Performed preventative maintenance on furnace. Inspected blower assembly, motor, electrical components, burners, flame sensor, ignitor, gas valve, inducer motor and overall condition of equipment. Customer stated that he’s noticed water leaking again along the exhaust pipe of the furnace. We put some caulking around it last time. I took caulking off and was able to locate where the leak was coming from. Pipe needed to be sealed at the connector. I was able to lift piping up and put pvc glue on connections and put them back together. Cleaned flame sensor and dust off the burners and components. Checked thermostat operation, wiring, amps, temperatures and gas pressure. Evaporator coil needed to be cleaned. Customer approved a coil cleaning in place. I cleaned the evaporator coil with cleaner and wire brushes. Showed before and after photos to customer. System is heating properly.