What should I do if my heating or cooling system does not respond to the thermostat?

First, press the Mode button to confirm the correct mode (Heat or Cool) is selected and verify the setpoint is above or below the current room temperature accordingly. Also check that the circuit breaker is not tripped, the system power switch is on, the furnace door is securely closed, and then wait up to 5 minutes for the system to respond. (Page 13)