No Power is the most common correctable issue.

Check the breaker in the breaker box.  Reset the breaker even if it appears to be in the on position.  If this fixes the issue, you are all set.  While it is common for a breaker to trip without any hidden issues,  if it trips repeatedly, call us, there is something causing this.  

 

Check the Batteries in the thermostat.  They could be low casuing power issues. 

 

Check your disconnect switches.  If your furnace is in the garage you can sometimes hit the disconnect switch without knowing it, there is also a disconnect outside at the Air Conditioner Disconnect Box. 

 

Check your Filter to make sure it is properly in place.

Some newer models will shut down if the fliter is not in place correctly.  The problem is resolved by securing the filter.