How much does it cost to fix Keston error code E04?

Typical repair cost for the Keston E04 fault is £0-120 including labour.

E04 High

Keston E04 Fault Code

Q: What does the Keston E04 fault code mean?

Your boiler has lost power or been turned off while already trying to report a different fault, and it needs a manual restart to identify the original problem.

The Keston E04 fault code means: your boiler has lost power or been turned off while already trying to report a different fault, and it needs a manual restart to identify the original problem.. It appears on 9 Keston models in our database.

Technical description: Power has been reset whilst boiler was in lockout

Typical repair cost £0-120 (including labour)

DIY fix possible

Locate the reset button on the boiler control panelPress and hold the reset button for 2 to 3 secondsWait for the boiler to restart and observe if a different fault code appears

Find a Gas Safe engineer

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

Gas Safe Register →

Keston models that show the E04 fault code

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

Source

Keston E04 fault code information on this page is sourced and cross-checked against the official Keston service / installation manuals for each affected model.

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