ARI Armaturen STOBU PN 40 EN - Manual (Page 11)

Operating and installation instructions
STOBU
®
PN16-40
Rev. 0040102000 1113 Page 2-11
9.0 Troubleshooting table
ATTENTION !
- read point 10.0 and 11.0 prior to dismantling and repair work!
- read point 6.0 before restarting the plant !
Fault Possible cause Corrective measures
No flow Valve closed. Open valve.
Flange covers not removed.
(pos. 25; fig. 1-2) Remove flange covers.
(pos. 25; fig. 1-2)
Little flow Valve not sufficiently open. Open valve.
Dirt sieve clogged. Clean / replace sieve.
Piping system clogged. Check piping system.
Valve difficult to move or
cannot be opened Spindle dry (pos.4; fig. 6) Grease spindle (pos. 4) (fig. 6)
(Lubricant: see page 9)
Stuffing box too tight (pos. 6; fig. 1-4) Slacken hex. nuts of stuffing box gland
(pos. 15) slightly, but not sufficiently to
cause leakage (fig. 1-4)
Wrong direction of rotation Turn in correct direction (anticlockwise
to open valve).
Valve spindle leaking Stuffing box gland (pos. 15) slack
(fig. 1-4). Tighten stuffing box gland (pos. 15)
until leakage stops.
-Hex. nut (fig. 1-4).
If necessary, renew packing in stuffing
box seal (pos. 6). Observe warnings
(fig. 6)!
Leakage across valve
seat. Valve not properly closed. Pull hand wheel tight without tools.
Seat (pos. 1.2) / plug (pos. 3) damaged
by foreign particles.
(fig. 1-4). Replaced valve, consult supplier/man-
ufacturer.
Pressure difference too high. Use a valve with balancing plug
(see point 5.3).
Medium contaminated
(suspended solids). Clean valve.
Install dirt screen upstream of valve.
Valve with throttling plug +
position indicator + lock-
ing device cannot be
opened. Locking device has been tightened. Release locking device.
Rattling / banging
of the plug design with
„loose plug“ Nominal diameter of the valve in com-
pliance to the flow rate is to big Choose smaller nominal diameter
Use a plug damper execution: see
medium
- high flow turbulences;
- the valve with loose plug is mounted
directly by a centrifuged pump;
- behind pressure reduction stations;
- behind pipe elbows;
- in compact plants;
- expansion joints are missing;
- the pump is not mounted on a
damper;
- there is no flow stabilizing pipe length;
- there is no start-up bypass line
Alter the system
Use a plug damper execution: see
medium
Flange broken between
valve and piping. Bolts tightened unevenly.
Mating flanges not properly aligned. Re-align piping and fit new valve!