What should I do if my heating or cooling system is not responding to the thermostat?

For heating issues, press the Mode button to set the system to Heat and ensure the desired temperature is set higher than the current indoor temperature. For cooling, set the system to Cool and ensure the desired temperature is lower than the indoor temperature. Check and reset the circuit breaker if necessary, verify the heating and cooling system power switch is on, ensure the furnace door is closed securely, and wait 5 minutes for the system to respond. If the problem continues, contact a heating and cooling professional.