when less often occupied, to prevent frost damage. Would also be good to be able to heat in advance of arrival.

    Would like to automate CH/HW valve but reckon that may be a bit more disruptive.

    Just not sure if the existing wiring is sufficient to run a nest or similar.

    Thanks
     
  5. CBW

    CBW

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    Yes you can add a Nest or Hive, but it seems you have a single channel timeswitch, so no hot water timed periods? What’s this manual valve you speak of - photo?
     
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  6. ericmark

    ericmark

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    The big question is protection from frost, I don't trust wifi to work 24/7 I find every so often it needs turning off and re-booting, so a parallel cheap thermostat (frost stat) can cure that problem. So nice to be able to monitor temperature, I had a pet cam able to do that, so could look around the room and see temperature. And to turn heating on/off a simple wifi switch will do the job, no real need for smart thermostat, however if not always you visiting then having a thermostat which is simple to manually adjust but also allows remote control does seem a good idea, Nest does this well, Hot water boost.jpg it is easy to turn dial and set, this thermostat ae235.jpg I had to keep the book with it to remind myself how to alter it, it was cheap and did a good job, not wifi, but my point is does not matter what it does, it needs to be intuitive, not much easier than turning a dial.

    So the Centaurplus C11 replaced with the Nest heat link, but the pictures don't really show how the thermostat connects to the Centaurplus, I used a multi-meter to ensure the cables I thought connected my timer to boiler did not go anywhere else, as clearly 230 volt AC on a thermostat designed for 12 volt DC will wreck it.

    Likely you can use the Nest e which does not need 230 volt power, however would not want to rely on batteries. So would say Nest Gen 3 better in your case even when DHW control not required.
     
    Last edited: 24 Sep 2021
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  7. HarryHeat

    HarryHeat

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    Chris - there is a red handled standard water valve near the skirting board in the kitchen (sticking out of that carcassing in the corner) upload_2021-9-24_12-24-53.jpeg which turns through 90 degrees to change from central heating to hot water being heated. I don't want to rip the carcassing just yet but if I thought it was an easy job to convert it to an electric valve that could be operated through the Centaurplus or Nest, then I would tackle it.

    Ericmark - Thanks for suggestions. Trying to establish if the wiring to the Centuarplus is sufficient to activate a Nest before I spend on it. Don't want it to turn into a house rewiring exercise. The Centaurplus is mounted on a block wall and tracked (upwards I assume) but two storey house so can't pick up wires for a look. They are only a metre apart on the wall, so I don't know if that suggests they are connected, or if the thermostat is linked directly to the boiler?
     
  8. CBW

    CBW

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    That seems a bit of an odd way to heat water and heating :confused: not something I’m familiar with.
     
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