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STI S.r.l. – Via Dei Caravaggi 15, 24040 Levate (BG) – ITALY www.imi-critical.com
Manual 5100, rev. 06 06/2020 – RTC/RTCS
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7
Instructions for the operator
7.1 Start Up
During the start-up of the actuator, proceed as follows:
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Check that the pressure and quality of the air supply (filtering degree, dehydration) are as prescribed.
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Check that the feed voltage values of the electric components (solenoid valve coils, micro-switches,
pressure switches, etc.) are as prescribed.
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Check that the actuator controls work properly (remote control, local control, emergency controls, etc.)
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Check that the required remote signals (valve position, air pressure, etc.) are correct.
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Check that the setting of the components of the actuator control unit (pressure regulator, pressure
switches, flow control valves, etc.) meet the plant requirements.
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Check that there are not leak in the pneumatic connections. If necessary tighten the nuts of the pipe
fittings.
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Remove all rust and, in accordance with the applicable painting specifications, repair paint-coat that
has been damaged during transport, storage or assembly.
7.2 Stroke adjustment
Important
It is assumed that the following instructions are executed in the workshop
using air as the power fluid.
Instructions are applicable when the actuator is already installed on the valve.
It is important that the mechanical stops of the actuator (and not those of the valve) stop the rotary stroke
at both extreme valve positions (fully open and fully closed), except when different configuration is
required by the type of the valve (i.e,: eccentric butterfly valves,..).
The setting of the open/closed valve position is performed by adjusting the setting screws
foreseen into the end flange of the cylinder and on the side wall of the scotch yoke mechanism
(see Fig. 5 and Fig. 6) following the instructions listed here below.
