August 2016
Installation and Operation Manual
Part Number: VA001-507-32, Rev. 1
36
Section 5: Operation
Operation
(M) Hand Pump Selection Valves: These two valves are engaged to isolate the control
system before using the hand pump. Note: Both selection valves are engaged at the
same time when the hand pump is used to open or close the actuator.
(X) Shuttle Valve; (Optional) Used with an optional pressure transmitter.
(P)
(Optional) ESD 3-Way Normally Open Solenoid Valve
(E)
(Optional) Hydraulic Accumulator w/nitrogen blanket charge: The accumulator is
used to stroke the actuator open or close with an additional override feature
(B)
(Optional) Nitrogen Relief Valve: The relief valve is provided to prevent the nitro-
gen gas pressure to reach an over pressurization point caused by the pump or excessive
thermal expansion.
(N) (Optional) Accumulator Isolation Valve: Used to isolate the accumulator for repair
or maintenance.
(AB) (Optional) Pressure Transmitter: Used to transmit the pressure required to stroke
the valve over time as a diagnostic feature.
(H) (Optional) Accumulator Isolation Valve: This valve allows the hydraulic pressure to
by-pass back to the reservoir.
(D) (Optional) Isolation Valve: Used to blow down or decay the nitrogen pressure from
the accumulator for repair or maintenance.
(A) (Optional) Pressure Gauge: Illustrates the accumulator nitrogen blanket pressure.
(O) (Optional) Hand Pump Isolation Valve: This valve isolates the ESD solenoid and
must be closed prior to using the hand pump for stroking the actuator open or closed.
(AC) (Optional) Shuttle Valve: This valve allows the actuator to close by either remote
electric by energizing the closing solenoid item (K) or by losing the electric signal thru
the ESD solenoid item (P).
(S) (Optional) Pressure Transmitter: Used to transmit the accumulator nitrogen blan-
ket pressure.
Summary of Contents for Bettis EHO
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