Arrived on site for heating maintenance. Homeowner stated all was well with regards to normal unit operation. However, one kitchen vent was starting to show signs of bacterial growth and another upstairs was showing some signs of water stains around the return at the top of the stairs. I thoroughly inspected around the return grill and found no water only slight signs of water stains on some of the rafters and a box in the attic. Flushed drain line to ensure there were no leaks and I did not find any this leads me to believe the water was not coming from the hvac system and likely coming from the roof. As for the other kitchen vent it was found to not be sealed from attic air and the duct was larger (9”)and a shorter run than all of the other ducts coming off of the supply side of the unit. I sealed around the duct and used panduit straps to restrict the airflow for the time being. Also found closed vent in the kitchen. Opened this vent to reduce airflow to the kitchen vent. Discussed
