Working fluid composition for refrigerator, refrigerator oil and refrigerator

A working fluid composition for a refrigerating machine, comprising:

• a refrigerant comprising trifluoroiodomethane, difluoromethane (R32) and pentafluoroethane (R125), wherein a ratio of (R32 and trifluoroiodomethane):R125 is 80 to 95:20 to 5;
• and
• a refrigerating machine oil comprising
• a polyol ester of pentaerythritol and a fatty acid having 4 to 9 carbon atoms,
• a hindered phenol compound comprising 2,6-di-tert-butyl-p-cresol, and
• an acid scavenger being at least one selected from the group consisting of a glycidyl ether epoxy compound represented by the following formula (1) and a glycidyl ester epoxy compound represented by the following formula (2):
• wherein Ra represents an aryl group or an alkyl group having 5 to 18 carbon atoms, and Rb represents an alkyl group having 5 to 18 carbon atoms,
• wherein a content of the polyol ester is 90% by mass or more, a content of the hindered phenol compound is 0.8 to 3% by mass, and a content of the acid scavenger is 0.7 to 3% by mass, based on a total amount of the refrigerating machine oil;
• and
• wherein the working fluid composition comprises no unsaturated hydrofluorocarbon refrigerant.