Is my thermostat wiring compatible?

[Dannitan90]

I need t make sure the current system is compatible. The nest online guide asks me to identify cable for this, but mine don’t have labels.
I will add a picture when I work out how, but in the meantime I have:
6 phoenix connectors in 2 x blocks of 3:
White cable (no label on PCB)
No cable (no label on PCB)
Brown cable (no label on PCB)

Black cable (1, on)
No cable (2, off)
Brown cable (linked from other brown cable) (3, COM)

Thanks for any help

[Lance_L]

Hey Dannitan90,

Thanks for reaching out to the Community. I’d be happy to help you with this. Let’s check it out.

A few questions: which country are you located in? What type of heating or cooling system do you have? What is the make and model of your HVAC system and existing thermostat?

Here’s a handy guide to help you identify a thermostat wire.

Keep me posted.

All the best,

Lance

[Dannitan90]

Hi Lance, I’m in the U.K. (England), I have a manual rotary dial thermostat from a combi-boiler. I don’t know what make it is as there’s nothing written in the thermostat. I have a picture of the wiring but I don’t see a way to upload it here. 

thanks.