Issue
The minimum activation value for a terminal load exception mode is 14.0 and minimum reset value is 32.0.
Environment
Zbuilder 5.1.5-5.1.6
Xenta 121-FC
Xenta 121-HP
Cause
In Zbuilder 5.1.5 the option to use an exception mode based on terminal mode exists (Restricted to Exception mode 7 and 8). The units for the activation and reset values are treated as temperatures.
If Zbuilder is displaying values in US units then it will restrict your minimum values as 14.0 F activation, 32.0 F reset value, and the reset value must be below the activation value if using the above condition.
The unit is actually using a Celsius value to store the settings and this is being converted to F.
Resolution
Change the configure to display values in SI and then set the activation and reset values as a 0-100% value.
Then you can change the units back to US and have it convert the value automatically.
Warning: Note that even though terminal load is -100% to 100% the exception mode will ignore the sign of the terminal load. Use the "Controller is in cooling mode" and "Controller is in heating mode" check boxes to restrict the behavior to a positive or negative terminal load.