I live in Florida. I have an eight year old carrier heat pump (split system) that maintains adequate cooling temps at night (after senset when temps cool down to below 80) but cannot keep up during the hottest parts of the day: the compressor never shuts down and the temp remains above set during daytime but works normall at night. This started about two weeks ago.

The filters and coils are clean. All systems look and sound normal.

Does anyone know why. Thanks

Put a manifold gauge on it and check your pressures. There may be a slow leak...

How long have you lived in house? Has it been giving this prob. For a long time ? Forever? Or has it just started? Prob. Low on freon,, maybe thin walls and lacking insulation,maybe non-insulated windows,, I`m talking about especially the room where the thermostat is located,, is the tstat located on interer wall and not a outside wall,,