7
Troubleshooting Guide
Difficulty Possible Cause Correction
#1 check is fouled Remove and clean #1 check
Relief valve discharges water Relief valve does not properly close Service relief valve
while system is not flowing
Municipal water pressure is fluctuating Install check valve upstream
of backflow assembly
Fouled relief valve seat Service relief valve
Relief valve does not Incorrectly installed diaphragm Remove diaphragm and
shut off properly correctly install
Damaged rubber surface on piston Replace with new piston
Damaged or plugged pressure hose Repair or replace hose.
Relief Valve Replacement Parts Listing
ITEM DESCRIPTION ORDERING
NO. CODE
1. Relief Valve Assembly 7018107
2. Diaphragm, RV 7017809
3. Spring, RV 7013368
4. Spider Bushing, RV 7017811
5. Piston Assembly, RV* 7018227
6. Body, RV 7018889
7. Hose & Cover Plate Assembly 7018228
8. Screw, Cover RV 7017822
9. O-ring, Inlet coupler 7017826
10. ‘E’ Clip (5 per pack) 7017870
NS Sensing Elbow 7018888
ITEM DESCRIPTION USE FOR ORDERING
NO. CODE
NS Hose (
1
/2"x20") 2
1
⁄2" & 3 M400, M500 7018890
NS Hose (
1
/2"x24") 2
1
⁄2" & 3 M400 N & Z 7018891
NS Hose (
1
/2"x30") 6 M400, 2.5, 3, 4 M500, 7018892
2
1
⁄2", 3, 4 M400 N & Z,
2
1
⁄2", 3, 4 M500 N & Z,
2
1
⁄2" & 3 M500 N & Z BFG
NS Hose (
1
/2"x36") 8 & 10 M400, 7018893
6, 8, 10 M400 N & Z,
4 & 6 M400BFG N & Z,
6, 8, 10 M500,
6, 8, 10 M500 N & Z
4 & 6 M500BFG N & Z
*includes shutoff disc
1
6
7
2
9
10
4
3
5
8