Equipment guide

Boiler error codes

Codes are manufacturer-specific. Choose the exact brand shown on your equipment.

E001
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E001 as heat exchanger overheat. This meaning is limited to the documented NCB-H condensing combi-boiler.

E003
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E003 as ignition failure. This meaning is limited to the documented NCB-H condensing combi-boiler.

E004
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E004 as false flame. This meaning is limited to the documented NCB-H condensing combi-boiler.

E012
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E012 as flame loss. This meaning is limited to the documented NCB-H condensing combi-boiler.

E016
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E016 as heat exchanger overheat. This meaning is limited to the documented NCB-H condensing combi-boiler.

E030
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E030 as exhaust overheat. This meaning is limited to the documented NCB-H condensing combi-boiler.

E031
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E031 as burner overheat. This meaning is limited to the documented NCB-H condensing combi-boiler.

E046
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E046 as heat exchanger thermistor error. This meaning is limited to the documented NCB-H condensing combi-boiler.

E047
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E047 as exhaust thermistor error. This meaning is limited to the documented NCB-H condensing combi-boiler.

E060
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E060 as abnormal dual venturi. This meaning is limited to the documented NCB-H condensing combi-boiler.

E109
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E109 as abnormal fan motor. This meaning is limited to the documented NCB-H condensing combi-boiler.

E110
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E110 as exhaust blockage. This meaning is limited to the documented NCB-H condensing combi-boiler.

E205
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E205 as heating supply temperature sensor error. This meaning is limited to the documented NCB-H condensing combi-boiler.

E218
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E218 as heating return temperature sensor error. This meaning is limited to the documented NCB-H condensing combi-boiler.

E278
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E278 as external supply sensor not detected. This meaning is limited to the documented NCB-H condensing combi-boiler.

E279
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E279 as external return sensor not detected. This meaning is limited to the documented NCB-H condensing combi-boiler.

E291
Navien

The official NFB-H Condensing Boilers Installation Manual identifies E291 as heating return temperature exceeds the heating supply temperature. This meaning is limited to the documented NFB-H condensing boiler.

E302
Navien

The official NFB-H Condensing Boilers Installation Manual identifies E302 as low water pressure. This meaning is limited to the documented NFB-H condensing boiler.

E351
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E351 as abnormal automatic feeder valve. This meaning is limited to the documented NCB-H condensing combi-boiler.

E352
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E352 as high water pressure. This meaning is limited to the documented NCB-H condensing combi-boiler.

E353
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E353 as water pressure sensor error. This meaning is limited to the documented NCB-H condensing combi-boiler.

E407
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E407 as domestic hot-water outlet sensor error. This meaning is limited to the documented NCB-H condensing combi-boiler.

E421
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E421 as domestic cold-water inlet sensor error. This meaning is limited to the documented NCB-H condensing combi-boiler.

E434
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E434 as abnormal water-adjustment valve. This meaning is limited to the documented NCB-H condensing combi-boiler.

E439
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E439 as no domestic water flow detected. This meaning is limited to the documented NCB-H condensing combi-boiler.

E441
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E441 as domestic hot-water outlet sensor 2 error. This meaning is limited to the documented NCB-H condensing combi-boiler.

E445
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E445 as abnormal mixing valve. This meaning is limited to the documented NCB-H condensing combi-boiler.

E480
Navien

The official NFB-H Condensing Boilers Installation Manual identifies E480 as domestic hot-water tank sensor not detected. This meaning is limited to the documented NFB-H condensing boiler.

E515
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E515 as abnormal pcb. This meaning is limited to the documented NCB-H condensing combi-boiler.

E517
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E517 as abnormal dip switch. This meaning is limited to the documented NCB-H condensing combi-boiler.

E594
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E594 as abnormal eeprom. This meaning is limited to the documented NCB-H condensing combi-boiler.

E615
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E615 as abnormal memory. This meaning is limited to the documented NCB-H condensing combi-boiler.

E736
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E736 as cascade communication error. This meaning is limited to the documented NCB-H condensing combi-boiler.

E740
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E740 as outdoor sensor not detected. This meaning is limited to the documented NCB-H condensing combi-boiler.

E761
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E761 as pump aquastat not detected. This meaning is limited to the documented NCB-H condensing combi-boiler.

E762
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E762 as vent pipe not fully inserted. This meaning is limited to the documented NCB-H condensing combi-boiler.

E773
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E773 as improper gas type detected. This meaning is limited to the documented NCB-H condensing combi-boiler.

E777
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E777 as low-water cutoff activated. This meaning is limited to the documented NCB-H condensing combi-boiler.

E782
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E782 as front-panel communication error. This meaning is limited to the documented NCB-H condensing combi-boiler.

E784
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E784 as zone-controller communication error. This meaning is limited to the documented NCB-H condensing combi-boiler.

E786
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E786 as improper front panel. This meaning is limited to the documented NCB-H condensing combi-boiler.

E788
Navien

The official NCB-H Condensing Combi-Boilers Installation and Operation Manual identifies E788 as incorrect gas-type setting. This meaning is limited to the documented NCB-H condensing combi-boiler.