Catalyzes the reversible cleavage of pseudouridine 5'-phosphate (PsiMP) to ribose 5-phosphate and uracil. Functions biologically in the cleavage direction, as part of a pseudouridine degradation pathway. D-ribose 5-phosphate + uracil = H2O + psi-UMP Binds 1 Mn(2+) ion per subunit. Homotrimer. Belongs to the pseudouridine-5'-phosphate glycosidase family.