The service techs, Dalton Turner and Christian Ramirez arrived on time. They looked at the situation and made suggestions for the most efficient solution, then got to work. They were finished in no time, cleaned up and hauled off the none-functioning parts. I highly recommend both the techs and Double L Plumbing. Thanks for the improved delivery speed of hot water from the tankless hot water heater. No more gallons of wasted water.