cashco DA1 Instruction manual

INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM) IOM-DA1
12-16
I. DESCRIPTION AND SCOPE
The Model DA1 is a pressure reducing regulator used to control downstream (outlet or P2) pressure. Sizes are
1/2" (DN15), 3/4" (DN20), 1" (DN25), 1-1/4" (DN32),1-1/2" (DN40), 2" (DN50), 3" (DN80) and 4" (DN100).
With proper trim utilization, the unit is suitable for liquid, gaseous, or steam service. Refer to Technical Bulletin
DA1-TB for design conditions and selection recommendations. (NOTE: This product was formerly identified as
a Model D1; a Model DA1 and D1 are one and the same product.)
MODEL DA1
DA1 - DIRECT-ACTING, SPRING LOADED
PRESSURE REDUCING REGULATOR
SECTION I
II. REFERENCES
Refer to Technical Bulletin DA1-TB and DAG-TB for
technical specifications of a Model DA1 regulator.
ABBREVIATIONS
CCW – Counter Clockwise
CW – Clockwise
ITA – Inner Trim Assembly
III. INSTALLATION pipeline debris from entering valve and damaging
internal “soft goods”, primarily the dynamic seal(27)
and the V-TFE seat (21) when applied.
4. Downstream Sensing Installation Considerations
– Internal or External Sensing:
a. The regulator may be installed with inter-
nal or external sensing. Unless otherwise
specified, the regulator is supplied by factory
with internal sensing. The regulator may be
converted in the field to external sensing (see
Section VII Maintenance, Paragraph H).
b. Reference DAG-TB, Table DAG-11 for rec-
ommendations 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" NPT) on the side of the body diaphragm
flange (see port 5 in Fig. 5) to a pressure tap
10 to 15 pipe diameters downstream of the
regulator. Use 1/4" or 3/8" outer diameter
tubing or 3/8" (DN10) pipe having an inner
diameter equivalent to schedule 40 pipe.
d. For condensable vapors (i.e. steam) slope the
external sensing line downward 2 to 5 degrees
to outlet piping to prevent water pockets,
SECTION III
SECTION II
For welded installations, all internal trim parts,
seals and diaphragm(s) must be removed from
regulator body prior to welding into pipeline. The
heat of fusion welding will damage non-metallic
parts if not removed. NOTE: This does not apply
to units equipped with extended pipe nipples.
CAUTION
1. Regulator may be rotated around pipe axis 360
degrees. For ease of maintenance, the recom-
mended position is with the spring chamber (4)
upwards. In liquid service it is recommended that
the spring chamber (4) be oriented downwards, and
that a customer supplied and installed vent valve
be provided at the external sensing connection to
bleed-off trapped gas/air under the diaphragm.
2. Provide space below, above, and around regulator
for removal of parts during maintenance.
3. Install block valves and pressure gauges to pro-
vide means for adjustment, operation, bypass,
or removal of the regulator. A pipeline strainer
is recommended before inlet to remove typical
ISO Registered Company

IOM-DA12
which allows the diaphragm chamber to
always be self draining. The external sensing
line may be sloped upward for liquids or gases.
CAUTION
DO NOT HYDROSTATIC TEST THROUGH AN
INSTALLEDUNIT;ISOLATEREGULATORFROM
TEST. The upper range spring pressure level
on the nameplate is the recommended “upper
operating limit” for the sensing diaphragm.
Higher pressures could cause internal damage.
In addition, note on the nameplate that the Inlet
and Outlet pressure and temperature ratings
are at different levels.
Recommended Piping Schematic
For Pressure Reducing Station
IV. PRINCIPLE OF OPERATION
1. Movement occurs as pressure variations register
on the diaphragm. The registering pressure is the
outlet, P2, or downstream pressure. The range
spring opposes diaphragm movement. As outlet
pressure drops, the range spring pushes the dia-
phragm down, opening the port; as outlet pressure
V. STARTUP
1. Start with the block valves closed.
2. Relax the range spring by turning the adjusting
screw CCW (viewed from above) a minimum of
three (3) full revolutions. This reduces the outlet
(downstream) pressure set point.
3. If it is a “hot” piping system, and equipped with
a bypass valve, partially open the bypass valve
to preheat the system piping and to allow slow
expansion of the piping. Ensure proper steam
trap operation if installed. Closely monitor outlet
(downstream) pressure via gauge to ensure not
over-pressurizing. NOTE: If no bypass valve is
installed, extra caution should be used in starting
up a cold system; i.e. do everything slowly.
