A preheater for a fuel cell (1) comprises a catalytic burner (2) with an inlet fed by fuel rinse gas from the cell anode (1a) and an inlet fed by an oxygen-containing gas. There is a burner to a fuel cell cathode (1b) for the reaction gas that is warmed by the reaction between the gases in the burner. An independent claim is also included for a pre-warming process as above.
