Why is my heating or cooling system not responding to the thermostat?

First, confirm the SYSTEM button is set to the correct mode (Heat or Cool) and that the set temperature is higher than room temperature for heating, or lower for cooling. Also check that the circuit breaker is not tripped, the power switch at the system is on, and the furnace door is securely closed — then wait up to 5 minutes for the system to respond. (Page 12)