STI RTQ Series, Instruction Manual, Page: 23 / 44

STI S.r.l. – Via Dei Caravaggi 15, 24040 Levate (BG) – ITALY www.imi-critical.com
Manual 5300, rev. 09 06/2020 – RTQS 19
8.3.1.2 Manual Override type HW/HWR
For this type of Manual Override a specific Instruction Manual 6005 is available.
Fig. 10 Type HW Fig. 11 Type HWR
8.3.2 Restoring automatic operation
In addition to the basic instructions enclosed in the specific Instruction Manuals 2094 and 6005, the
following steps, after the restoring of automatic operation, are recommended for actuators used in SIL
applications:
- restore the supply pressure inside the actuator’s cylinder;
- operate the actuator with supply pressure;
- by exhausting the supply pressure check that the actuator is able to reach the fully closed position,
in case of fail close actuator, or the fully open position in case of fail open
actuator: it is possible to verify the correctness of the fully stroked position by checking the position
indicator or limit switches, if fitted;
-
In case the actuator is not able to reach fully stroke, verify the position of manual override
following the instructions enclosed in the specific Instruction Manuals;
-
remove the label ENGAGED from the handwheels when used.
Important
ONLY for SIL APPLICATIONS
When mechanical override is engaged, inhibiting the safety function of the
actuator, a label with the word ENGAGED indicating this status of the actuator
is fixed by the operator between two rims of the handwheel.
(see Figures 10 and 11).
ENGAGED