E110 Emergency

Navien E110 Fault Code

The Navien E110 fault code means: your boiler has detected that waste water cannot drain away properly or the flue is blocked, so it has safely shut itself down to prevent damage or dangerous gas buildup.. It appears on 7 Navien models in our database.

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

Technical description: Exhaust blockage (Condensate blockage)
Typical repair cost £120-250 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Navien models that show the E110 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Navien E110 fault code information on this page is sourced and cross-checked against the official Navien service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026