Don't know too much about these, so better to let some one else reply.
We buy a service contract with a company and they deal with all of the maintenance.
The guy who does it has been servicing our unit for over a decade. He is the one who told us what the issue was.
These guys have to face customer pushback and increase workload due to dumb ceo decisions.
Anyway, what these guys do is clean the filter sometimes as needed and replace it maybe once a year. So they dont always replace it.
Dunno for sure as i don't usually have to deal with this.
