Issue
Possible Cause
Corrective Action
Notes
Main Valve will not
open
Closed isolation valves in pilot system.
Check isolation valves, ensure
open.
Insufficient supply pressure.
Check upstream pressure.
Depending on water
source, supply pressure
may not be controlled by
valve operator.
Main valve stem assembly corroded/
damaged.
Inspect stem assembly, clean/
replace if necessary.
Blockage in pilot system.
Inspect & clean any installed
pilot system strainers, check
orifice/speed controls for
blockages.
Missing fixed orifice assembly.
Verify installation of orifice;
replace if required/missing.
Pilot valve inlet isolation
valve can be used as a
makeshift orifice assembly
by partially opening from
full closed position.
Improperly configured opening speed
control (if equipped).
Adjust opening speed control
to verify functionality, adjust as
required.
Standard setting for
opening speed control is
11/2 - 21/2 turns open from
full closed position. Can
be adjusted in field.
Main Valve will not
close
Closed isolation valves in pilot system
Check isolation valves, ensure
open.
Diaphragm is damaged
Conduct diaphragm seal test,
repair and replace if necessary.
Main valve stem assembly corroded/
damaged.
Inspect stem assembly, clean/
replace if necessary.
Blockage in main valve.
Perform freedom of movement
test; if valve does not close,
disassemble and remove
blockage.
Worn/damaged valve seat.
Perform seat sealing check;
disassemble and inspect/repair
seat if required.
Troubleshooting Guide
6 IOM-A-ACV-912_612 2115
EDP# 1917034
© 2021 Watts
IOM-A-ACV-912_612 2115
EDP# 1917034
© 2021 Watts 7
