My second thermostat is a manual, wired one. Now not working after extension kit installed

sundialSoft

I had installed one taco thermostat for our downstairs area while retaining a manual thermostat upstairs and the original programmer. This was working fine and the manual thermostat worked with the programmer set to run.

Having now installed an extension kit (to get hot water control) my manual thermostat does not seem to be working.

The hot water control and the Tado thermostat downstairs work properly.

Do I need to replace the manual thermostat or is there something else I can do?

thanks in advance

Ian