How much does it cost to fix Navien error code E127?

Typical repair cost for the Navien E127 fault is £150-250 including labour.

E127 High

Navien E127 Fault Code

Q: What does the Navien E127 fault code mean?

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.

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 8 Navien models in our database.

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.

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

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 27 April 2026