Completed tune-up on 7 York gas furnaces at commercial property in Shreveport. Scope included: combustion analysis with digital manometer (all units between 82-84% efficient), heat exchanger integrity check using camera scope, blower motor amp draw measurement, and flame signal verification. Found one unit with partial blockage in flue vent—cleared obstruction and verified proper draft. Replaced worn inducer motor bearings on two units to prevent midseason failure. All systems now operating within manufacturer specifications for the heating season.