The thermostat has enforced temperature limits to prevent system damage. You are hitting the lower bound for Cool mode.
Check your current system mode:
- Cool Mode: The allowable range is 50 °F to 99 °F (10.0 °C to 37.0 °C). You cannot set it below 50°F.
- Heat Mode: The allowable range is 40 °F to 90 °F (4.5 °C to 32.0 °C). You cannot set it below 40°F.
To proceed:
- Press Menu > System Mode.
- Confirm which mode (Heat or Cool) is active.
- Set your desired temperature within the specified range for that mode.
If that didn't work: If you need a temperature outside these ranges (e.g., for vacation hold), you may need to switch to the opposite mode or use a specialized 'Away' setting via the app, which may have different parameters.