Models CA4/SA4 are pressure reducing regulators used to control downstream (outlet or P2) pressure. Sizes are
3/4" (DN20), 1" (DN25), 1-1/2" (DN40), and 2" (DN50). With proper trim uti li za tion, the unit is suitable for liquid or
gaseous service. (NOTE: This product was formerly identifi ed as a Model C4 or S4; a Model CA4/SA4 and C4/S4
are one and the same product.)
SECTION II
11-13
II. REFERENCES
Refer to Technical Bulletin CA4/SA4-TB for tech ni-
cal specifi cations of a Model CA4/SA4 reg u la tor.
SECTION III
CAUTION
Installation of adequate overpressure pro tec tion
is recommended to pro tect the reg u la tor and all
downstream equip ment from dam age in the event
of reg u la tor failure.
III. INSTALLATION
1. Install per direction of fl ow arrow indicated on
body, or "IN" and "OUT" markings.
2. Regulator may be rotated around pipe axis 360
degrees. For ease of maintenance, the rec om mend ed orientation is with the loading chamber
(4) upwards.
ABBREVIATIONS
CCW – Counter Clockwise
CW – Clockwise
ITA – Inner Trim Assembly
CAUTION
DO NOT HYDROSTATIC TEST THROUGH AN
IN STALLED UNIT; ISOLATE REGULATOR FROM
TEST. The "Outlet" rating as printed on the
nameplate is the rec om mend ed “upper op er at ing limit” for the sens ing di a phragm. Higher
pres sures could cause internal dam age. In ad di tion, note on the nameplate that the Inlet and
Outlet pres sure and temperature ratings are at
different levels.
3. Provide space below, above, and around reg u la tor
for removal of parts during maintenance.
4. Install block valves and pressure gauges to pro vide means for adjustment, operation, bypass, or
removal of the regulator. A UHP fi lter is rec om-
mend ed before inlet to remove typical pipe line
debris from entering valve and damaging internal
“soft goods”, primarily the dynamic seal and valve
seat.
Recommended Piping Schematic
for Pressure Reducing Station
Page 2
SECTION IV
IV. PRINCIPLE OF OPERATION
1. When a loading pressure – P
the top side of a diaphragm, the outlet controlled
pressure – P2 – will balance at approximately
.90 – .98 of the loading pressure - PL. (NOTE:
Fluc tu a tions in P1 – Inlet Pressure will cause a
deviation in P2 – Outlet Pressure due to inverse
sym pa thet ic ratio effect.) See Section VIII.
2. Movement occurs as pressure variations register
on the diaphragm. The registering pressure is the
outlet, P2, or downstream pressure. The loading
– is applied to
Load
V. STARTUP
1 Start with the block valves closed.
2. Adjust the loading system pressure control de vice
so that main regulator is trying to be con trolled at
0 psig pressure.
3. If it is a “hot” piping system, and equipped with
a bypass valve, slowly open the bypass valve
to preheat the system piping and to allow slow
ex pan sion of the piping. Closely monitor outlet
(down stream) pressure via gauge to ensure not
over-pressurizing. NOTE: If no bypass valve is
in stalled, extra caution should be used in start ing
up a cold system; i.e. do everything slowly.
CAUTION
Do not walk away and leave a bypassed reg u la tor unattended!
pressure fl uid op pos es di a phragm move ment.
As outlet pres sure drops, the loading pressure
push es the di a phragm down, opening the port; as
outlet pres sure increases, the diaphragm pushes
up and the port opening closes.
3. A diaphragm failure will tend to cause the reg u la tor
to fall below setpoint. A loss of loading pres sure
while inlet pressure is imposed will cause the
regulator to fail close. A com plete diaphragm failure
will cause the inlet process fl uid to mix with the
loading fl uid.
SECTION V
tor is fl owing. If not, slowly increase the loading
pressure into the cover dome until fl ow be gins.
6. Continue to slowly open the inlet (upstream) block
valve until fully open.
7. Continue to slowly open the outlet (downstream)
block valve, especially when the downstream piping system isn’t pressurized. If the outlet (down stream) pressure exceeds the desired pres sure,
close the inlet block valve and go to Step 2. Close
bypass valve approximately 25%, and re peat
pro ce dure.
