Quite easy. To make a visual approach (only available approach with no instruments working at the airfield), the reported ceiling must be at or above the initial approach level for the aircraft so cleared.
With no equipment working we couldn't get IFR arrivals below 6000ft.
So when we had broken or overcast at lets say 5000ft, we could not accept any visual approaches, but VFR flights could still fly with no problems
(With PUTUN holding now published as a coordinate and not a radial and dme from our VOR we can get IFR arrivals down to 2000ft, so that should help a bit)