E480 High

Navien E480 Fault Code

The Navien E480 fault code means: your boiler's hot water sensor has stopped sending a signal, which means it cannot tell how hot the water is and has stopped heating it to prevent overheating.. It appears on 7 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: DHW Tank 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.

Find a Gas Safe engineer

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

Gas Safe Register →

Navien models that show the E480 fault code

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

Source

Navien E480 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