How much does it cost to fix Navien error code TEC?

Typical repair cost for the Navien TEC fault is £90-140 including labour.

TEC Low

Navien TEC Fault Code

Q: What does the Navien TEC fault code mean?

Your boiler has reached its internal timer for a routine service and is simply reminding you that it is time for a professional maintenance check.

The Navien TEC fault code means: your boiler has reached its internal timer for a routine service and is simply reminding you that it is time for a professional maintenance check.. It appears on 6 Navien models in our database.

Technical description: Maintenance alarm. Generated when the power-on duration in days is greater than the value set at “W.Maintenance time”.

Typical repair cost £90-140 (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 TEC fault code

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

Source

Navien TEC 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