Fault 15 / 30 Low

Worcester Bosch Fault 15 / 30 Fault Code

Also written as FAULT1530 — same fault.

The Worcester Bosch Fault 15 / 30 fault code means: your boiler has lost communication with its outdoor weather sensor, meaning it cannot automatically adjust your heating based on the temperature outside.. It appears on 1 Worcester Bosch model in our database.

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description: Outside temperature sensor not connected: Outside temperature sensor not recognised.

What causes the Worcester Bosch Fault 15 / 30 fault?

This fault occurs when the boiler's main control board can no longer detect a signal from the sensor located on the outside of your home. The most common reasons are a break in the wiring connecting the sensor to the boiler, or the external sensor itself failing due to exposure to the elements.

This fault is often noticed during the transition into autumn or winter when the boiler first attempts to use external temperature data to regulate the heating.

Typical repair cost £90-180 (including labour)

Engineer required

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

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Worcester Bosch models that show the Fault 15 / 30 fault code

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

Source

Worcester Bosch Fault 15 / 30 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026