4. Crack open the outlet (downstream) block valve.
5. Slowly open the inlet (upstream) block valve to
about 25% open, observing the outlet (down-
stream) pressure gauge. Determine if the regu-
lator is flowing. If not, slowly rotate the regulator
adjusting screw CW (viewed from above) until
flow begins.
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 pip-
ing system isn’t pressurized. If the outlet (down-
stream) pressure exceeds the desired pressure,
close the inlet block valve and go to Step 2. Close
bypass valve approximately 25%, and repeat
procedure.
8. When flow is established steady enough that the
outlet (downstream) block valve is fully open, begin
to slowly close the bypass valve if installed.
increases, the diaphragm pushes up and the port
opening closes.
2. A complete diaphragm failure will cause the regu-
lator to fail open and fluid will discharge from the
spring chamber vent hole.
SECTION IV
SECTION V
CAUTION
Do not walk away and leave a bypassed regulator
unattended!
Supply
@ P1
Model DA1
Reducing
Regulator
SRV P1
Outlet
@ P2
Bypass
Blowdown-
Drain
Blowdown-
Drain
(Shaded portion for steam/condensate systems)
TR TR
CAUTION
Installation of adequate overpressure protection
is recommended to protect the regulator from
overpressure and all downstream equipment from
damage in the event of regulator failure.

3
IOM-DA1
9. Develop system flow to a level near its expected
normal rate, and reset the regulator set point by
turning the adjusting screw CW to increase outlet
pressure, or CCW to reduce outlet pressure.
10. Reduce system flow to a minimum level and ob-
serve pressure set point. Outlet pressure will rise
SECTION VI
VI. SHUTDOWN
1. Shutoff inlet block valve.
2. Allow sufficient time for the line pressure down-
stream of the inlet block valve to bleed down.
3. Shutoff the outlet block valve.
4. Relieve the trapped upstream and downstream
pressure.
5. The regulator may now be removed from the
pipeline or disassembled for inspection and pre-
ventative maintenance while in-line.
VII. MAINTENANCE
A. General:
1. The regulator may be serviced without remov-
ing the regulator from pipeline. The regulator
is designed with quick-change trim to simplify
maintenance.
2. Record the nameplate information to req-
uisition spare parts for the regulator. The
information should include: size, Product
Code, Serial Number, and internal or external
sensing. (NOTE: Never both types of sens-
ing.) If external sensing is used, be sure that
the external sensing line is connected.
3. Refer to Section IX for recommended spare
parts. Only use original equipment parts
supplied by Cashco for rebuilding or repairing
regulators.
4. Owner should refer to owner's procedures for
removal, handling, cleaning and disposal of
nonreusable parts, i.e. gaskets, etc.
NOTE: On regulators originally supplied as
Special Cleaning Option-55, -56, or -57,
maintenance must include a level of cleanli-
ness equal to Cashco cleaning standards of
#S-1134, #S-1542, and #S-1589 respectively.
Contact factory for details.
Item Dynamic
No. Seal Type Part Description
13 ..................... All ..........................Guide Bearing/Piston
14 ..................... All .................................. StaticStem Seal
14.1 ............... All ...................... Upper Static Stem Seal
14.2 ............... All ......................Middle Static Stem Seal
14.3 ............... All ...................... Lower Static Stem Seal
15 ..................... All ................................Cage O-ring Seal
16 .................CW,PW.............................................. Wiper
17.1 ..............CW,PW................................. Wiper Washer
17.2 ........... OR,CP,PR ........ Camber Adjusting Washer *
17.3 ................. UC ..................................... Seal Retainer
19 ..................... All ................................................... Cage
20 ..................... All ...........................................Valve Plug
21 ..................... All ............................................ Seat Ring
27 ..................... All ............................. Dynamic Side Seal
27.1 ........... CP,CW ................................. TFE Cap Seal
27.2 ...........CP, CW..................... O-ring Energizer/Seal
27.3 .............. UC .......... U-Cup Seal w/Metal Energizer
27.4 .............. OR ....................................... O-Ring Seal
27.5 ........... PR,PW ............................. Piston Ring Seal
27.6 ........... PR,PW ............. Piston Ring SST Energizer
* Metal Diaphragm Only.
