BoilerFaultCodes
Navien Boiler Fault Codes
357 fault codes across 9 Navien boiler models — explained in plain English.
Korean manufacturer known for high-efficiency condensing combi boilers.
Just want the most common Navien problems?
The top 8 faults across the whole Navien range — causes, DIY checks, repair costs.
High-severity Navien fault codes
E351 762 E762 E001 E003
Your boiler has been trying to refill its internal water supply for too long but has failed to reach the required level.
NCB-28LDWE
Your boiler has detected that the flue pipe responsible for safely venting exhaust gases outside has become loose or disconnected.
NCB-28LDWE
Your boiler is struggling to detect the exhaust vent, likely because the flue pipe is not fitted securely or is the wrong size for your home.
NCB-28LDWE
Your boiler has detected that the water temperature inside is getting dangerously high and has shut itself down to prevent damage or overheating.
NCB-28LDWE
Your boiler has failed to light the flame needed to heat your water and home.
NCB-28LDWE
All models
9 Navien boiler models
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