Absorption-type refrigerating machines operating on ammonia and water and equipped for automatic thermo-siphon circulation can be fueled with biogas. Since biogas is only the refrigerator’s external source of heat, just the burner itself has to be modified. Whenever a refrigerator is converted for operating on biogas, care must be taken to ensure that all safety features (safety pilot) function properly. Remote ignition via a piezoelectric element substantially increases the ease of operation.