Upon arrival zone system was on in cool, asked homeowner for air filters to replace and for small container of vinegar. Homeowner brought up concern about low airflow in primary bath, let him know I would take a look in attic at ducting. Dropped temperature on thermostat to keep unit operational during tune up Checked deltas on system and unit had a 18° delta Replaced old filter with new provided filter Checked blower motor and it is still in good condition Checked evaporator coil and it is clean and in good condition I poured some vinegar down the drain line and chased it with two gallons of water and had no back ups Lastly I checked electrical connections and condition of zone control board I then checked attic access to inspect ducting and found small 4" duct that splits into two for primary bath and closet causing low airflow in both rooms. Moved to outdoor condenser unit First I inspected disconnect box and it is in good condition, went ahead and flipped it to kill high vo