Cashco DA5 User Manual
INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM)
IOM-DA5
MODEL DA5
DA5 - DIRECT-ACTING, SPRING LOADED
BACK PRESSURE REGULATOR
SECTION I
I. DESCRIPTION AND SCOPE
The Model DA5 is a spring operated back pressure regulator used to control upstream (inlet or P1) pressure. Sizes
are 1/2" (DN15), 3/4" (DN20), 1" (DN25), 1 1/4" (DN32), 1 1/2" (DN40), 2" (DN50), 2 1/2" (DN65), 3" (DN80) and
4" (DN100). With proper trim uti li za tion, the unit is suitable for liquid, gaseous, or steam service. The Model DA5
is available in a more common “reverse” fl ow direction arrangement, that is balanced against outlet pressure varia-
tions, and a “standard” fl ow direction arrangement that is unbalanced. Refer to Technical Bulletin DA5-TB for design
conditions and selection rec om men da tions. (NOTE: This product was formerly iden ti fi ed as a Model D5 or Type V;
a Model DA5, D5 and Type V are one and the same product.)
SECTION II
11/13
II. REFERENCES
Refer to Technical Bulletin DA5-TB and DAG-TB for
tech ni cal specifi cations of a Model DA5 regulator.
SECTION III
III. INSTALLATION
CAUTION
For welded installations, all internal trim parts, seals and
diaphragm(s) must be removed from reg u la tor body prior to
welding into pipeline. The heat of fusion welding will dam age non-metallic parts if not re moved. NOTE: This does
not apply to units equipped with extended pipe nip ples.
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 position is with the spring chamber (4)
upwards. In liquid service it is recommended that
the spring cham ber be oriented down wards, and
that a cus tom er supplied and installed vent valve
be pro vid ed at the external sensing connection
to bleed-off trapped gas/air under the diaphragm
during initial startup.
3. Provide space below, above, and around reg u la tor
for removal of parts during maintenance.
ABBREVIATIONS
CCW – Counter Clockwise
CW – Clockwise
ITA – Inner Trim Assembly
4. Install block valves and pressure gauges to pro vide means for adjustment, operation, bypass,
or removal of the regulator. A pipeline strainer is
recommended upstream of inlet port to remove
typical pipe line debris from entering valve and
damaging internal “soft goods”, primarily the dynamic side seal and V-TFE seat when applied.
5. Upstream Sensing Installation Considerations
– Internal or External Sensing:
a. The regulator may be installed with internal
or external sensing. Unless otherwise spec i fi ed, the regulator is supplied by the factory
with internal sensing. The regulator may be
con vert ed in the fi eld to external sensing. (See
Section VII maintenance, Part H – Converting
Internal/External Sensing.
b. Reference DAG-TB, Table DAG-12 for rec-
om men da tions for applying external pressure
sensing.
c. For internal sensing, no external line is re-
quired. For external sensing, use an external
control line. The line is connected from the
port 1/4" (DN8) NPT on the side of the body
di a phragm fl ange (see following schematic)
to a pressure tap upstream of the regulator.
A tubing outside diameter of 0.25 inch is
adequate for short sensing lines (less than
4 feet). Use 3/8" tubing or 1/4" schedule 40
pipe for sensing lines of 5 to 50 feet.
d. For condensable vapors (i.e. steam) slope the
external sensing line downward 2 to 5 de grees
to inlet piping to prevent water pock ets, which
allows the diaphragm chamber to al ways be
self draining. The external sensing line may
be sloped upward for gas or liquid service;
i.e. non-condensibles.
CAUTION
DO NOT HYDROSTATIC TEST THROUGH AN IN STALLED
UNIT; ISOLATE REGULATOR FROM TEST. The upper
range spring pres sure level on the name plate 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. See Table 2 in DA5-TB for pressure limits of different
diaphragm materials.
SECTION IV
CAUTION
Installation of adequate overpressure pro tec tion is recommended to pro tect the reg u la tor from over pres sure and
all down stream equip ment from dam age in the event of
regulator failure.
