Watts S8 - Manual (Page 19)

1
Single & Double Check Assemblies
17
PROBLEM Should valve
CAUSE be replaced? SOLUTION
A. Double check valve fails to hold 1.0 PSID minimum.
A-1 Debris on check disc sealing surface. No Check valve must be disassembled and cleaned
A-2 Leaking gate valve No Gate valve must be disassembled and cleaned
A-3 Damaged seat disc or seat O-ring No Disassemble damage check and re place
A-4 Damaged guide holding check open No Disassemble and clean or replace if necessary
A-5 Weak or broken spring No Check valve must be disassembled and spring replaced
B Chatter during flow conditions
B-1 Worn, damaged or defective guide No Disassemble and repair or replace guide
C. Low flows passing through mainline valve (DCDA only)
C-1 Check(s) on mainline are fouled No Mainline check(s) must be disassembled and cleaned
C-2 Meter strainer on bypass line is plugged No Strainer must be disassembled and cleaned
C-3 Mainline seat disc or seat is damage No Disassemble damage seat disc or seat and replace
C-4 Broken mainline spring No Mainline check must be disassembled and spring replaced
Troubleshooting Guide
Double Check Valve Assemblies, Double Check Detector Assemblies