8. When fl ow is established steady enough that the
outlet (downstream) block valve is fully open, begin
to slowly close the bypass valve if installed.
9. Develop system fl ow to a level near its expected
normal rate, and reset the regulator set point by
increasing the loading pressure to increase outlet
pressure, or decreasing the loading pressure to
reduce outlet pres sure.
4. Crack open the outlet (downstream) block valve
to approximately 10% full open.
5. Slowly open the inlet (upstream) block valve to
about 25% open, observing the outlet (down stream) pres sure gauge. Determine if the reg u la-
VI. SHUTDOWN
1. Shutoff auxiliary loading pressure source. Close
inlet block valve.
2
10. Reduce system fl ow to a minimum level and ob-
serve pressure set point. Outlet pressure will rise
from the set point of Step 9. The maximum rise
in outlet pressure on decreasing fl ow should not
exceed the stated upper limit of the range spring
by greater than 10%. If it does, consult factory.
SECTION VI
2. Allow suffi cient time for the line pressure down-
stream of the inlet block valve to bleed down.
IOM-CA4/SA4
Page 3
3. Shutoff the outlet block valve.
4. Relieve the trapped upstream and down stream
pres sure and loading pres sure.
VII. MAINTENANCE
5. The regulator may now be disassembled for
inspection and pre ven ta tive main te nance while
in-line.
SECTION VII
A. General:
WARNING
SYSTEM UNDER PRESSURE. Prior to per form ing
any maintenance, isolate the reg u la tor from the
sys tem and relieve all pressure. Failure to do so
could result in personal injury.
1. The regulator may be serviced without re mov ing the regulator from pipeline. The reg u la tor
is designed with quick-change trim to simplify
maintenance.
2. Record the nameplate information to req ui si tion spare parts for the regulator. The in for ma tion should include: Size, Product Code,
and Serial Number.
3. Refer to Section IX for recommended spare
parts. Only use original equipment parts sup plied by Cashco/KM for re build ing or re pair ing
regulators.
4. Owner should refer to owner's procedures for
removal, handling, cleaning and disposal of
nonreuseable parts, i.e. seals, etc.
27
13
19
15
*
27.3
*
16
20
Type UC - U-Cup
Dynamic Seal
*
13
19
15
*
27.1
*
27.2
*
16
20
Type CP - Cap
Dynamic Seal
5. The Inner Trim is re moved and replaced in the
body (23) as an assemblage of parts. The
Inner Trim Assembly, here in af ter called ITA,
consists of the fol low ing parts:
Item Dynamic
No. Seal Type Part Description
13 ..................... All ..........................Piston-Guide Bearing
15 .....................All ................................ Cage O-ring Seal
27.3 .............. UC .......... U-Cup Seal w/Metal Energizer
6. A detailed view of the dynamic side seal parts
is shown in Figure 1; an assembled ITA in
Figure 2; and a cross-sectional drawing of
the entire regulator is shown in Figure 3.
IOM-CA4/SA4
Figure 1: Dynamic Side Seals
B. Main Regulator Disassembly:
1. Shut down system in accordance Section VI.
2. Disconnect loading pressure supply line from
loading chamber. Loosen the diaphragm
fl ange bolts (12) and nuts (11) uniformly.
Remove all bolting and nuts.
3. Place matchmarks on body (23) and loading
chamber (4) fl anges. Remove the loading
cham ber by lifting vertically. NOTE: Seal (28)
may fall out of loading chamber recess.
4. Remove diaphragm(s) (9) and examine to
de ter mine if failed. If diaphragms failed, de ter mine if op er at ing con di tions are ex ceed ing
designed pressure or tem per a ture limits.
5. Evenly loosen the three cage cap screws (18)
3
Page 4
in single revolution increments. The reg u la tor
con tains a lower return spring (22); the ITA
should rise as the cage cap screws (18) are
backed out evenly. A downward holding force
should be ap plied to the top of the piston-guide
bearing (13) to pre vent the ITA from pop ping
up as the last threads of the cage cap screws
(18) are disengaged. Remove washers (17).
