Furnace tune up in Dacula, Georgia. Two systems. Changed filters. Tested mechanical and electrical components and found no issues. Upstairs system’s water safety is code compliant but has no backup. Recommend installing overflow protection switch to help protect furnace from potential water damage and to serve as a backup to primary water safety switch. Neither system has surge protection installed. Recommend installing surge protection to protect equipment from power surges. Systems are heat8ng at this time. Customer used $50 gift card