July 2020
Installation, Operation and Maintenance Manual
VA-DC-000-1803 Rev. 2
32
Section 3: Actuator Reassembly
Actuator Reassembly
3.8
Actuator Testing
3.8.1
Leakage Test - All pneumatic areas where leakage to atmosphere may occur are
to be checked, using a commercial leak testing solution. All hydraulic connections
should be pressurized and checked for leaks.
!
CAUTION
Do not exceed maximum pressure. Pressure applied to the actuator is not to exceed the
maximum operating pressure rating listed on the actuator name tag. Test the actuator
using a properly adjusted self relieving regulator, with gauge.
3.8.2
Cycle the actuator five times at the maximum operating pressure (MOP) as listed
on the actuator name tag or the customer's normal actuator supply pressure. If
excessive leakage across the pistons is noted, generally a bubble which breaks
three seconds or less after starting to form, cycle the actuator five times as this will
allow the seals to seek their proper service condition.
NOTE:
If excessive leakage across the piston remains, the actuator must be disassembled, and the
cause of leakage must be determined and corrected.
3.8.3
Apply MOP pressure to the pressure port in inner end cap (3 - 10) and allow the
actuator to stabilize.
3.8.4
Apply a commercial leak testing solution to the following areas:
3.8.4.1
Joint between inner end cap (3 - 10) and cylinder (3 - 70). This checks
cylinder to inner end cap O-ring seal.
3.8.4.2
The port hole in the outer end cap (3 - 80). This checks the piston seal to
cylinder (3 - 70), O-ring seal (4 - 70), and rod seal (4 - 50).
3.8.4.3
The vent check port hole in housing. This checks Polypak seal (4 - 30) that
seals piston rod (3 - 40) to inner end cap (3 - 10).
3.8.4.4
Remove pressure from the pressure inlet port.
3.8.5
If an actuator was disassembled and repaired, the above leakage test must be
performed again.
3.8.6
Shell Pressure Test – Optional pressure test could be performed on PED certified
actuator by applying pressure to both sides of the piston simultaneously for a
period of two (2) minutes. If any leakage occurs across a static seal, the unit must
be disassembled, and the cause of leakage determined and corrected.
!
WARNING
PED pressure testing. The actuators main pressure bearing parts will be tested in controlled
conditions in accordance with the requirement of PED by pressuring both sides of the
piston to avoid damage and over torquing of the actuator components. If future testing in
the field is necessary, Emerson should be contacted for guidance.
