splitshot
Head cook, Bottle washer, and Peace keeper.
I've got a 6" 880v that is leaking out of the relief valve during no flow in the system. I have worked on smaller units (825y) in the past, and 9 times out of 10, this is caused by sand getting between the disc and seat which leaves pits in the disc.
Link for the repair kit options:
880V - Repair Kits - FEBCO Backflow Prevention Products
Link for the repair kit options:
880V - Repair Kits - FEBCO Backflow Prevention Products