ACL RTS-1 to Horstmann HRT4-B thermostat wiring advice?

[aquila]

Hi,

I have an existing (ACL Drayton) Room Thermostat RTS-1 and would like to know if it is at all possible to replace it with a Horstmann HRT4-B without requiring additional wiring?

If it is possible what are the wiring terminal connections I need to make?

Grateful thanks in advance

View media item 48942
Existing RTS1 wiring: N=Blue, L=Red, 3=Yellow, Earth connected to metal wall box.

View media item 48941

 

[denso13]

L is 1 on new stat, 3 is 4 on new stat. Put the old stat neutral in a piece of terminal block as it won't be connected to the new stat.

 

[aquila]

L is 1 on new stat, 3 is 4 on new stat. Put the old stat neutral in a piece of terminal block as it won't be connected to the new stat.

Many thanks for that