Thanks for advice. Couldn't find a model number on the old Landis & Gyr stat.
However was advised to swap 3 wire Drayton model for a 2 wire.
Instructions pretty clear and have fitted this one successfully. Red live, black as call signal. Thermostat & heating seem to be running OK. Thanks again.
Hello. I am replacing an old Landis & Gyr room thermostat with a Drayton RTS1. The current wiring on the old stat is red, black and blue. Red is live, The blue is wired into the earth position, so I presume that in this set up the black wire is neutral.
Our new Drayton is double insulated so...