We had a tankless water heater installed. It was not installed properly and we were very disappointed. A technician came and programmed the computer for the FIRST time, which improved the wait time, but it was still 2 minutes every time we turned it on, sometimes up to 7 minutes. We complained again and they sent the same technician. He didn't even look at the heater. We just put up with that for a while. When AAA called to schedule a maintenance cleaning we said YES . A different technician came and checked out the heater. It had a filter that needed cleaning severely. He cleaned it in our kitchen sink and then flushed it with 4 gallons of vinegar. After he left we realized that the heater was working the way that we had expected it to when we had it installed. I called AAA and reported that. We Are much happier with it now.