Thermostat wiring help

[Profdriver]

Hi just need some advice on wiring.

Ive put a picture of wiring behind my current thermostat and thinking of replacing it with a new wireless thermostat.

Can someone give me advice please on what wires go where in the new thermostat. (not purchased yet)

 

[45yearsagasman]

Not a great help not knowing your new stat, or much about your existing system. Programmer, motorised valves etc.
The neutral should be self explanatory
The L might be from your programmer
The 3 is either to a pump or possibly a motorised valve.
Not much help I know, but little to go on.

 

[Steelmasons]