1. Wear and tear
Normal wear and tear can cause airflow problems, heat control-related problems or even overheating.
2. The furnace is too noisy
Rumbling, squeaking and rattling aren’t normal. The sounds may indicate a mechanical problem, airflow reductions or a clogged burner.
3. The blower continuously runs
Blower issues may indicate a problem with the limit switch, which a professional may need to replace.
4. The furnace doesn’t heat at all
A furnace that doesn’t perform its main task may have problems with the thermostat setting, power, gas or the pilot light.
5. Frequent cycling
Cycling between the “On” and “Off” modes may indicate a clogged filter, improper airflow or a bad thermostat setting.