NOVELTY - The fuel cell assembly comprises a main housing (12) having a main housing inner chamber (18) that is gas-tight with respect to the surroundings. In the inner chamber, a reformer, a reformer burner (22) supplying the reformer with thermal energy, and a fuel cell stack (20) are provided, where the main housing comprises an air connection (14, 16) and a fan, which sucks air through the air connection into the main housing inner chamber. The fuel cell stack is arranged in a fuel cell housing arranged inside the main housing inner chamber.    USE - Fuel cell assembly useful for fuel cell heaters.    ADVANTAGE - The fuel cell assembly can be simply and economically produced with high flexibility.    DETAILED DESCRIPTION - The fuel cell assembly comprises a main housing (12) having a main housing inner chamber (18) that is gas-tight with respect to the surroundings. In the inner chamber, a reformer, a reformer burner (22) supplying the reformer with thermal energy, and a fuel cell stack (20) are provided, where the main housing comprises an air connection (14, 16) and a fan, which sucks air through the air connection into the main housing inner chamber. The fuel cell stack is arranged in a fuel cell housing arranged inside the main housing inner chamber. The fuel cell housing is adapted to the shape of the fuel cell stack such that the housing encloses the fuel cell stack at a small distance. The fuel cell housing comprises an intake opening connected to the main housing inner chamber and a connection to an output line connected to the intake side of the fan, and a burner line, which is connected to an inlet opening of the reformer burner is connected to the pressure side of the fan. A further component of the fuel cell assembly is arranged in a separate housing arranged within the main housing inner chamber, which is adapted at the shape of the component so that it encloses the component with small distance. The separate housing has a connection on the burner line, which is connected gas tightly against the main housing inner chamber. A sensor device receives measured size characterizing the combustion quality, and a control device that compares the measured size with a target value and controls deviation of the fan receives the measured size on the target value. A condensate separator is arranged in a reformat line connected with the reformer for guiding the reformat gas provided through the reformer and is connected over a condensate line with a discharge line connected with the suction line for discharging the fluid condensate separated from the reformat gas stream flowing through the reformat line, in a fluid collection container. The discharge line possesses a larger cross-section than the suction line and/or the condensate line. The discharge line is connected with a siphon, whose barrier height is sufficiently large in order to suck the fluid into the suction line to prevent maximal power of the fan, and/or is emptied in the maximal leakage of the condensate separator through an emerging overpressure. A fluid collection container has overflow in order to discharge the fluid.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of a fuel cell assembly.    Main housing (12)    Air connection (14, 16)    Main housing inner chamber (18)    Fuel cell stack (20)    Reformer burner. (22)