Tankless Water Heater Error Codes
41 tankless water heater codes across 2 brands. Find your code, see what it means, and how to fix it.
Navien Tankless Water Heater Codes
E003 E003 — Ignition Failure E003C E003C — Cascade Ignition Failure E012 E012 — False Flame / Flame Loss E016 E016 — Overheat / High-Limit Trip E027 E027 — Gas Type Setting Error E030 E030 — Fan / Combustion Blower Fault E046 E046 — Mixing Valve Error E109 E109 — Fan Motor Abnormal Operation E110 E110 — Exhaust Blockage / APS Fault E193 E193 — Condensate Drain Blockage E351 E351 — Water Flow Sensor Fault E406 E406 — Heat Exchanger Scale / Lime Buildup E432 E432 — Outlet Thermistor Fault E438 E438 — Inlet Thermistor Fault E515 E515 — PCB / Control Board Abnormal E594 E594 — Gas Valve / Modulation Fault E615 E615 — Remote Controller Communication Error E760 E760 — Water Leak Detected E777 E777 — Dip Switch Setting Error
Rinnai Tankless Water Heater Codes
02 02 — Power Interruption / Memory Loss 03 03 — Loss of Communication / EZConnect Issue 10 10 — Air Supply or Exhaust Blockage 11 11 — No Ignition 12 12 — Flame Failure 14 14 — Thermal Fuse / Overheat Cutoff 16 16 — Outgoing Water Over-Temperature 25 25 — Condensate Drain Blocked (Condensing Models) 31 31 — Burner Sensor (Combustion Offset) Fault 32 32 — Outgoing Water Thermistor Fault 33 33 — Heat Exchanger Thermistor Fault 34 34 — Combustion Air Temperature Sensor Fault 51 51 — Gas Solenoid Valve Fault 52 52 — Modulating Solenoid Valve Signal Abnormal 61 61 — Combustion Fan Motor Fault 65 65 — Water Flow Control Valve Fault 70 70 — PCB / Control Board Fault 71 71 — Gas Solenoid Drive Circuit Fault 72 72 — Flame Sensor Fault 90 90 — Combustion Abnormality 99 99 — Exhaust Blockage / Fan Issue LC LC — Scale Buildup / Descale Reminder