E127 High

Navien E127 Fault Code

The Navien E127 fault code means: your boiler's air pressure sensor is failing to communicate properly, which means the safety system is preventing the burner from lighting to ensure the unit operates safely.. It appears on 3 Navien models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: APS error (open, short, initial value or no response)
Typical repair cost £150-250 (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 E127 fault code

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

Source

Navien E127 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 7 July 2026