Arrived on site. Performed factory authorized warranty change out of Navion 240A2 tankless water heater. Removed existing unit and installed direct replacement. Converted to new unit to propane. Set domestic hot recirc. programming to “always on” and internal valve to “external”. Purged air from lines. Tested water at nearest and farthest fixtures. Note: Hot wait time on furthest fixture was four seconds for a warm water and eight seconds for hot water. Bringing old unit and water test sample back to shop as requested by management. Thank you for choosing CPI Plumbing and Heating inc