No. A816 emerged from Eastleigh in August 1931 for trials, but was stopped when temperature variations within the condensing equipment caused water leakage. Modifications were made to improve the draughting of the locomotive, incorporating a box-like chimney attached to the condenser array by pipes. No. A816 was released for more trials, and produced performances well-below those displayed by the unmodified members of the class. The experiment was ended when the system's developers ran out of money, and the locomotive was converted back to standard form between May and August 1935, re-entering service as No. 1816.