I have a five year old Carrier 38TXA (puron).
I have it checked once a year, and it just passed about a month ago.
One thing I noticed this week is that when it starts up, I hear the fan go on, and then about 5 seconds later I hear a different noise that goes for about 2 seconds. It sounds like something is engaging or starting up with the fan (some extra drain on the system or motor).
Question: Is this normal? If not, is there something I should have checked?