Method for protecting components of a fuel cell system

A method for protecting components of a fuel cell system (1), the fuel cell system (1) having a fuel cell stack (101), an air path (10), an off-gas line (12), and a fuel line (20) with a recirculation circuit (50), the method comprising the steps of:

• monitoring the air path (10) for a fault;
• closing a first valve (61) which is situated in the air path (10) and closing a second valve (62) which is situated in the off-gas line (12);
• blocking a purge valve (41);
• reducing a pressure in the air path (10) upstream of the first valve (61);
• if further operation of the fuel cell system (1) is possible:
• increasing the pressure in the air path (10) upstream of the first valve (61);
• unblocking the purge valve (41);
• opening the first valve (61) and the second valve (62);
• further operating the fuel cell system (1),
• wherein the pressure in the air path (10) is stored between the first valve (61) and the fuel cell stack (101) at a time of closing the first valve (61) and the second valve (62), and the stored pressure is used as a reference value, and
• wherein prior to opening the first valve (61) and second valve (62), a pressure level of the air path (10) upstream of the first valve (61) is adjusted to a pressure level in a blocked region (63), the blocked region (63) being situated between the first valve (61) and the second valve (62) and surrounding a cathode side (105) of the fuel cell stack (101).