Nest 3rdGen & Vaillant ecotec exl 385

[kzl]

Hi,
I have just connected Nest Thermostat 3rd Gen to my Vaillant using this diagram:


Am I able to connect Thermostat to the wall wiring by replacing my old thermostat:


Or does it have to be connected to the usb power?
TIA

 

[Deleted member 267285]

If the Vaillant is wireless (looks it to me) then usb, if it’s wired, then you should be able to swap.

 

[kzl]

Thank you. Vaillant is wired, at the back of nest says not to connect it to 230V power therefore wasn't sure if I can replace it. Anyway seems it's not responding at all anyway so need to check the wiring again or i'm doing something else wrong

 

[ianmcd]

show a pic of the facia of the boiler

 

[kzl]

 

[Deleted member 267285]

You’ve got the eBus still connected and a 230v room stat connection. So unfortunately you can’t wire it, unless you take a separate wire from heat link to the Nest, so would have to be the usb otherwise.

 

[kzl]

Thank you. So seems like the heating isn’t working. I can hear boiler making clicking noise (starting up) when I turn the heating up with nest or turn it down but radiators aren’t getting hot at all. What could be the reason for that?

 

[Deleted member 267285]

Have you removed the eBus wiring? (Black and grey on left hand side)

 

[kzl]

I have not. I didn’t realise I have to. Only removed the rt. I’ll try tomorrow. Should that fix the problem? Tia

 

[Deleted member 267285]

Yes, otherwise it’s still looking for this.

 

[ianmcd]

As @CBW says, you will have to disconnect the Ebus or the boiler will constantly look for the old controller

 

[kzl]

Just only managed to fix it today. Done as you guys adviced and it all finally seems to be working. Thank you for your time and help!

 

[ianmcd]

A little bit of polite advice , if you need help post pics of what you actually have not a web found pic of someone elses, if you had posted a pic of yours before asked to , it would have been sorted immediately