E441 Medium

Navien E441 Fault Code

The Navien E441 fault code means: your boiler is having trouble sensing the temperature of your hot water supply, which will likely prevent it from heating your water correctly.. It appears on 3 Navien models in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: Domestic hot 2: thermistor open or short circuit
Typical repair cost £120-220 (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 E441 fault code

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

Source

Navien E441 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