Homeowner has a small drip coming from the exhaust for the tankless. The drip is on a 2” pressure 90°. I cut out and removed the failed 90°. Installed a new 2” pressure 90° and approximately 6” of 2” pressure PVC, with a pressure coupling. Connected to existing exhaust system. The exhaust has a significant bow to it, if another leak forms, at that point, it would be time to cut out and remove the bowed section of exhaust. I informed the homeowner of this issue. Water pressure in house is 55 PSI The water heater is a Navien NPE-240A2 that is 2 years old