Replace Horstmann Centaurstat 7 Controller with SMART Option

[Mushy1]

I want to upgrade my current Horstmann Centaurstat 7 heating controller with a new smart option. I have looked at several such as the Nest, Hive, Honeywell, Tado, and Netatmo but not sure which one is best and how they can be connected. I'm currently leaning towards the Nest but the wiring diagrams are not compatible with my current setup so any help on this would be very much appreciated. I have created an image of my wiring configuration in hope it helps with my question. Thank you

 

[ericmark]

I would not recommend Nest, unless open plan house or hot air central heating. But the big question is what you get for the money. Nearly all central heating is a compromise. So looking at the TRV first. The idea is only heat a room when required, my Energenie TRV was first attempt, also sockets, light switches, and energy monitors all on the same system, and one could use IFTTT (if this then that) to have geofencing with the TRV, it claimed to work with Nest, but in real terms didn't, and the anti hysteresis software was OTT, so to get room to 20°C at 8 am one had to set it to 22°C at 7 am then 20°C at 8 am, which means geofencing would not work.

So the far cheaper eQ-3 or terrier i30 TRV heads would do a better job to the Energenie head, I got eQ-3 bluetooth heads at £15 each, but since brexit the price has gone up.

The Drayton Wiser heads claim to have algorithms which work out how long it takes to heat the room, so can move from an eco to comfort setting far faster, but also cost more. There is also EvoHome and Tado. Hive is an odd one out, with no ability to use OpenTherm, but mainly boilers can't work with OpenTherm anyway so may not be an issue.

If looking for the best, than likely the Myson iVector fan assisted radiators are the way to go, fast response times, can heat and cool, not effected very much by furniture in front of them, and with a 5 speed fan once the room is warm can hardly hear the fan. But once you look at price, think you will look for something cheaper.

At £15 - £80 for the TRV heads, and with this house I have 18, that has to be the big cost, so step one is what do you want to spend on the TRV heads?

I call it near enough engineering, the more you pay for the heads, the easier to set up, no point getting all heads which will not work with wall thermostat, however likely you can mix, so so many are stand alone, and so many work with wall thermostat, which is more like a hub than wall thermostat.

 

[EFLImpudence]

I am having trouble following your diagram with no accessory connections shown.

This looks like what your should be:

 

[EFLImpudence]

More likely this one:

 

[Mushy1]

Thanks for responses, still confused on the basis of whether its an 'S' or 'Y' plan system. From responses it looks like the nest isn't the best option so just wondering if there is a recommendation. Hive, Tado, Honeywell Netatmo? Any guidance would be appreciated, thank you.

 

[flameport]

Regardless of what mess of wiring you may have now, the installation is the same.
All existing timer / programmer / thermostat are removed.
New device replaces what is shows as the 'time controller' in the wiring diagrams
A link is required where the old thermostat connected, between 4&5.

 

[Mushy1]

Thank you, so I just need to put a connecting wire from 4 to 5 to and simulate the thermostat connection?

 

[EFLImpudence]

...but your existing Horstmann is a battery operated programmable room thermostat so -

if you have another room thermostat in place, perhaps someone has already done what has been suggested when fitting the Horstmann.

You will probably need a mains supply to your new device, depending on what you choose, and it would be better (to start again by) fitting the receiver near the supply or the boiler, otherwise you are going to end up with something of a mess and unnecessary redundant devices littering the room.

 

[Tommohawk]

Hi all - I know this thread is old but my query relates to the same controller and also Y plan so I've added to this thread. Hopefully thats sensible?
Anyhow, I want to replace Centaurstat 7 with Hive, and I dont have a separate external room stat, so presumably dont need to do the link wire.. can someone confirm please?
Also, the Centaur stat is single channel - my hot water is controlled on a separate timer on the boiler. Can I use the existing wiring to control a twin channel Hive to time the the hot water? I've scoured the net and cant find anything on this!
Grateful for any help?
thanks, Tom

 

[Tommohawk]

Just been giving this further thought and I think I'd be better off replacing the EP2 programmer in the kitchen rather than the Centaurstat 7. That way I can directly control the hot water too. The stat could then be decommissioned. (Currently the EP2 times the HW, and the CH is set to on full time, leaving the Centaurstat to do the CH timing/temperature). Does that make sense?

 

[CBW]

Yes replace the EP2 with Hive, might even be same backplate, decommission stat or link wires.

 

[Tommohawk]

Brilliant thanks! Just to be 100% clear, once Ive removed stat do I need to effectively link what would have been stat pins, eg 4 and 5?

 

[CBW]

Brilliant thanks! Just to be 100% clear, once Ive removed stat do I need to effectively link what would have been stat pins, eg 4 and 5?

Yes, to complete the circuit

 

[Tommohawk]

Excellent - -thanks again!