2ContentsContents ........................................................................................................ 2Owner's GuideImportant Safety Information ....................................................................... 3General PartsMain Unit .................................................................................................... 7Remote Controller .................................................................................... 8Initial Operation ........................................................................................... 10How to Use (Using the remote controller)Muting the Remote Controller ................................................................. 11Setting and Using the Water Heater ........................................................ 12Flow Meter Alarm ...................................................................................... 14How to Use (Not using the remote controller)Setting and Using the Water Heater ........................................................ 16Preventing Damage from Freezing ............................................................ 17Regular Maintenance ................................................................................... 19Troubleshooting .......................................................................................... 21Follow-up Service ........................................................................................ 25Specifications .............................................................................................. 26External outfitting ........................................................................................ 27Combustion unit and gas route .................................................................. 29Hot-water feed route for N-069M only ........................................................ 31Hot-water feed route for N-063S only ........................................................ 32Electronic control unit ................................................................................. 34Electronic control unit, Remote controller and Attached set .................. 35Installation Manual ...................................................................................... 361. Included Accessories ............................................................................ 372. Optional Accessories ............................................................................ 373. Quick Connect Multi System Installaion ............................................. 384. Before Installation ................................................................................. 395. Choosing Installation Site .................................................................... 396. Installation Clearances ......................................................................... 417. Installation .............................................................................................. 448. Vent Pipe Installation (Indoor Installation Only) ................................. 459. Gas Piping .............................................................................................. 4810. Water Piping ........................................................................................... 5011. Plumbing Applications .......................................................................... 5112. Electrical Wiring .................................................................................... 5213. Maintenance ........................................................................................... 5614. Trial Operation ....................................................................................... 5615. Dimensions ............................................................................................ 58Remote Controller Installation Guide ....................................................... 61