6. Remove the ITA by pull ing up on the pistonguide bearing (13). Set ITA aside.
7. Remove the lower return spring (22) from
within the body (23).
8. Remove the cage o-ring seal (15).
9. Remove metal C-ring seal (28) from body (23)
di a phragm fl ange groove.
10. Clean all metal parts to be reused according to
owner's procedures. NOTE: Regulators are
originally supplied with a level of clean li ness
equal to Cashco cleaning standard #S-1662.
Contact factory for details.
d. Examine the com po nents (27.1, 27.2,
27.3) of the dy nam ic side seal (27) mech a nism to de ter mine if sig nifi cant leakage
was oc cur ring. If the dy nam ic side seal
shows signs of sig nifi cant leakage, de ter-
mine if op er at ing con di tions are ex ceed ing
pres sure, pres sure drop, or tem per a ture
lim its.
e. Remove dynamic side seal (27) com po-
nents and discard. Special care should be
taken when using “tools” to remove the
components to ensure that no scratches
are made to any portion of the piston- guide
bearing (13) groove.
f. Remove the shim (16) from within the
cage (19).
g. Remove seat ring (21); examine for signs
of leakage. If seat ring shows signs of
signifi cant leakage, determine if op er at ing
con di tions - pres sure, pressure drop, or
temperature ex ceed ddesign lim its.
2. Clean all metal parts to be reused according
to owner's procedures. NOTE: Regulators are
originally supplied with a level of clean li ness
equal to Cashco cleaning standard #S-1662.
Contact factory for details.
Figure 2: Assembled ITA, with
"UC" Dynamic Side Seal
C. Disassembly of the ITA:
1. To Disassemble the ITA (See Figure 2):
a. Hold the lower part of the valve plug
(20) in a bench vise; grasp in "smooth
jaws" directly under plug's (20) seating
disc portion on hub "fl ats" provided. Do
not hold on the ma chined sur face in the
plug's (20) spin dle area.
b. Using a special double-posted spanner
wrench fi tting, (to order see NOTE in
Section IX Parts Ordering Information),
turn the pis ton-guide bear ing (13) CCW
to loosen. The piston-guide bear ing (13)
may be re moved by hand after loos en ing.
c. Remove ITA from vise. Pull the valve plug
(20) down and out through the cage's (19)
bottom opening.
16
1. Remove and dis card the fol low ing parts:
o-ring (15), diaphragm(s) (9), seals (27, 28),
and seat ring (21). These parts MUST be
re placed with fac to ry supplied new parts.
2. Inspect the metal parts that will be reused. The
parts should be free of surface con tam i nants,
burrs, oxides, and scale. Rework and clean
the parts as necessary. Surface con di tions
that affect the regulator performance are stated
below; re place parts that can not be re worked
or cleaned.
3. QC Requirements:
a. Valve plug (20);
D. Inspection of Parts:
1. 16 rms
fi nish on its seating surface
for tight shutoff.
2. No major defects on bottom guide
spin dle.
b. Cage (19);
1. 16 rms fi nish on cylinder bore. No
“ledg es” formed due to wear from
moving dynamic side seal (27) or plug
(20).
4
IOM-CA4/SA4
Page 5
E. Reassembly of the ITA:
1. Installation of dynamic side seal (27) (See
Figure 1):
a. Type CP:
1. Stretch o-ring energizer/seal (27.2)
over low er cir cum fer ence of pistonguide bear ing (13), tak ing care not to
“cut” o-ring energizer/seal (27.2). Us ing thumbs, work the o-ring en er giz er/
seal into the groove of the piston-guide
bear ing.
NOTE: Use NO lubricants!
2. Position cap seal (27.1) ring with
rect an gu lar cross-section at end of
pis ton-guide bearing (13). Stretch
cap seal (27.1) over lower end of
piston-guide bear ing us ing thumbs
to work the cap seal onto the pistonguide bearing. DO NOT USE A TOOL
FOR THIS STEP. Con tin ue pressing
cap seal (27.1) up wards towards the
groove until the cap seal “snaps” into
the groove of the piston-guide bear ing.
