j coleman

the copper line is the air volume line which controls the switch cutin and cutout. If you have a tank with a bladder or liner, the tank is probably waterlogged which will make cycle continously. cutoff pump,drain the storage tank. take a air tank and fill back to cutin pressure of the pump usually 45 lbs. turn back on and let pump fill tank with water. make sure all faucets are in off position when refilling tank. should work properly at this time. if not, the liner may have a hole inside letting the tank fill outside of the liner.