Hi
have a Y plan heating system with honeywell st9400c controller and a wired honeywell thermostat in hallway .
I have worked out which wire on st9400c goes to which nest heat link terminal.
What I am not sure is how to get 12v power required for nest thermostat . I don't have a direct cable between thermostat and heat link. Also based on st9400c photo attached in don't have any spare cables between controller and main junction box.
Help please..
have a Y plan heating system with honeywell st9400c controller and a wired honeywell thermostat in hallway .
I have worked out which wire on st9400c goes to which nest heat link terminal.
What I am not sure is how to get 12v power required for nest thermostat . I don't have a direct cable between thermostat and heat link. Also based on st9400c photo attached in don't have any spare cables between controller and main junction box.
Help please..