Yes, that is correct and by design. The thermostat enforces a safe operating range to prevent coil freezing and system damage.
The acceptable temperature ranges are fixed:
- Cool Mode: 50 °F to 99 °F (10.0 °C to 37.0 °C). You cannot set it lower than 50°F.
- Heat Mode: 40 °F to 90 °F (4.5 °C to 32.0 °C). You cannot set it higher than 90°F.
If you need a space colder than 50°F, this thermostat is not designed for that application, such as a wine cellar or commercial refrigeration. The limits are hardware-enforced for residential HVAC protection.
Verify you are in Cool mode. Press Menu > System Mode and select Cool. The setpoint will then be constrained to the 50-99°F range.