Boiler repair requires caution—these systems use gas, water, and electricity. Common fixes include repressurizing (adding water via the filling loop), replacing the pressure relief valve, and cleaning the heat exchanger. Error codes like F22, E119, or L2 often indicate specific faults. Annual servicing by a Gas Safe engineer is recommended for gas boilers. Our guides cover Vaillant, Worcester Bosch, Baxi, Ideal, and Viessmann. DIY tasks include bleeding radiators, checking pressure, and replacing pumps. For gas work, always use a qualified professional.