Recommended Piping Schematic
For Back Pressure/Relief Station
IV. PRINCIPLE OF OPERATION
1. Movement occurs as pressure variations register
on the diaphragm. The registering pressure is the
inlet, P1, or upstream pressure. The range spring
op pos es di a phragm movement. As inlet pres sure
in creas es, the diaphragm pushes the range spring
V. STARTUP
1 Start with the block valves closed.
2. Relax the range spring by turning the ad just ing
screw CCW (viewed from above) a minimum of
three (3) full rev o lu tions. This reduces the inlet
(upstream) pres sure set point.
3. Crack open manual bypass valve. Initially pres sur ize system while simultaneously controlling
P1 pressure through manual actuation of bypass
valve.
up,lifting the valve plug further off the seat; as inlet
pres sure decreases, the range spring pushes the
di a phragm down closing the valve plug toward the
seat.
2. A complete diaphragm failure will cause the reg u la tor to fail closed and process fl uid will discharge
from the spring chamber vent hole.
SECTION V
trap op er a tion if in stalled. Close ly monitor inlet
(up stream) pres sure via gauge to ensure not
over-pres sur iz ing. NOTE: If no by pass valve is
in stalled, extra cau tion should be used in starting
up a cold system; (i.e., do ev ery thing slowly).
5. Open the outlet (downstream) block valve.
6. Slowly open the inlet (upstream) block valve to
about 25% open, observing the inlet (upstream)
pres sure gauge. Determine if the reg u la tor is
fl owing. If not, slowly rotate the regulator ad just ing screw CCW (viewed from above) until fl ow
be gins.
CAUTION
Do not walk away and leave a bypassed reg u la tor unattended!
4. 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. Ensure proper steam
2
7. When fl ow is established steady enough that
the inlet (upstream) block valve can be fully
opened, begin to slowly close the bypass valve if
installed.
8. Develop system fl ow to a level near its expected
normal rate, and reset the regulator set point by
turning the adjusting screw CW to increase inlet
pressure, or CCW to reduce inlet pressure.
IOM-DA5
9. Reduce system fl ow to a minimum level and ob-
serve pressure set point. Inlet pressure will decrease from the set point of Step 8. The max i mum
SECTION VI
build in inlet pressure on increasing fl ow should not
exceed the stated upper limit of the range spring
by greater than 30%. If it does, consult factory.
VI. SHUTDOWN
1. Shutoff inlet block valve.
2. Remove range spring compression by turning the
adjusting screw CCW to reduce the inlet pressure.
VII. MAINTENANCE
A. General:
1. The regulator may be serviced without re mov ing the regulator from pipeline. The
regulator 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, KM Product
Code, Serial Number.
3. Refer to Section IX for selection of 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. gaskets, etc.
NOTE: On regulators originally supplied as
“oxygen clean” – Opt-55, maintenance must
include a level of cleanliness equal to Cashco
cleaning standard #S-1134.
5. The Inner Trim Assembly (ITA) is re moved and
re placed in the body (23) as an as sem blage
of parts. The ITA consists of the fol low ing
parts:
3. Shutoff the outlet block valve.
4. Relieve the trapped upstream and downstream
pres sure.
5. The regulator may now be removed from the
pipe line or disassembled for inspection and pre ven ta tive main te nance while in-line.
SECTION VII
Item Dynamic Side
No. Seal Type Part Description
7 ......................All ...........................Diaphragm Fastener
(Cap Screw or Locknut)
8 ......................All .......Upper Diaphragm Pressure Plate
9 ......................All ......................................Diaphragm(s)
10 .....................All ..........Lower Diaphragm Pusher Plate
13 .................... All......................... Piston/Guide Bearing√
14 .....................All ......................................... Stem Seals
14.1 ............... All ................................ Upper Stem Seal
14.2 ............... All ................................Middle Stem Seal
14.3 ............... All ..............................Lower Stem Seal√
14.4 ............... All ................Lower Pusher Plate Gasket
20 .....................All ...........................................Valve Plug
27 .....................All ...........................Dynamic Side Seal *
27.1 ...............CP ..................................... TFE Cap Seal
27.2 ...............CP ......................... O-ring Energizer/Seal
27.3 .............. UC .......... U-Cup Seal w/Metal Energizer
27.5 ...............PR ................................. Piston Ring Seal
27.6 ...............PR ................. Piston Ring SST Energizer
28 .....................All ............................................ Seat Disc
29 .....................All ...............................Seat Disc Washer
30 .....................All ......................................Seat Disc Nut
* The Dynamic Side Seal (27) and the Cage Seal (15) are
omitted for the FTC fl ow direction regulator. This is Type
NO. See Figure 1.
