Performed a Homecare maintenance inspection on both HVAC systems in the home (upstairs and main floor). The customer informed us that both heat exchangers have recently been replaced by their home warranty company. Tested heating and cooling from the thermostats. Measured the refrigerant pressures and electrical component readings. Inspected the safety and cleanliness of the system. Checked and replaced the 1” air filters. Treated the drain lines with enzymes. Reported findings to the customer. Customer approved to perform repairs on the main floor system flue vent. Picked up material from Apex Supply Marietta. Disposed of the single wall flue vent and discovered that the roof connection was not fully sealed, only connected with silver tape. Connected the double wall flue vent and ensured the flue pipe is connected to the furnace. Highly recommended that the customer calls out a roofer to take a look at the roof connection.