Medium
EF 349 on Worcester Bosch 30i Junior

Your boiler is working harder than it should because water isn't moving through the system quickly enough to take away the heat.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

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This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description

Central heating boil detected – boiler operating at minimum burner load with temperature difference greater than 18°C between Flow & Return.

DIY fix possible

Check that all radiator valves are fully openEnsure the central heating system pressure is between 1 and 1.5 barBleed all radiators to remove trapped airCheck for any visible leaks around the pipework

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