Customer had a leaking condensate drain on their tankless. After running through diagnostics on the unit we found some deficiencies. The gas line was undersized, condensation drain had brass fittings, the heat exchanger was extremely filled with soot and other debris, and the unit was 13 years old with no maintenance history. We recommended replacing and gave options. Customer decided to have us install a new 50 gal power vent water heater. We installed with all code upgrades and new gas fittings. Restored water and tested for leaks and proper function.