Honeywell RTH8500 Operating Manual
![Honeywell RTH8500 Thermostat manual cover](/images/JDTtOsfDGlVecQgZyjzSxwnf/thumbs/thumb175x175.webp)
To program the schedule, press the 'Menu' button, select 'Schedule', and follow the prompts to set wake, leave, return, and sleep times for each day of the week.
Check that the thermostat is set to 'Heat' mode. Ensure that the set temperature is higher than the current room temperature. Also, verify the wiring connections and check the circuit breaker.
To lock the screen, go to 'Menu' > 'Preferences' > 'Screen Lock', and follow the instructions to set a lock code.
The low battery warning indicates that the thermostat's batteries are running low. Replace them with fresh AA alkaline batteries to ensure proper operation.
To reset the thermostat, press and hold the 'Menu' button for 5 seconds, select 'Reset', and confirm by selecting 'Yes'. Note that this will erase all custom settings.
The Honeywell RTH8500 does not have Wi-Fi capability. It is a programmable thermostat that requires manual scheduling adjustments.
To switch temperature units, press 'Menu', go to 'Preferences', and select 'C/F'. Choose your desired unit and press 'Save'.
Ensure that the screen is not locked. If it is not locked, try resetting the thermostat by removing the batteries and reinserting them. If the issue persists, contact Honeywell customer support.
The temperature swing can be adjusted in the 'Installer Setup' menu. Access it by pressing 'Menu', then 'Preferences', and look for the 'Temperature Swing' setting to adjust as needed.
Regular maintenance includes replacing the batteries annually or when low battery warnings appear, and cleaning the screen with a soft, lint-free cloth.