How much does it cost to fix Navien error code E13?

Typical repair cost for the Navien E13 fault is £150-250 including labour.

E13 High

Navien E13 Fault Code

Q: What does the Navien E13 fault code mean?

Your boiler is struggling to detect the movement of water, which means it will prevent your hot water or heating from starting to protect the system from overheating.

The Navien E13 fault code means: your boiler is struggling to detect the movement of water, which means it will prevent your hot water or heating from starting to protect the system from overheating.. It appears on 6 Navien models in our database.

Technical description: Flow switch error

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 E13 fault code

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

NCB Repair: £150-250
NCB 28 HE Repair: £150-250
NCB 35 HE Repair: £150-250
NCB 40 HE Repair: £150-250
NCB H Repair: £150-250
NHB 29 Repair: £150-250

Source

Navien E13 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