Replacing Honeywell ST9400C with Tado or alternative

[windsortg]

In my 3-bedroom semi-detached house, I currently have a conventional central heating system comprising of a:
- MAIN HE Condensing boiler (located in lounge)
- Honeywell programmer ST9400C (located in lounge beside boiler)
- Honeywell HCW80 (Y6630D1007) Battery Powered Wireless Room Thermostat (located in hallway)
- Honeywell relay/receiver HC60NG/R6660D (located in a bedroom cupboard beside the hot water tank, zone valves, and pump)
- a wiring box (located in the same bedroom cupboard where the hot water tank is)
- I believe I have a S-Plan setup with 2 x 2-port motorised valves controlled by the room thermostat and hot water cylinder thermostat (photo attached)

I am looking to replace this with the Tado Wireless Smart Thermostat Starter Kit V3+ with Hot Water Control, or an alternative smart system so that I can control the central heating and hot water remotely.

Assuming the Tado Wireless Thermostat Starter Kit V3+ is compatible, is it fairly straight forward to remove the Honeywell set-up and replace it with the Tado system? I would like to do it myself but there are a fair amount of wires.

 

[Stuckinarut]

Yes, often it just replaces the programmer (ST9400C) and then you need to decommission the thermostat or set to maximum, but in your case for complete easiness, you could join the 2 switch wires in the receiver. If you wanted it out altogether we can help with that too.

 

[windsortg]

thanks @Stuckinarut. From what I have researched, I think I need to:

1. follow the instructions from the Tado app on how to wire the Tado v3+ wireless receiver using the wiring currently going to the Honeywell ST9400C programmer
2. from the wire going to the Honeywell wireless receiver, to join the wire going to terminal A with the wire going to terminal B using a Wago connector, which is what I think you are stating where you say "join the 2 switch wires in the receiver"

Does that seem about right?

One thing I have read elsewhere is that some people have experienced problems with the Tado wireless thermostat staying connected with the Tado hub (which is connected to a router). They have experienced loss of connection at times between the hub and the Tado wireless thermostat. They have mentioned that the schedules are not kept locally (are kept on the Tado server) so you can wake up sometimes to find the heating hasn't switched on, or hasn't switched off

 

[Stuckinarut]

Yes, sounds about right. Maybe consider an alternative, several available, such as: Schneider/Drayton Wiser, Hive, Nest, I think Honeywell do one, Esi et al.

 

[windsortg]

thanks @Stuckinarut. Do you happen to know which specific one Honeywell do?

My Honeywell HCW80 wireless thermostat has stopped working which is also another reason to replace the current setup.

If the other brands you suggest are just as easy to set up as the Tado, and are as reliable and potentially cheaper , then would you recommend a particular one?

 

[Stuckinarut]

Honeywell T6/Lyric is their version but is dearer than most. I don’t actually have any experience with ones I’ve suggested

 

[ericmark]

so that I can control the central heating and hot water remotely.

Why, I have tried using geofencing, and it was a failure, what I would want is for the heating system to detect when I am 7 miles from home. As the nearest town is 8 miles away, but although Nest Gen 3 did turn on the heating, I was nearly home before it did, and so the only option was to either to manually turn it on, and I would forget, or to use a simple timer.

There is nothing to stop having many thermostats wired in parallel. So could have one in every room, so if any room cold the heating will run, and this is what Drayton Wiser in essence does with linked TRV heads, there is no reason to have a wall thermostat. I think Honeywell EvoHome does the same?

There are two very different approaches to heating, one is to maintain the temperature 24/7 which works well with under floor heating for example, the other is to heat only as required, inferred would do that nicely. But in the main we select a middle road.

It takes around ½ an hour for the boiler to fire up, and radiators to get warm, and at least another ½ an hour for that heat to get into the room, so for geofencing to work, one would need to work an hour away from home or more. The same applies to manually turning on the heating, unless you have fan assisted radiators, heating the house ready for your return home using an automated system, in the main means a simple timer.

One can, by selecting a room at a time, speed up the process, if one cooks a meal on return, to have a 10-minute gap between kitchen, dinning room and living room, get the rooms to heat up in that order, more than 10-minutes, likely the boiler will start to modulate, so the gain is lost. And of course delaying bedroom until 9 pm, will likely save money, assuming one retires around 10:30 pm. And not heating the office, or craft room unless one is going to use them.

But basic what I am saying is the TRV is king, and you need electronic TRV heads to set the time, and to ensure the boiler runs at 9 pm to heat the bedroom, the TRV needs to be linked. Yes my first electronic TRV heads could use IFTTT to be set to geo-fence, but since they did not link to boiler, rather pointless.

The Wiser TRV head claims to be smart, and work out how much ahead of time it needs to turn on to get the room warm at a set time. Not tried, so can't say if it works, but we are left with an either/or situation. Either geofencing or using smart algorithms, it seems unlikely we can use both.

So I would say select a system, and move towards it. Be it Hive, Wiser, EvoHome, Tado or another, the TRV and hub need to be the same make, basic fact is the router wireless is power hungry, so most TRV heads will use a hub and a system needing less power, so the pair of AA cells last longer, there are some which use zigbee, so may work with other devices, and control systems like Nest Mini or Alexa can control many systems, so although in my living room I have Energenie, Kasa and Wiser, a single command hey google set living room to 21ºC will set all three to 21ºC, and the same goes for Google home app on my phone. But my aim is over time to move to Wiser, now I have a Wiser Hub, that move is easy.

Before I used Nest Gen 3, well still use Nest Gen 3 and that controls my domestic hot water as well as hall temperature, Wiser at moment only does the living room. I made a mistake with Nest Gen 3, thought it would work with Energenie, it doesn't, USA Nest has remote sensors, so can do multi rooms, by not Europe version.

With an air B&B I can see why remote control is required, but with the standard home, central heating does not react fast enough to be worthwhile, yes I have just turned my heating up with my phone, but that is being super lazy, not walking 5 steps to the wall thermostat.