What terminals do I use when changing an Isomac thermostat for an Iimit thermostat?

The Isomac thermostat uses terminals P and terminals 1.
The Limit thermostat uses terminals C and terminals 1.

Isomac thermostat
Limit thermostat

 

Note: There is no polarity on a thermostat therefore it doesn't matter which wire goes to which terminal as long as it is the correct two terminals.