Nest 3rd generation thermostat compatibility?

[diy94]

I recently got a Nest 3rd generation thermostat and the Nest stand.

I found that our current thermostat using mains power. After a quick online chat with Nest, the technical support told me that the Nest is not compatible with current system and ask me to return the item.

Is it possible to leave our current thermostat untouched, just use the Nest thermostat?

1. Timer
Only HW and CH on are wired, the OFF switches are not wired.

2. I believe I have a S plan system

3. Junction box

 

[stem]

I don't see why Nest would say that, unless you have told them something you haven't mentioned above.

If you search on this forum you will find lots of examples of folks replacing Drayton (aka Ivensys) programmers with Nest thermostats.

The Heat link requires a 230V as does the Drayton it replaces. The remote Nest thermostat can be powered by connecting it to the Heat link, or by using a separate plug in power supply.

Your photos show that you have what is known as a S-Plan system with two x 2 Port motorised valves; and as you correctly state the CH & HW off connections are not used. The Nest Instructions show the connections for this type of system.

 

[diy94]

Thank you stem.

I have seen other people with high voltage thermostat successfully changed to Nest. I think one reason the technical support said it is not compatible is because the official website said it is not supported:
https://nest.com/support/article/Ho...rk-with-the-Nest-Thermostat#works/?mode=guide
The technical support didn't ask me many questions. After confirming that my thermostat has stranded thermostat wires and on the thermostat is says 230v, he/she reply that Nest is not compatible with my current system and need to be returned.


I will try it during the Christmas holiday, if it is too complicated for me, I will call a plumber then. Any suggestions how much should I pay?

I don't see why Nest would say that, unless you have told them something you haven't mentioned above.

If you search on this forum you will find lots of examples of folks replacing Drayton (aka Ivensys) programmers with Nest thermostats.

The Heat link requires a 230V as does the Drayton it replaces. The remote Nest thermostat can be powered by connecting it to the Heat link, or by using a separate plug in power supply.

Your photos show that you have what is known as a S-Plan system with two x 2 Port motorised valves; and as you correctly state the CH & HW off connections are not used. The Nest Instructions show the connections for this type of system.

View attachment 154996

 

[stem]

I suspect something was probably lost in the conversation, and the link you posted starts off with saying something akin to you are looking at "customers in another country"......

When I have installed a Nest in place of a Drayton it has taken me no longer that 2 to 3 hours plus travel and less that £10 in materials.

 

[diy94]

It looks like I might made a mistake chat with someone from US. I will get in touch with the technical support from UK to confirm the compatibility issue.

 

[stem]

That would probably be a good idea. A Nest on an S-Plan is probably one of the most common applications in the UK.