Replacing Drayton Thermostat with Digital Unit - Wiring Check Help

[ark sez]

My drayton thermostat (3-wire) stopped clicking so decided to buy a wifi digital thermostat. Digital thermostat dry contact is not wired to the live within the unit unlike the drayton. Can someone confirm my jumper cable position is correct? (i.e. does it matter which side of the dry contact (1) or (2) that the call (black) wire is connected?

Also, the yellow/green wire is con nected to the boiler pipes (earth wire), does it serve any purpose for the thermostat?

 

[Taylortwocities]

The way you have it in your diagram is correct, with a link between 1 and 4. The convention is for the line to be on the common connection of the make switch although functionally it makes no difference.
Leave the earth as it is, in the bit of terminal block. It doesnt connect to the Digistat itself.

 

[ark sez]

Thanks It's all installed now, nice to have heating back up and running!