AT THE WATER MAIN AT THE HOUSE IT SPLITS OFF FOR THE HOUSE AND THE FIRE SPRINKLERS. FROM THE FIRE SPRINKLER SIDE IT TEES OFF FOR THE GARDEN SPRINKLERS. WHEN THE GARDEN SPRINKLERS FINISH THEIR CYCLE THE PIPE BANGS. I’M GUESSING THAT WHEN THE SPRINKLERS ARE ON IT’S DRAWING PRESSURE FROM THE FIRE SPRINLER LINE AT THE CHECK VALVE AND WHEN THE GARDEN SPRINKERS FINISH, WATER FILLS BACK UP TO THE CHECK VALVE.
WHERE CAN I TAP IN SO THIS WON’T HAPPEN?