Emerson Bettis CBB Series - Section 5: Troubleshooting; Fault Diagnosis and Remedies

October 2015
Service Instructions
VA001-196-30 Rev. 1
22
Section 5: Troubleshooting
Troubleshooting
Section 5: Troubleshooting
5�1 Fault Insertion
In the unlikely event of a fault developing, the following Fault Location Table is provided to
assist the service engineer. This table is designed to cover a wide a range of Emerson Bettis
actuators as possible. Reference to equipment not supplied should be ignored.
Table 5� Symptoms and Solutions Table
SYMPTOM POTENTIAL CAUSES REMEDY
Erratic movement
Irregular supply of operating
medium
Check operating medium for consistent
supply pressure and correct as
necessary
Inadequate lubrication Dismantle, relubricate and reassemble
Worn parts
Dismantle and visually inspect
forsignicantwearandactuator
replacement may be required
Defective valve Consult the valve OEM's documentation
Short stroke
Incorrectly set stops
(valve and/or actuator)
Check the position of the travel stops
and readjust as necessary
Hardened grease
Dismantle, remove any hard grease,
relubricate and reassemble
Debris left in the cylinder or
housing during maintenance
Disassemble cylinder assembly to
remove debris and reassemble cylinder
assembly as necessary
Defective valve Consult the valve OEM documentation
Apparent lack of torque
Inadequate supply pressure
Ensure supply pressure is above the
minimum operating pressure of the
actuator and that output torque
producedatsupplypressureexceeds
valve
torque demand
Incorrect speed control settings
Adjustspeedcontrolstoincreaseow
Exhaustportblocked
Removeandcleantheexhaustport
silencers and replace
Pipe work blocked, crushed
or leaking
Examinethepipeworkforblockages,
crushed pipe or leakage and clear or
replace
as necessary
Defective controls
Examinethecontrols,refurbish
or renew as necessary and refer
to component manufacturer's
documentation
Defective piston seal
Dismantle the cylinder assembly,
removethedefectivepistonsealandt
new seal
and reassemble
Defective rod seal
Dismantle the cylinder assembly,
removethedefectiverodsealandt
new seal and reassemble
Defective housing seal
Dismantle the housing assembly,
removethedefectivesealandtnew
seal and reassemble
High valve torque or valve seized Consult the valve OEM documentation