User's Manual

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Troubleshooting
Troubleshooting
Display is blank
• Check the circuit breaker and reset it if necessary.
• Make sure the heating and cooling system’s power switch is on.
• Make sure the furnace door is closed securely.
• If the thermostat is battery powered, make sure that fresh AA alkaline
batteries are correctly installed.
Temperature settings do not change
Make sure heating and cooling temperatures are set to acceptable ranges:
• Heat: 40° to 90°F (4° to 32°C).
• Cool: 50° to 99°F (10° to 37°C).
Heating system does not respond (
appears on screen)
• Check for 24VAC at the equipment on the secondary side of the transformer
between power and common. If voltage is not present, check the heating
equipment to find the cause of the problem.
• Check for 24VAC between the heat terminal (W) and the transformer
common. If 24VAC is present, the thermostat is functional. Check the heating
equipment to find the cause of the problem.
• Check for loose or broken wires between the thermostat and the heating
equipment.
Cooling system does not respond (
appears on screen)
• Check for 24VAC at the equipment on the secondary side of the transformer
between power and common. If voltage is not present, check the cooling
equipment to find the cause of the problem.
• Check for 24VAC between the cooling terminal (Y) and the transformer
common. If 24VAC is present, the thermostat is functional. Check the cooling
system to find the cause of the problem.
• Check for loose or broken wires between the thermostat and the cooling
equipment.
Fan does not turn on in a call for heat
• Check System Setting 06 (Fan Control) to make sure the fan control is
properly set to match the type of system (see page 22).
Heat pump issues cool air in heat mode or warm air in cool mode
• Check System Setting 01 (O/B Operation) to make sure the reversing valve
operation matches the heat pump.
Heat/Cool both on at the same time
• Check the Equipment Type selection switch to make sure it is set to match the
installed heating/cooling equipment (see page 21).
• Make sure the heating and cooling wires are not shorted together.