Hvac tune up in Buford, Georgia. Three systems. Tested mechanical and electrical components. Found upstairs furnace with weak flame safety sensor. Found upstairs system with only one form of water protection. Found upstairs system with rusty, corroded evaporater coil likely to leak refrigerant. Upstairs static pressure is a little high on supply side, recommend changing registers out with high flow registers to reduce static. Found master bedroom system with weak flame safety sensor. Master bedroom system has a rusted, corroded evaporater coil that is likely to leak. Found main system with weak flame safety sensor. Found main system with rusty, corroded evaporater coil likely to leak refrigerant. Found main system with weak blower capacitor (5uf). Due to age and condition of systems, recommend upgrading systems to more reliable and more efficient systems. Systems are heating at this time.