SECTION VII
5. The Inner Trim is removed and replaced in the
body ( 23) as an assemblage of parts. The
Inner Trim Assembly, hereinafter called ITA,
consists of the following parts:
A detailed view of the dynamic side seal parts
is shown in Figure 1 on the next page.
from the set point of Step 9. The maximum rise
in outlet pressure on decreasing flow should not
exceed the stated upper value of the range spring
by greater than 10%. If it does, consult factory.

IOM-DA14
Figure 1: Dynamic Side Seals
Type OR — O-Ring
Dynamic Seal
Type CW — TFE Cap
Dynamic Seal + Wiper
Type CP— TFE Cap
Dynamic Seal
Type PR — PRA
Dynamic Seal
Type PW — PRA Dynamic
Seal + Wiper
Type UC — U-Cup
Dynamic Seal
SECTION "A"
20
27.4
BODY
19
13 13
27.2
19
27.1
20
20
17.1
16
27.1
19
27.2
13
20
17.3
27.3
19
13
13
19
27.5
16
17.1
20
13
19
27.6
27.5
19
27.5
20
27.6
13

5
IOM-DA1
13. Evenly loosen the three cage cap screws
(18) in single revolution increments. If the
regulator contains a lower piston spring (22),
the ITA should rise as the cage cap screws
(18) are evenly backed out. A downwards
holding force should be applied to the top of
the piston-guide bearing (13) to prevent the
ITA from popping up as the last threads of the
cage cap screws (18) are backed out.
14. Remove the ITA by pulling up on the valve
plug (20). Set ITA aside.
15. Remove the lower piston spring (22), as
applicable, from within the body (23). NOTE:
Composition diaphragm constructions do not
normally include a lower piston spring (22); all
metal diaphragm constructions MUST include
a lower piston spring (22).
16. Remove o-ring cage seal (15).
17. If supplied, remove internal sensing drilled
plug (32) using 5/32" (4 mm) Allen wrench.
18. Remove body (23) from vise. Clean all reusable
metal parts according to owner's procedures.
NOTE: On regulators originally supplied as
Special Cleaning Option-55, -56, or -57,
maintenance must include a level of cleanli-
ness equal to Cashco cleaning standards of
#S-1134, #S-1542, #S-1589 respectively.
Contact factory for details.
C. Disassembly of the ITA:
B. Main Valve Disassembly:
WARNING
SYSTEM UNDER PRESSURE. Prior to perform-
ing any maintenance, isolate the regulator from
the system and relieve all pressure. Failure to
do so could result in personal injury.
1. Shut down the system in accordance with
Section VI.
2. Disconnect the external sensing line, if
installed.
3. Though it is possible to disassemble the valve
unit while installed in a pipeline, it is recom-
mended that maintenance be done in a shop
when possible. The description thereafter will
assume shop disassembly. Remove valve
from pipeline.
4. Place the valve unit in a vise with the spring
chamber (4) upwards.
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).
6. Loosen the diaphragm flange bolts (11) and
nuts (12) uniformly.
7. Place matchmarks on body (23) and spring
chamber (4) flanges. Remove the spring
chamber (4).
8. Remove spring follower (5) and range spring
(6).
9. For composition diaphragm construction,
hold the milled “flats” on top of the valve plug
(20) stationary with vise grips. Loosen and
remove the diaphragm lock nut (7). NOTE:
Metal diaphragm constructions do NOT have
a diaphragm lock nut (7).
10. Remove upper diaphragm pressure plate (8).
11. Remove diaphragm(s) (9, 9.1, 9.2, 9.9) and
o-ring upper stem seal (14.1). Examine
diaphragm(s) to determine whether failed; de-
termine if operating conditions are exceeding
pressure, pressure drop or temperature limits.
12. For composition diaphragm construction,
remove lower diaphragm pusher plate (10).
Figure 2: Assembled ITA,
Composition Diaphragm Construction
1. Units with Composition Diaphragm(s) (See
Figure 2):
a. Pull the valve plug (20) downwards and
out of the piston-guide bearing (13) and
out of the cage's (19) bottom, while hold-
ing the cage (19).
b. Remove the piston-guide bearing (13)
from the upper end of the cage (19).
20
14.2 14.3
13
27
15
16
17
19
21
20

IOM-DA16
c. Remove o-ring middle stem seal (14.2)
from piston-guide bearing (13).
d. Examine the components (27.1, 27.2, 27.3,
27.4, 27.5, 27.6) of the dynamic side seal
(27) mechanism to determine if significant
leakage was occurring. If the dynamic
side seal (27) shows signs of significant
leakage, determine if operating conditions
are exceeding pressure, pressure drop, or
temperature limits.
