Customer call about code 11 on rinnai tankless water heater I clean the flame rod and fan but still show code 11 we need to come back flush the tank tested and see if this happens again maybe need call tech support do we can find out the issue. I can’t call tech support 04/18/24 lee Called out today to perform the annual tankless flush Flushed heater for 45 mins to insure it was cleaned Drained Off 4 gal of clean water for the unit Filled unit back up and tested Everything is working properly at this time Location Garage Rinnai tankless Model numbers Rl94i Serial number is Reu-vc2837ffud-us Date on unit is 2011 Natural gas Job complete Payment is pics