Navien Boiler Error Codes

A plain-English reference to 23 common Navien fault codes — what each means, what causes it, and when to call a licensed BC gas technician.

Navien is the most common condensing combi brand in Greater Vancouver homes. Its NCB, NHB and NFB boilers display a numeric "E" code on the front panel when a safety circuit trips. Below is a plain-English reference to the most common Navien fault codes — what each means, what causes it, and why ignition, flame, gas and venting faults are work for a licensed BC gas technician rather than a DIY reset.

Smell gas? Leave the building immediately and call 911 or FortisBC at 1-800-663-9911 from outside. Never bypass a safety lockout or attempt gas work yourself — in BC it must be done by a licensed gas fitter.

Ignition fault

Navien E003Ignition Failure

Flame failure

Navien E004False Flame Detected Navien E012Loss of Flame During Operation

Over-temperature / high-limit

Navien E016Overheating / Abnormal High Temperature Navien E043Overheat Protection Device Tripped

Air-pressure / venting fault

Navien E027Air-Pressure Sensor (APS) Fault Navien E030Flue / Exhaust Over-Temperature Navien E047Exhaust Connection / APS Fault Navien E060Air-Pressure Sensor Abnormal Navien E110Exhaust Blockage / Air-Pressure Fault

System water-pressure fault

Navien E032Water-Leak / Abnormal Detection

Communication fault

Navien E034PCB Communication Error Navien E351Cascade Communication Error Navien E740Comms / Accessory Fault Navien E760NaviLink / Wi-Fi Communication Fault

Water-flow / circulation fault

Navien E041Flow Sensor / Water-Adjustment Fault Navien E594Flow-Sensor Signal Fault

Combustion-fan fault

Navien E109Combustion-Fan Fault

Temperature-sensor fault

Navien E406Inlet (CH Return) Thermistor Fault Navien E421DHW / Outlet Thermistor Fault Navien E438Mixing / Sensor Configuration Fault

Control-board (PCB) fault

Navien E515Main Control (MICOM) Abnormal

Electrical / power fault

Navien E527Electrical / Board Output Fault

Navien error codes — FAQ

Why is my Navien boiler showing an error code?

Navien boilers display a fault code when a safety circuit detects a problem — for example with ignition, flame, water flow, temperature or venting. The code points to the affected system. The boiler shuts down to protect itself; a licensed technician then diagnoses the true root cause before repair.

Can I just reset my Navien boiler?

A single reset after a one-off event is usually fine, but repeated resets without fixing the cause can be unsafe — especially for ignition, gas and venting faults — and can cause further damage. If the code returns, switch the boiler off and call GasBoilers.ca at 604-359-1081.

Do you repair all Navien boiler models in Greater Vancouver?

Yes. Our Red Seal–certified, gas-licensed technicians service Navien NCB-E, NCB-H, NHB, NFB and NPE-A2 series across Vancouver, Burnaby, Surrey, Richmond, the Tri-Cities and the rest of Greater Vancouver. Same-day appointments are often available.

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Get your Navien boiler back up and running

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