Is this live?

[LennyM1984]

We've recently replaced our boiler controller with a Wiser system and so I thought I'd remove the old, battery powered thermostat from the wall (we are stripping the paper and redecorating)

I was expecting to find 2 wires which would have gone to the now disconnected controller. What has thrown me is that there is also an earth stuffed behind that box and a quick scan with my stud finder (which can also detect live cables) had it beeping.

It's there any reason why this would be live? There's a socket on the floor beneath so I'm wondering if they have just fed the thermostat wires down the same path and that's what I'm picking up

[Regbuser]

That'll be supplied from the CH wiring centre, a rats nest of a box generally located somewhere twixt the old CH controller, HW cylinder, and zones valves, usually in the loft..

[Richard-D]

It is fairly common to find a thermostat left wired in that needs to be left turned up to allow the modern control system to work. I've had this in two houses.

[LennyM1984]

Richard-D said:

It is fairly common to find a thermostat left wired in that needs to be left turned up to allow the modern control system to work. I've had this in two houses.

Weirdly a bit of further experimentation would suggest that is the case here!

[ARHarh]

just join the wires together, either at that end or at the other end where they enter the boiler junction box.