Since HA using Lovelace as frontend, Climate component appears problem which is the component often doesn't get feedback from HVAC stat. But sometime after reboot, it will work for a while. The climate component is zhonghong. It used work when frontend is not Lovelace, it appears a common problem which I also found in Chinese HA forum.
Hey there @wangyt123ng please do not delete the issue template. All requested information is important to help out with this issue. You can find the template again here: https://github.com/home-assistant/home-assistant-polymer/issues/new?labels=bug&template=BUG_REPORT.md

This is the screenshot of HVAC component while it's not working. When it's working it will display current temperature.
Also I can open the AC but couldn't turning it off when it's not working, and no log error reported.
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Hey there @wangyt123ng please do not delete the issue template. All requested information is important to help out with this issue. You can find the template again here: https://github.com/home-assistant/home-assistant-polymer/issues/new?labels=bug&template=BUG_REPORT.md