Cashco 964 - Manual (Page 3)

IOM-964 3
11. Undue piping stress/strain or bend ing
torques may not be trans mit ted thru the
valve body. One pipe (inlet or outlet) should
be an chored rig id ly for pip ing that is “hot” or
“cold” with respect to ambient tem per a ture;
the re main ing pipe (in let or out let) should
be sup port ed and guid ed to ensure uni di-
rec tion al ex pan sion/con trac tion.
C. Air Supply:
1. Use a desiccant dried, instrument quality
air supply. Such a supply is recommended
for outdoor installations, and is required in
areas of freezing weather conditions.
SECTION IV
IV. START-UP
A. General:
1. Ensure that the Model 964 unit has been
prop er ly adjusted and cal i brat ed, in clud ing
the po si tion er, if in stalled.
2. Recommend startup to be in a “man u al”
mode. This pro ce dure assumes dou ble
block (iso la tion) and bypass valves for the
“control valve station”. See Fig ure 1.
3. Start with either of the two block valves
closed, with the other open. The bypass
valve should be closed. Pres sur ize sys tem,
if pos si ble/prac ti cal.
4. Back out the airset’s adjusting screw until
loose.
5. Turn on air supply pressure.
6. Adjust the air supply airset (fi l ter-reg u la tor)
to the proper lev el as in di cat ed as follows:
8. Confi rm that action of con trol ler and po si-
tion er - direct or reverse - are producing
the de sired re sponse in the con trol unit.
Con fi rm that the con trol valve “fail” po si tion
is as re quired.
9. Hereafter, the procedure as sumes that ac tu al
fl uid fl ow may be established. This may not
be practical / pos si ble in all cas es; if so, vary
procedure as re quired.
Always “heat” or “cool” down the system
pip ing SLOW LY by open ing the control valve
sta tion by pass valve in small in cre ments.
10. With one of the control valve station block
valves still closed, and the loop con trol ler
still in “man u al” mode, open by pass valve
and vary fl ow rate man u al ly to ob serve the
re sponse of the con trol ler and control valve
unit to geth er.
11. Attempt to develop manual con trol of the
loop by opening/clos ing the man u al by pass
as re quired, or by manually con trol ling main-
stream fl ow as re quired.
12. When the control valve is partially open, crack
open slowly the closed block valve while
si mul ta neous ly clos ing the by pass valve.
Con tin ue this pro ce dure until the bypass is
closed and the block valves are both fully
open. The system is still under “man u al”
Bench Setting Airset Output
psig (Barg) psig (Barg)
5–15 (.34–1.0) 20 (1.4)
15–60 (1.0–4.1) 75 (5.2)
2. If air supply contains moisture and /or lu-
bricating oil, the air should be fi ltered with
a coalescing type of fi lter prior to use in
stroking the actuator.
3. Failure to remove moisture will cause corro-
sion to the internals of the actuator casings.
4. Connections for the air supply are 1/4" female
NPT. Use a suitable pipe thread sealant
when installing the pipe or tube fi tting. DO
NOT allow sealant to enter the tube/pipe.
7. Place loop controller into “man u al” mode.
Vary setting from minimum - mid-range -
max i mum SIG output. Ob serve re sponse of
con trol valve unit to these chang es of input
SIG. The valve should fully stroke at the
vari a tion from min i mum SIG to max i mum
SIG; the mid-range SIG should have the
valve stem travel at/near 1/2 open.
CAUTION
DO NOT WALK AWAY AND LEAVE A MANUALLY CON-
TROLLED CONTROL VALVE UNATTENDED!