Flowserve Valtek Beta Positioners for Control Valves - Manual (Page 19)

24-19 Flowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611
Beta Positioner Troubleshooting
Failure Probable Cause Corrective Action
Valve won’t stroke, 1. Tubing to wrong ports 1. Retube to correct ports (see “Installation”
no excessive air section)
is exhausting 2. Cam action reversed 2. Refer to installation section and reverse cam
from positioner 3. Lever arm stuck 3. Work with stuck arm until it freely turns
4. Pilot spool stuck 4. Work spool by hand until it freely moves, or
remove spool and spool valve body and clean
thoroughly; replace if necessary
5. I/P module filter plugged 5. Remove I/P module and replace filter
6. I/P module failure 6. Replace I/P module
7. I/P mounting bolts loose 7. Tighten mounting bolts
Actuator goes to full 1. Broken feedback spring 1. Replace feedback spring
signal position, regard- 2. Linkage is disconnected, 2. Check and tighten all bolts and nuts in linkage,
less of signal stuck or missing parts make sure linkage doesn’t stick.
3. Pilot spool stuck 3. Work spool by hand until it freely moves, or
remove spool and spool valve body and clean
thoroughly; replace if necessary. Do not apply
grease to spool valve.
4. I/P module orifice plugged 4. Return I/P module to factory for service
Calibration shifts 1. Loose positioner mounting 1. Remove cover and check three screws
holding positioner to bracket, check two bolts
holding bracket to yoke
2. Loose linkage 2. Tighten all nuts and bolts on linkage
3. Loose zero adjustment 3. Tighten zero adjustment locking knob or range
locking knob adjustment locking knob adjustment after
calibrating knob
4. Worn arms or pins 4. Replace arms or pins, and apply grease
5. I/P mounting bolts loose 5. Tighten mounting bolts
Excessive air con- 1. Air leakage from O-rings 1. Remove spool valve; Check O-rings and replace
sumption (other than if necessary
normal exhaust) 2. Air leakage from tubing 2. Tighten or replace tubing fittings
3. Leaky cylinder piston 3. Replace O-rings in cylinder
O-rings
Actuator strokes very 1. Connection between 1. Retighten summing beam to diaphragm assembly
slowly in one direction capsule and beam with nut bottomed out against coil of spring (See
only improperly adjusted step 6 in “Removal & Repair of Instrument
Capsule Assembly”)
2. Tubing to cylinder is 2. Locate faulty tube and replace it
restricted
3. I/P module filter plugged 3. Remove I/P module and replace filter
Erratic operation 1. Dirt build-up inside 1. Disassemble; clean spool and body; add air filter
spool valve to air supply; if air filter exists, replace cartridge
2. Bent spool 2. Replace spool and valve block
3. Broken linkage or 3. Replace broken parts
positioner parts