Honeywell RTH9580 Wi-Fi Troubleshooting Manual

Display is blank

• Check circuit breaker and reset if necessary.
• Make sure power switch at heating and cooling system is on.
• Make sure furnace door is closed securely.
• Make sure C wire is connected.

Cannot change system setting to Cool

• Check that System Setup screen "Your thermostat controls" or "Your system type" is set to match your heating and cooling equipment.

Fan does not turn on when heat is required

• Check that System Setup screen "Your fan control" is set to match your heating equipment.

"Wait" appears on the screen

• Compressor protection feature is engaged. Wait 5 minutes for the system to restart safely, without damage to the compressor.

Heat pump issues cool air in heat mode, or warm air in cool mode

• Check your setting for System Setup screen "Type of changeover valve" to make sure it is properly configured for your system.

Heating or cooling system does not respond

• Touch SYSTEM to set system to Heat. Make sure the temperature is set higher than the Inside temperature.
• Touch SYSTEM to set system to Cool. Make sure the temperature is set lower than the Inside temperature.
• Check circuit breaker and reset if necessary.
• Make sure power switch at heating and cooling system is on.
• Make sure furnace door is closed securely.
• If "Wait" is displayed, the compressor protection timer is on. Wait 5 minutes for the system to restart safely, without damaging the compressor.

Heating system is running in cool mode

• Check that System Setup screen "Your thermostat controls" or "Your system type" is set to match your heating and cooling equipment (see "System Setup Options (MENU > System Setup)".