How much does it cost to fix Navien error code E432?

Typical repair cost for the Navien E432 fault is £150-250 including labour.

E432 High

Navien E432 Fault Code

Q: What does the Navien E432 fault code mean?

Your boiler is struggling to detect when you turn on the hot tap, meaning it isn't heating water for your taps or shower as it should.

The Navien E432 fault code means: your boiler is struggling to detect when you turn on the hot tap, meaning it isn't heating water for your taps or shower as it should.. It appears on 6 Navien models in our database.

Technical description: DHW Flow Sensor 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.

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Navien models that show the E432 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 E432 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