Remove dynamic side seal (27) compo-
nents. Special care should be taken when
using “tools” to remove the components
to ensure that no scratches are imparted
to any portion of the piston-guide bearing
(13) groove.
e. Remove wiper seal (16), if supplied, from
within cage (19).
f. Remove wiper washer (17.1), camber
adjusting washer (17.2), or seal retainer
(17.3), if supplied, from within cage (19).
g. Remove o-ring lower stem seal (14.3) from
plug (20).
h. Remove seat ring (21); examine for signs
of leakage. If seat ring (21) shows signs of
significant leakage, determine if operating
conditions of pressure, pressure drop, or
temperature are exceeding limits.
2. Units with Metal Diaphragm(s) (See Figure 3):
c. Pull the valve plug (20) downwards and
out of the piston-guide bearing (13) and
out of the cage's (19) bottom while holding
the cage (19).
d. Remove the piston-guide bearing (13)
from the upper end of cage (19).
e. Examine the components (27.1, 27.2,
27.3, 27.4, 27.5, 27.6) of the dynamic
side seal (27) mechanism to determine if
significant leakage was occurring. If the
dynamic side seal (27) shows signs of
significant leakage, determine if operat-
ing conditions are exceeding pressure,
pressure drop, or temperature limits.
Remove dynamic side seal (27) compo-
nents and discard. Special care should be
taken when using “tools” to remove the
components to ensure that no scratches
are imparted to any portion of the piston-
guide bearing (13) groove.
f. Remove wiper seal (16), if supplied, from
within cage (19).
g. Remove wiper washer (17.1) or camber
adjusting washer (17.2), if supplied, from
within cage (19).
h. Remove o-ring lower stem seal (14.3)
from plug (20).
i. Remove seat ring (21); examine for signs
of leakage. If seat ring (21) shows signs of
significant leakage, determine if operating
conditions of pressure, pressure drop, or
temperature are exceeding limits.
3. Clean all reusable metal parts according
to owner's procedures. NOTE: On regula-
tors originally supplied as Special Cleaning
Option-55, -56, or -57, maintenance must
include a level of cleanliness equal to Cashco
cleaning standards of #S-1134, #S-1542,
#S-1589 respectively. Contact factory for
details.
D. Inspection of Parts:
1. After inspection remove from the work area
and discard the old “soft goods” parts (i.e.
o-rings, diaphragms, seals, gaskets, etc.) after
inspection. These parts MUST be replaced
with factory supplied new parts.
2. Inspect the metal parts that will be reused. The
parts should be free of surface contaminants,
burrs, oxides, and scale. Rework and clean
the parts as necessary. Surface con
ditions
that affect the regulator performance are stated
below; replace parts that can not be reworked
or cleaned.
Figure 3: Assembled ITA,
Metal Diaphragm Construction
a. To disassemble the ITA, hold the lower
part of the valve plug (20) in a bench vise,
grasping on "flats" directly under seat
disc portion of plug (20). Do not hold on
the machined surface in the plug's (20)
spindle area. (The spindle “slides” in the
pressed-in-place lower guide bushing (24)
and can not be allowed to be marred.)
b. Using a special double-posted spanner
wrench fitting (to order see NOTE in
Section IX, Parts Ordering Information),
turn the piston-guide bearing (13) CCW
to loosen; piston-guide bearing (13) can
be removed by hand after loosening.
"Flats"
13
27
15
17
19
21
20

7
IOM-DA1
3. QC Requirements:
a. Valve plug (20);
1. 16 rms finish on its seating surface
for tight shutoff.
2. No major defects on bottom guide
spindle.
b. Cage (19);
1. 16 rms finish on cylinder bore. No
“ledges” formed due to wear from
moving dynamic side seal (27) or
wiper seal (16).
c. Lower guide bushing (24) (non-replace-
able):
1. 16 rms finish on bore.
2. Max 0.015 inch (0.38 mm) clearance
between valve plug (20) spindle and
lower guide bushing (24).
d. Internal sensing drilled plug (32);
1. Ensure that bore is minimum 0.125
inch (3.20 mm). Drill out as required.
4. Staging Material for Reassembly.
a. Inspect and clean parts, as necessary,
from the spare parts kit. (See Article
VI.A.4. comments concerning cleaning
for oxygen service.)
b. Lay out all the regulator parts and check
against the bill of material.
