Police say offenders entered the treatment room at the premises in Greenfields Lane and caused ‘considerable damage’.
It happened some time overnight between Friday and Saturday.
Police are appealing for information.
Call 101 quoting police incident number 227-S-301119 or Crimestoppers anonymously on 0800 555 111.
The football club suffered two break-ins in November, with damage done to light fittings and litter scattered.
It is also believed that the offenders smoked weed.
It is less than a year since the club was targeted by vandals who ripped apart the ground’s seating. The club had about five seats in the home and away end ripped apart in January.