Service Instructions
124843E Rev. C
August 2015
40
Section 7: Troubleshooting
Troubleshooting
7�2
Operational Test
7.2.1
Full Stroke Test
The “Full Stroke Test” (“On-line”) must be performed to satisfy the PFD
AVG
(average probability of failure on demand) value. The full stroke test frequencies
will be defined by the final installer to achieve the defined SIL level.
7.2.1.1 Procedure
7.2.1.1.1 Stroke the actuator/valve assembly two complete open/close
cycles with complete closing of the valve.
7.2.1.1.2 Verify the open/close cycles functioned correctly (e.g.
check locally, or automatically via Logic solver, the correct
movement of the actuator/valve).
Upon successful completion of the above described Full Stroke Test procedure,
the “Test Coverage” can be considered 99%.
7.2.2
Partial Stroke Test (when requested)
The “Partial Stroke Test” (“On-line”) can be performed to improve the PFD
AVG
value and to satisfy PFD
AVG
(average probability of failure on demand) value.
A typical partial stroke value is 15% of the stroke and the recommended test
interval is about every one to three months.
7.2.2.1 Procedure
7.2.2.1.1 Operate the actuator/valve assembly for No° 1 open/close
cycles 15% of the stroke.
7.2.2.1.2 Verify the partial stroke test functioned correctly (e.g. check
locally, or automatically via logic solver, or via the PST system
the correct movement of the actuator/valve was 15% of the
stroke).
NOTE:
The above test is only applicable on systems equipped with a partial stroke
feature.
