BoilerFaultCodesGrant Burner reset light red/green inverted flash (2.5s on, 0.5s off) Fault Code
Also written as BURNERRESETLIGHTREDGREENINVERTEDFLASH25SON05SOFF — same fault.
The Grant Burner reset light red/green inverted flash (2.5s on, 0.5s off) fault code means: your boiler's internal computer has detected an electrical fault with the valve that controls the fuel supply, causing the system to shut down for safety.. It appears on 1 Grant model in our database.
Technical description: Lockout: oil valve circuit driver failure — faulty oil valve or internal control circuit
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Grant models that show the Burner reset light red/green inverted flash (2.5s on, 0.5s off) fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Grant Burner reset light red/green inverted flash (2.5s on, 0.5s off) fault code information on this page is sourced and cross-checked against the official Grant service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 7 July 2026