Medium
E046 on Navien NCB500 NCB500-15K System

Your boiler has detected a potential issue with its safety temperature switch, which ensures the water does not get dangerously hot.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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.

What the manual says

Manufacturer manual

Unable to detect high water temperature conditions if the switch malfunctions

From this model's manual
Verified against the Navien/Navien Ncb500 System Service Manual En 250331 Pdf installation & service manual.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

E043View →E045View →E047View →

All 52 fault codes on the NCB500 NCB500-15K System

Seeing a different code? Every code this model can display, in one place.

001003004012016030031046047109205218302352353515517593594615740782E001E003E004E012E016E030E031E047E109E110E205E218E291E302E351E352E353E480E515E517E593E594E598E615E740E782E783E787E788

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