√ 2-1/2" thru 4" body sizes only.
A detailed view of the dynamic side seal parts is
shown in Figure 1 on the next page.
IOM-DA5 3
Figure 1: Dynamic Side Seals
(FTC Flow Direction Only)
4
IOM-DA5
B. Main Valve Disassembly:
NOTE: Valves with “Large Internal Sensing” will not
be equipped with any plug (32,33).
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.*
* Includes external sensing connection if applicable.
1. Shut down the system in accordance with
15. For metal diaphragm constructions, remove
diaphragm gasket (37) from body (23) di a phragm fl ange.
16. Remove body (23) from vise. Solvent clean
all removed metal parts.
C. Disassembly of the ITA:
Section VI.
1. Body Sizes 1/2" – 2". (See Figures 3 and 4):
2. Disconnect the external sensing line, if in stalled.
a. Obtain two pieces of square-section
barstock with a 3/8"-7/16" dimension,
approximately 2 inches long.
3. Though it is possible to disassemble the regulator while installed in a pipe line, it is rec om mend ed that main te nance be done in a shop
when pos si ble. The de scrip tions here af ter will
assume shop dis as sem bly. Remove regulator
from pipe line.
b. Place plug (20) into a vise using the bars
of a. above, use "fl ats" located on plug
(20) to prevent vise jaw marks from direct
surface contact with the plug (20). Orient
with diaphragms on topside.
c. Sizes 1/2"-1": Remove diaphragm lock nut
(7) by rotating CCW.
4. Place the body (23) in a vise with the spring
chamber (4) oriented upwards.
Sizes 1-1/4"-2": Remove diaphragm cap-
screw (7) by rotating CCW.
d. Remove upper diaphragm pressure plate
5. Loosen adjusting screw lock nut (2) and relax
range spring (6) forces by turning adjusting
screw (1) CCW (viewed from above) until
removed from spring chamber (4).
(8).
e. Remove diaphragm(s) (9, 9.1, 9.2, 9.9).
Examine diaphragm(s) to determine
wheth er failed; determine if op er at ing
conditions are ex ceed ing pressure drop
6. Loosen the diaphragm fl ange bolts (11) and
nuts (12) uniformly.
or temperature lim its.
f. For composition diaphragm con struc tion,
remove upper stem seal (14.1).
7. Place matchmarks on body (23) and spring
chamber (4) fl anges. Com plete ly remove bolt-
ing (11,12) Re move the spring cham ber (4).
g. For metal diaphragm con struc tion, re move
lower pusher plate gasket (14.4).
h. Remove lower diaphragm pusher plate
(10).
8. Remove spring follower (5) and range spring
(6).
i. Remove middle stem seal (14.2).
j. Remove plug (20) from vise, ro tate end-
for-end, and resecure in vise using same
9. Grasp opposite edges of diaphragm (9) and
withdraw the ITA from within the cage (19).
Set the ITA aside.
metal bars above.
k. Loosen seat disc nut (30) CCW (viewed
from above) ap prox i mate ly two (2) rev o lu tions.
10. Evenly loosen the cage cap screws (18) in
single revolution increments until fully loos ened; remove cage cap screws (18).
l. Remove assembly (20, 27, 28, 29, 30)
from vise. Complete re mov al of seat disc
nut (30), seat disc washer (29), and seat
disc (28).
11. Pull cage (19) up and out of body.
2. Body Sizes 2-1/2" – 4". (See Figure 2):
12. Remove o-ring cage seal (15).
a. Place seat disc nut (30) into a vise with
the plug (20) oriented ver ti cal ly. DO NOT
13. Remove lower cage gasket (21).
over-tighten nut (30) in vise.
b. Place closed-end hex wrench onto di a-
14. If supplied, remove internal sensing drilled plug
(32) using 5/32" (4 mm) Allen key wrench for
1/2" - 2" size regulators. Use 3/16" Allen key
wrench for 2 1/2" - 4" size regulators.
phragm locknut (7). Place sock et wrench
on hex upper end of plug (20). Loos en
diaphragm lock nut (7) while holding plug
(20) from ro tat ing by socket wrench.
IOM-DA5 5
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