.................................................................................................................................................................... 24 11.1. LOW EMISSION fire lighting.......................................................................................................................................................................... 25 12. NORMAL OPERATION ................................................................................................................................................ 26 13. OPERATION DURING TRANSITION PERIODS ............................................................................................................ 26 14. MAINTENANCE AND CARE ......................................................................................................................................... 26 14.1. CLEANING OF THE FLUE ............................................................................................................................................................................ 26 14.2. CLEANING OF THE GLASS ......................................................................................................................................................................... 26 14.3. CLEANING OF THE ASH .............................................................................................................................................................................. 27 15. SUMMER TIME ............................................................................................................................................................ 27 16. CALCULATION OF THE THERMAL POWER. ......................................................................................................