Technical

Hi, I am new to running live steam and I have just broken the box open on my A3 that I have had unopened for nearly 10 years.  Thanks to Adrians Live Steam DVD I have started to run the loco on a rolling road, but I cant seem to cycle the regulator back to RED LED on position so the valve is stuck open.  Do I need to take the body off to investigate?  (I have tried to click it through (100 clicks) the whole cycle on the regulator but no joy in getting back to the closed position) Many thanks Luke