How much does it cost to fix Ravenheat error code 42E?

Typical repair cost for the Ravenheat 42E fault is £90-250 including labour.

42E High

Ravenheat 42E Fault Code

Q: What does the Ravenheat 42E fault code mean?

Your boiler has shut down because there is a confusing difference between the temperatures recorded at its internal sensors, often caused by poor water flow or a sensors reading incorrectly.

The Ravenheat 42E fault code means: your boiler has shut down because there is a confusing difference between the temperatures recorded at its internal sensors, often caused by poor water flow or a sensors reading incorrectly.. It appears on 7 Ravenheat models in our database.

Technical description: Different temperature error

What causes the Ravenheat 42E fault?

This fault occurs when the boiler's control system detects a significant conflict between the readings of the flow and return temperature sensors. The most common cause is poor water circulation through the heat exchanger, often due to a failing pump or debris in the system causing the water to overheat too quickly.

This issue often surfaces in autumn when the heating is turned on for the first time, as pump parts can seize or stick after being idle during the summer.

Typical repair cost £90-250 (including labour)

Engineer required

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

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Ravenheat models that show the 42E fault code

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

Source

Ravenheat 42E fault code information on this page is sourced and cross-checked against the official Ravenheat service / installation manuals for each affected model.

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