Digital Thermostat fitting

[Robbox]

My Honeywell thermostat is mechanical variety, 6360, when I open it up, there are four wires connected, one being earth.
I'd like to swap out for the Honeywell DT90, digital thermostat. It only requires a live and neutral.
Can I ignore the third wire in the old thermostat?

 

[Ihavenojob]

It will not need the neutral, just live(line) and load (calling for heat). Safely isolate the neutral. Looks like 1 & 3 from the old stat will be needed.

 

[ianmcd]

you only need a neutral in a thermostat as a heat anticipator, a digital thermostat will not use a neutral

Honeywell DT90, digital thermostat. It only requires a live and neutral.

Wrong it doesnt use a neutral, it has a live and switched live, no neutral , no earth