How much does it cost to fix Navien error code Q-Error?

Typical repair cost for the Navien Q-Error fault is £100-£200 including labour.

Q-Error High

Navien Q-Error Fault Code

Q: What does the Navien Q-Error fault code mean?

Your boiler's computer does not recognise which specific version of the appliance is installed, preventing it from functioning correctly.

Also written as QERROR — same fault.

The Navien Q-Error fault code means: your boiler's computer does not recognise which specific version of the appliance is installed, preventing it from functioning correctly.. It appears on 6 Navien models in our database.

Technical description: Model or capacity setting error

Typical repair cost £100-£200 (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 Q-Error fault code

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

Source

Navien Q-Error 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