DiskFlo Control Valves
7
Failure
Probable Cause
Corrective Action
Valve moves to failure position, excessive air
1. Failure of actuator O-ring
1. Replace actuator stem O-ring
bleeding from transfer case
2. Failure of sliding seal assembly
2. Repair or replace stem adapter / linkage assembly
Jerky shaft rotation
1. Overtightened packing
1. Retighten packing box nuts to slightly over finger-tight
2. Improper adjustment of lever arm on shaft causing arm
2. Readjust lever arm (see step 1 in the
to contact transfer case thus failing to convert torque.
“Remounting Actuator” section)
3. Cylinder wall not lubricated
3. Lubricate cylinder wall with silicone lubricant
4. Worn piston O-ring allowing piston to gall on cylinder wall
4. Replace O-ring; if galling has occurred replace all damaged parts
5. Worn actuator stem O-ring causing ctuator stem to gall on stem collar
5. Replace O-ring; if actuator stem is galled replace it
6. Worn (or damaged) shaft bearings, shaft bearings or packing followers
6. Disassemble and inspect parts; replace any worn or damaged parts
Excessive leakage through seal
1. Improper adjustment of external stroke stops
1. See “Adjusting External Stroke Stops” section
2. Worn or damaged seat
2. Replace seat
3. Damaged ball seating surface
3. Replace disc and shaft
4. Improper handwheel adjustment acting as limitstop
4. Adjust handwheel until disc seats properly
5. Ball not centered in body I.D.
5. Center ball; replace damaged seals.
Leakage through line flanges
1. Dirty line gasket surfaces
1. Clean gasket surfaces and reinstall valve
2. Improper torque on line flanges
2. Tighten line flanges evenly and completely (see Table 1 for proper torque)
3. Flange or pipe misalignment
3. Realign flanged ends with piping.
4. Warn Gaskets
4. Replace Gaskets
Leakage through packing box
1. Loose packing box nuts
1. Tighten packing box nuts to slightly over finger-tight
2. Worn or damaged packing
2. Replace packing
3. Dirty or corroded packing
3. Clean body bore and stem, replace packing
Valve slams, won’t open, or
1. Improper valve installation
1. See step 2 in “Installation” section and
causes severe water hammer
correct flow direction
Shaft rotates, ball remains open or closed
1. Broken shaft
1. Replace shaft
Actuator operates, shaft does not rotate
1. Broken internal actuator parts
1. Refer to appropriate actuator Maintenance Instructions
Trouble shooting DiskFlo Valve
Figure 5: Exploded Body Sub-Assembly
Note : Item numbers correspond to bill of material of Valve. Please refer to it for specific part numbers.
Item No. Description
1 body
20 hard seat
21 seat insert
22 seat retainer
50 disk
51 shaft
52 taper pins
55 seat gasket
61 O-ring
80 gland flange
83 shaft bearing
85 packing retainer
87 packing follower
88 packing
93 packing spacer
109 packing box stud
117 packing box nut
122 shaft plug
123 clip
124 screw
85
88
93
88
87
80
109
117
51
83
50
83
52
122
61
1
21
55
20/22
123
124
