Double Check Backflow Preventer Troubleshooting
| Symptom | Probable Cause | Remedy |
| Leaking check valve | Debris on seat or seal ring | Clean seat area |
| Damaged seat area | Replace check assembly | |
| Damaged seat o-ring | Replace seat o-ring | |
| Damaged bolt o-ring(s) on check retainer | Replace o-ring(s) | |
| Low or no flow | Device installed backwards | Verify direction of flow arrow |
| Gate valves not fully open | Turn handles counterclockwise. | |
| Low supply pressure | Attach pressure gauge to test cock #1 and verify pressure. |
Click below for installation and maintenance sheets:
350 (A, DA, or ADA) Installation and Maintenance sheet 2 1/2" - 6"
350 (A, DA, or
ADA) Installation and Maintenance sheet 8-10"
350
Installation and Maintenance sheet 3/4" & 1"
450 Installation and Maintenance sheet 2 1/2" - 3"
450 (DA)
Installation and Maintenance sheet 4" - 6"
450 (DA)
Installation and Maintenance sheet 8-10"
950XL
Installation and Maintenance sheet 3/4"-2"
Click here
for information on freeze protection.