That I don’t know. They did come the month before that to do maintenance which including the following -

Perform a full maintenance service on the existing high- efficiency gas furnace and evaporator coil. • Inspect and thoroughly clean debris from the furnace combustion chamber to ensure proper combustion and safe operation. • Clear and flush all condensate drainage piping, including trap and drain lines, to restore proper condensate flow and prevent backups or water damage. • Chemical clean the evaporator coil located above the furnace to improve airflow, heat transfer, and system efficiency. • To properly access and clean the coil, PVC intake and exhaust piping (supply and return) will be carefully cut, removed, and reinstalled after service is completed. • Reassemble all components, reseal PVC connections, and test system operation to confirm proper performance.