Humidty reading remains at 84%

I have a Danby Silhouette dehumidifier model DDR583R. The humidity is reading 84% and has remained around that level for months. I purchased a simliar unit (Danby DDR5588RHE) and it is showing a humidity reading of 69% (the units are beside each other). Both units are set for 50% and it sounds like my original unit's compressor is working. I think that the humidistat is providing a false reading. Your guidance is appreciated.

Jeff