Replacing Basic Dial Room Thermostat with Digital

[TCUK75]

Hi,

I've done some research on this question, looked at the wiki etc however I'm still not 100% clear on this and obviously don't want to risk damaging something so would really appreciate some help/guidance with this.

I'm replacing this;

Which has;
Yellow/Green - Earth
Black - Switch?
Brown - Live
Grey - ? Not currently connected

With a Home Expert Digital THR840DUK;

I think I just need to connect Black to A and Brown to B. And I can ignore Earth as this doesn't need to be connected? What's the grey wire please?

Would really appreciate some guidance on this from you.

Cheers

 

[EFLImpudence]

Black to A and Brown to B.

No, the other way round - assuming brown is live which is likely.
It doesn't actually make any difference in this case but it would if anything were connected to C so just as well do it right.

And I can ignore Earth as this doesn't need to be connected?

Yes, position safely out of the way.

What's the grey wire please?

Depends what it's connected to at the other end.
Maybe nothing - but could be used for something if ever needed.

 

[Taylortwocities]

Insulate the grey wire by putting it into a bit of choc block. Better than let it wave around and maybe touch something. It may be connected to something at the business end.

 

[TCUK75]

Perfect!

Thanks very much for the advice.