3. Insert shim (16) into cage (19) and
al low to rest inside the cage (19).
4. Position piston-guide bearing (13)
over and into upper end of cage (19)
until the cap seal (27.1) edge touch es
the upper lip of the cage. While gently
applying force to press the pistonguide bearing (13) into the cage (19),
simultaneously use fi n gers to lightly
press the cap seal (27.1) in wards into
the groove of the piston-guide bearing
un til the cap seal (27.1) “slips into”
the cage (19). DO NOT use tools or
lu bri cant to en gage the cap seal (27.1)
into the cage (19). DO NOT press
down ward on pis ton-guide bearing
(13) too hard or fast - the cap seal
(27.1) may slide out of its groove and
become dam aged.
b. Type UC:
1. Position u-cup seal (27.3) over low er
circumference of piston-guide bear ing
(13). Ensure the u-cup seal (27.3) is
oriented with the center-open-down wards as shown in Fig ure 1, as the
u-cup seal (27.3) de pends upon the
P1-Inlet pressure to activate prop er
seal ing ac tion.
2. Insert shim (16) into cage (19) and
al low to rest inside the cage (19).
3. Position piston-guide bearing (13)
over and into upper end of cage (19)
until the cap seal (27.1) edge touch es
the upper lip of the cage. Gently apply
downward force to press the pis tonguide bearing (13) into the cage (19).
DO NOT use tools, lu bri cant, or heavy
force to en gage the u-cup seal (27.3)
into the cage (19).
2. Place properly oriented seat ring (21) onto its
shoul der at the lower end of cage (19).
3. Completion of ITA Reassembly.
a. Insert valve plug (20) upwards through
lower end of cage (19) and through the
center hole of shim (16).
b. Engage valve plug (20) with piston-guide
bearing (13) threads and fi nger tighten.
c. Place ITA into a vise with smooth jaws
and grasp at hub "fl ats" location on the
valve plug (20) that is not in the “spindle”
zone. (See Figure 2.)
d. Using a special double-posted spanner
wrench fi tting (to order see NOTE in
Section IX, Parts Ordering In for ma tion),
tighten the piston-guide bear ing (13) to
the valve plug (20) with 30 - 50 ft-lbs
(41-69 Nm). Do NOT allow valve plug
(20) to rotate against seat ring (21) during
tight en ing.
e. This completes ITA reassembly.
F. Main Regulator Reassembly:
1. Insert the return spring (22) into the body (23).
2. Fit cage O-ring seal (15) into the body (23)
groove.
3. With the ITA held manually in the closed po si tion, insert ITA and cage (19) into body (23).
4. Properly align all three cage bolt (18) holes as
there is only one proper alignment possible.
Ap ply a down ward force to the top of the
cage (19) until the ITA is lowered suf fi cient ly
to engage the cage bolts (18) with washers
(17) into the body (23). Engage all of the
cage bolts (18), then tighten the cage bolts
in al ter nat ing one-half rev o lu tion in cre ments
to pull down the ITA evenly. ENSURE THE
ITA DOES NOT BECOME WEDGED AS IT
IS SLID INTO THE BODY. Tight en the cage
bolts (18) to a torque value of 13-15 Ft-lbs
(17.5-20.5 Nm).
IOM-CA4/SA4
5
Page 6
5. Units with CTFE or VTFE seat ring (21): Due to
the relative "hardness" of the CTFE and VTFE
material, to obtain the best possible shutoff
it is nec es sary to generate a "coined" seating
chamfer.
6. To coin the seat ring:
a. Close-off the outlet connection.
b. The level of seat leakage can be quan ti-
fi ed at the internal sensing passage.
c. Pressurize the regulator's inlet with
50–100 psig (3.5–6.9 Barg) of UHP grade
GN2.
d. Place a thin, fl exible membrane that more
than covers the diaphragm fl ange cavity
of the body (23).
e. Using a soft-headed mallet (rubber,
leath er), sharply rap the thin membrane
over the top,center end of the piston-guide
bear ing (13). (Note: Gas will escape as
the plug (20) is momentarily forced off
the seat ring (21). Allow suf fi cient time
for leak age pres sure on outlet side to
bleed-off.) The ham mer rap should be
strong enough to "bounce" the plug (20)
into the seat ring (21), leav ing a "coined"
seating chamfer. Repeat a minimum of
2 times. Check after each rap to see if
re quired shut off is obtained.
f. After "coining" is complete, remove UHP
grade GN2 pres sure source, membrane
and open out let.
