Heating tune up in Suwanee, Georgia. Three systems. Changed filters. Tested mechanical and electrical components. Found upstairs system with dirty blower wheel. Recommend blower wheel pull and clean. Found upstairs gas line not up to code, it does not have a drip leg installed. Recommend installing drip leg on upstairs gas line to bring it up to code. Recommend installing overflow protection switches for downstairs and basement systems. Found basement main electrical switch with electrical pitting present, recommend repair. Systems are heating at this time.