The heating and/or cooling outputs do not work when the TAC Xenta 121-HP is configured as a slave controller.
TAC Xenta 121-HP versions up to 1.25
If the device is configured as a slave, heating and cooling is dependent upon the isolation valve value. If there is no isolation valve configured, the heating and cooling outputs will be blocked.
The isolation valve needs to be configured regardless of whether it exists or not in order to make the heating and cooling outputs work.