DO NOT HIGH STATIC PRESSURE TEST
THE BODY WITH OUT LOADING CHAMBER
PRES SUR IZED. NOT ADHERING WILL DO
PHYSICAL DAMAGE TO INTERNALS THAT
COULD REN DER THE UNIT INOPERABLE.
2. Seat Leakage Test.
a. Release all loading pressure from loading
chamber.
b. Pressurize inlet to 50 psig (3.5 Barg) with
UHP grade GN2.
c. Tube outlet to a beaker of water to ob-
serve number of escaping gas bubbles.
A steady fl ow of gas bubbles (e.g., 20
bub bles / minute or greater) is ex ces sive
leakage.
3. Excessive leakage will require disassembly,
examination of sealing elements, correction of
problem, reassembly and retesting. Leakage
path may be via plug/seat or dynamic side
seal.
NOTE: If disassembly and re-testing is
required, the metal C-ring seal (28) MUST
be re placed for each disassembly/re as sem bly.
7. To Install Diaphragm(s):
a. Install a new metal C-ring seal (28) into
the body (23) diaphragm fl ange groove.
b. Center diaphragm(s) (9) onto body's (23)
diaphragm fl ange.
8. Aligning matchmarks and bolt holes, place
loading chamber (4) on body (23).
9. Install all fl ange bolts (12) and nuts (11) with
nameplate (99) located under one bolt head.
Hand-tighten nuts (11).
10. Evenly tighten body bolting (11,12) using an
alternating cross pattern in one revolution
increments. Tighten to the following torque
value: All body sizes: 30-35 Ft-lbs (41-47 Nm).
G. Pressure Testing:
1. If a high static pressure test is performed,
pres sure must be applied to all three, the
loading chamber, the inlet and the outlet of
body at the same level.
6
IOM-CA4/SA4
Page 7
SECTION VIII
VIII. TROUBLE SHOOTING GUIDE
When trouble shooting this regulator there are many possibilities as to what may be causing problems. Many
times, the regulator itself is not defective, but one or more of the accessories may be. Sometimes the pro cess
may be causing diffi culties.
The key to effi cient trouble shooting is information and communication. The customer should try to be as precise
as possible in their explanation of the problem, as well as their understanding of the application and operating
con di tions.
It is imperative the following information be provided by the customer:
Fluid (with fl uid properties)
Range of fl ow rateRange of inlet pressure
Range of outlet pressure
Range of fl uid temperatureRange of ambient temperature
Pressure readings should be taken at every location that pressure plays a role - i.e., regulator inlet (as close as
possible to inlet port), regulator outlet (as close as possible to outlet port), etc.
Below are some of the more common complaints along with possible causes and remedies.
1. Erratic regulation, instability or hunting.
Possible CausesRemedies
A. Sticking of internal partsA. Remove internals, clean, and if necessary, replace.
B. Oversized regulatorB. Check actual fl ow conditions; resize regulator for min i mum
and maximum fl ow; if necessary, replace with smaller
regulator.
2. Downstream pressure will not reach desired setting.
Possible CausesRemedies
A. Supply pressure is down (confi irm
on pressure gauge).
B. Undersized regulator.B. Check actual fl ow conditions; resize regulator for minimum
3. Diaphragm continually breaks.
Possible CausesRemedies
A. Differential pressure across dia phragm may have exceeded limits.
(See Table 1 in Tech Bulletin).
A. Increase supply pressure
and maximum fl ow; if necessary, replace with larger regulator.
A. Be aware of limits as well as where the various pressures are
acting. Install pressure safety equipment as necessary.
Pressure limit for outlet is lower than the limit of the inlet.
