Why does my 9000 series thermostat show "sensor error”?
Some of the 9000 series thermostats (RTH9585WF, THX9421R, TH9320WF) are displaying 'sensor error' when placed in low humidity installation locations. If the thermostat spent time in a low humidity environment, such as a cold car or van, warehouse, or the installation location has lower than 10% humidity, the 9000 series can show 'sensor failure' until the ambient humidity rises. We understand this can be alarming to our customers, as the error specifically states to replace the thermostat. Please dismiss the alert and allow 24-48 hours for your thermostat sensor to "normalize" and read the correct humidity in your space.