A. Check for a dirty filter, is the power switch on, is the circuit breaker tripped, is the thermostat set to heat or cool and the proper temperature?

A. Yes, as your filter gets too dirty its ability to capture and hold particles decreases and more dust and dirt can come through the filter. It’s important to use a good quality filter, typically in the 8-12 MERV range. Below MERV 8 it does not capture enough particles and above MERV 12 it is too restrictive to air flow.