IOM-CA4/SA4
7
Page 8
4. Leakage at diaphragm fl ange.
Possible CausesRemedies
A. Body bolts not torqued properly. A1. Torque to proper value (see Section VII, F.13).
A2. Failed C-ring seal. Replace seal.
B. Pressures at diaphragm may be too
high for regulator design.
5. Leakage across seat.
Possible CausesRemedies
A. Contamination (debris) in regulator. A1. Remove internals, clean and if necessary, replace sealing
B. Oversized regulator; plug operates
directly next to seat.
* Excess seat leakage may be diagnosed when a failure of the dynamic side seal has occurred. Inspect both
potential internal leak paths.
C. Failure due to wear. C1. Replace seat.
D. Improper installation. D1. Failure to "coin" CTFE or VTFE seat; disassemble and "coin".
B. Consult factory.
seating elements. *
A2. Install UHP fi lter at inlet.
B. Check actual fl ow conditions; resize regulator for minimum and
maximum fl ow; if necessary, replace with smaller regulator.
C2. Replace all internal trim due wear.
D2. Improper re-assembly. Disassemble and re-assemble per
instructions within IOM.
8
IOM-CA4/SA4
Page 9
SECTION IX
IX. ORDERING INFORMATION
NEW REPLACEMENT UNIT VS PARTS "KIT" FOR FIELD RE
To obtain a quotation or place an order, please retrieve the Serial Number and Product Code that was stamped on
the metal name plate and attached to the unit. This information can also be found on the Bill of Material ("BOM"),
a parts list that was provided when unit was originally shipped. (Serial Number typically 6 digits). Product Code
typical format as follows: (last digit is alpha character that refl ects revision level for the product).
–
NEW REPLACEMENT UNIT:
Contact your local Cashco, Inc., Sales Rep re sen ta tive with the Serial Number and Product code.
With this information they can provide a quotation
for a new unit including a complete description,
price and availability.
CAUTION
Do not attempt to alter the original construction
of any unit without assistance and approval from
the factory. All purposed changes will require a
new name plate with appropriate ratings and new
product code to accommodate the recommended
part(s) changes.
–
7
PARTS "KIT" for FIELD REPAIR:
Contact your local Cashco, Inc., Sales Rep re sen ta tive with the Serial Number and Product code.
Identify the parts and the quantity required to repair
the unit from the "BOM" sheet that was provided
when unit was originally shipped.
NOTE: Those part numbers that have a quantity indicated
under "Spare Parts" in column "A” refl ect minimum
parts required for inspection and rebuild, - "Soft
Goods Kit". Those in column “B” include minimum
trim replacement parts needed plus those "Soft
Goods" parts from column "A".
If the "BOM" is not available, refer to the crosssectional drawings included in this manual for part
identifi cation and selection.
A Local Sales Representative will provide quotation
for appropriate Kit Number, Price and Availability.
NOTE: In addition to ordering repair parts, it is recommended that a special double-posted spanner wrench
fi tting be ordered for use in the main te nance of the ITA.
Double-Posted Spanner Wrench Fitting
Body SizePart Number
AllA96-75-9-P0459-00
The contents of this publication are presented for informational purposes only, and while every effort has been made to ensure their accuracy, they are not to be
construed as warranties or guarantees, express or implied, regarding the products or services described herein or their use or applicability. We reserve the right to
modify or improve the designs or specifi cations of such product at any time without notice.
Cashco, Inc. does not assume responsibility for the selection, use or maintenance of any product. Responsibility for proper selection, use and maintenance of any
Cashco, Inc. product remains solely with the purchaser.
IOM-CA4/SA4
9
Page 10
NOTES
10
IOM-CA4/SA4
Page 11
NOTES
IOM-CA4/SA4
11
Page 12
Figure 3:
Model CA4/SA4
Item No. Description
4 Loading Chamber
9
Diaphragm
*
11 Flange Bolt Nuts
12
13
15
‡
*
Flange Bolt
Piston-Guide Bearing
Cage O-ring Seal
16 Shim
17 Cage Washer
18 Cage Cap Screw
19 Cage
20 Valve Plug
21 * Seat Ring
22 Return Spring