cashco 987 Installation, Operation And Maintenance Manual - Page 4

Browse online or download pdf Installation, Operation And Maintenance Manual for Control Unit cashco 987. cashco 987 15 pages. Globe-style pneumatic control valve body iom

Print Page

8. Confirm the action of controller and positioner

– direct or reverse – are producing the de sired

response in the control unit. Con firm that the

control valve "fail" position is as re quired.

9. Hereafter, the procedure assumes that actual

fluid flow may be established. This may not

be practical/possible in all cases; if so, vary

pro ce dure as required.

Always "heat" or "cool" down the system pip ing

SLOWLY by opening the control valve station

bypass valve in small increments.

10. With one of the control valve station block

valves still closed, and the loop controller still

in "manual" mode, open bypass valve and vary

flow rate manually to observe the re sponse of

the controller and control valve unit together.

V. MAINTENANCE

WARNING

SYSTEM UNDER PRESSURE.

maintenance, isolate the valve/actuator from the sys tem

and relieve all pressure. Failure to do so could result in

personal injury.

A. General:

1. Maintenance procedures hereinafter are

based upon removal of the valve/actuator

unit from the pipeline where installed.

2. Owner should refer to Owner's procedures for

re mov al, handling and cleaning of non re us able

parts, i.e. gaskets, suitable sol vents, etc.

3. General service valves supplied from the

factory do not require use of any gasket

sealant.(See below for "oxygen cleaned"

valves.)

4. Valves originally supplied in accordance

with Option-55 require special cleaning

pro ce dures. Refer to Cashco Specification No.

S-1134 for details.

with Spec. #S-1134, the valve is suitable for

ox y gen service. Sealants and lubricants used

in reassembly of a valve unit for use in oxygen

service MUST be suitable for O

5. All indicated Item Numbers that are with

SECTION V

Prior to performing any

When in compliance

service.

11. Attempt to develop manual control of the

loop by opening/closing the manual bypass

as required, or by manually controlling

main stream flow as required.

12. When the control valve is partially open, crack

open slowly the closed block valve while

si mul ta neous ly closing the bypass valve.

Con tin ue this procedure until the bypass is

closed and the block valves are both fully

open. The system is still under "manual" mode

control, but all flow is passing thru the control

valve.

13. Vary controller "manual" SIG output until

match ing the "automatic" SIG output, then

change the mode of the controller over to

"automatic", and the loop will experience a

minimum of upset conditions, and will be in

automatic control.

re spect to the actuator assembly (AA) are in

parenthesis and underscored; i.e. (20). All

Item Numbers that are with respect to the body

assembly (BA) are not un der scored; i.e. (32).

Reference with respect to the positioner is in

double parentheses; i.e. ((AP)).

6. Special care must be exhibited when

ro tat ing the plug stem (4) in the body to

not mar that portion of the surface of the

stem (4) where it contacts with the packing

(10). To rotate the stem (4) use the jam nuts

or grasp stem with soft-jawed pliers. NOTE:

When using the jam nuts (17) to rotate the

stem (4), use the upper jam nut to rotate the

stem CW, and the lower jam nut to rotate

the stem CCW, when viewed from above the

valve stem.

7. Hereafter, whenever text has the following

notation, "(Note PA.)", the following text is

to be applied:

"For ATO-FC units ONLY, connect a

temporary air source to the actuator and

pressurize to a level sufficient to initiate

travel to approximately mid-stroke."

8. Hereafter, whenever text has the following

notation, "(Note RP.)", the following text is

to be applied:

IOM-987