You will want to use the wire labeled "Y" in your schematic as the "C" wire for your thermostats.



Need help running and connecting a 'C' wire to my new thermostat
After

\def\MyText{\textbf{My Text}}
\let\MySaved\MyText


\MySaved and \MyText have the same \meaning. What I would like to have further down in the document is

% \MyText = \textbf{My Text}
\def\MyText{\textit{More Text}}
\let\MySaved{\MySaved \MyText}
% \MySaved = \textbf{My Text} \textit{More Text}


but obviously \let does not allow a group of tokens in the second argument.

Is there any way to append like this with the same specific (non-)expansion properties \let has?
