Question Smart Thermostat

sam spade

Active Member
Hi, I am thinking of trying a smart heating system. I have a combi boiler, can someone please have a look at the photos of the wiring within the current thermostat and advise?

I'm hoping it's just a case of swapping out the old thermostat?

Thanks in advance.


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Well-known Member
Does the heating and hot water in your house just come from the one combi boiler ? If so, then that's a pretty simple system with a simple type of wired thermostat, so I would expect switching over to a smart thermostat to be fairly straight forward. If the house is split into different zones (any other thermostats ?) or you have any additional hot water storage, then things could get a bit more complicated.

Which smart thermostat were you thinking of ? I replaced the thermostat on my Worcester Bosch combi boiler with a Google Nest thermostat without any issues. Having had it for over 4 years now, there's no way I could go back to a non-smart system !

I'm not sure how other smart thermostats are set up but, in the case of the Nest thermostat, it isn't quite as simple as swapping the old thermostat for the new one however, as the thermostat itself is wireless and there's an additional bit of hardware called a 'Heatlink' that sits in the system in-between and communicates with both the thermostat and boiler.

It may be that some of the other smart thermostats do allow a direct replacement of the old thermostat with the new one, so that might be something to consider if you want the simplest installation. You'd have to look into this though, as I'm not familiar with other systems - I'm fully into the Google 'eco-system' so the Nest made the most sense for me and it is often reviewed as the best option.

If you are interested in the Nest thermostat, then let me know and I can explain a bit more about how it works.


Well-known Member
I use the Hive system. The controller would fit directly on your existing backplate (or you could swap it for the new one that comes with the Hive, they are the same. The thermostat is wireless and battery powered, so you can place it in the best place and no requirement to provide a 5Volt power supply that the Nest requires.

You don't need network access for basic set up and control but if you want to be able to set it up and control it remotely, you would need to have a home Wi-Fi network available.

sam spade

Active Member
Thanks mikej, yes, a combi boiler for both heating and water with just the one thermostat. I think you've confirmed what I was hoping ie the ease of replacement.
Having watched what seems like dozens of videos in YouTube re the nest and the hive I think I should be ok. Looks pretty straight forward (famous last words.)

Thanks John7, you've convinced me to go for the hive as it sounds suits my needs more 🙂


Active Member
I use tado and had the same wires setup as you. It was very easy to setup. I only need 2 wires. The other one wasn't needed

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