My Navien tankless water heater hadn't worked well for 4 months during this Covid-19 pandemic. We didn't ask the plumer to come for troubleshooting due to safety concerns of both parties untill recently Ontario entered into Phase-III economy reopening. We thought it would be good timing to ask a plumer to do inspection in house. We called Navien technical centre at US, and they recomended John with his his contact phone number. I called John. I was supprised that he promised to visit my house for inspection 2nd day. He came to my house and had inspection, found problems and fixed it. Thanks John.