E. Reassembly of the ITA:
1. When replacing the optional wiper seal (16),
the replacement wiper seal (16) is “pre-
formed”. It will, however, require reforming.
Reform the wiper seal (16) by pressing the
temporary assembly parts into the cage (19)
backwards as shown in Figure 4. The wiper
seal (16) is best left in this position overnight,
but a minimum of two (2) hours prior to reas-
sembly.
2. After forming the wiper seal, remove parts
(13, 16, 17) from cage (19) and disassemble
the temporary assembly of Step 1. above.
3. Installation of dynamic side seal (27) (See
Figure 1):
a. Type OR:
1. Stretch o-ring seal (27.4) over
lower circumference of piston-guide
bearing (13), taking care not to “cut”
o-ring seal (27.4). Using thumbs, work
the o-ring seal (27.4) up and into the
groove of the piston-guide bearing
(13). NOTE: A very slight amount
of fluid and elastomer compatible
lubricant is recommended as an
installation aid.
2. For metal diaphragm construction,
insert camber adjusting washer (17.2)
into cage (19) and allow to rest in the
bottom of the cage (19).
3. Position piston-guide bearing (13)
over upper end of cage (19) prop-
erly oriented. Using thumbs, evenly
press piston-guide bearing (13) into
the cage (19), ensuring not to “cut”
o-ring seal (27.4). Continue press-
ing piston-guide bearing (13) until in
approximate final position.
Figure 4
b. Type CP:
1. Stretch o-ring energizer/seal (27.2)
over lower circumference of piston-
guide bearing (13), taking care not
to “cut” o-ring energizer/seal (27.4).
Using thumbs, work the o-ring en-
ergizer/seal (27.4) up and into the
groove of the piston-guide bearing
(13). NOTE: A very slight amount
of fluid and elastomer compatible
lubricant is recommended as an
installation aid.
2. For metal diaphragm construction,
insert camber adjusting washer (17.2)
into cage (19) and allow to rest in the
bottom of the cage (19).
3. Position TFE cap seal (27.1) ring
with rectangular cross-section at
end of piston-guide bearing (13).
Stretch cap seal (27.1) over lower
end of piston-guide bearing (13) using
thumbs to work the cap seal (27.1)
onto the piston-guide bearing (13).
DO NOT USE A TOOL FOR THIS
STEP. Continue pressing cap seal
(27.1) upwards towards the groove
until the cap seal (27.1) “snaps” into
the groove of the piston-guide bearing
(13).
Not supplied. Use any
bolt, washers (2) and
nut of same approximate
hole size.
17
19
16
13

IOM-DA18
4. Position piston-guide bearing (13)
over and into upper end of cage (19)
until the cap seal (27.1) edge touches
the upper lip of the cage (19). While
gently applying force to press the
piston-guide bushing (13) into the
cage (19), simultaneously use fingers
to lightly press the cap seal (27.1)
inwards into the groove of the piston-
guide bearing (13) until the cap seal
(27.1) “slips into” the cage (19). DO
NOT USE TOOLS, LUBRICANT, OR
HEAVY FORCE TO ENGAGE THE
CAP SEAL (27.1) INTO THE CAGE
(19). Do not press inwards on the Cap
Seal (27.1) too much or the cap seal
(27.1) may slide out of its groove or
the cap seal (27.1) can be damaged.
c. Type CW:
1. Stretch o-ring energizer/seal (27.2)
over lower circumference of piston-
guide bearing (13), taking care not
to “cut” o-ring energizer/seal (27.4).
Using thumbs, work the o-ring en-
ergizer/seal (27.4) up and into the
groove of the piston-guide bearing
(13). NOTE: A very slight amount
of fluid and elastomer compatible
lubricant is recommended as an
installation aid.
2. Place wiper washer (17.1) into “cup”
of Wiper Seal (16). Holding these
parts (17.1 & 16) between thumb and
forefinger, insert into cage (19) at an
approximate 45° angled approach
with wiper washer (17.1) on bottom,
wiper seal (16) on top with turned-
down lip of wiper seal (16) entering
cage (19) first. Rotate wiper seal (16)
and wiper washer (17.1) to a level
position approximately half way down
into cage (19). Allow wiper washer
(17.1) to rest on bottom of cage (19).
3. Position TFE cap seal (27.1) ring
with rectangular cross-section at
end of piston-guide bearing (13).
Stretch cap seal (27.1) over lower
end of piston-guide bearing (13) using
thumbs to work the cap seal (27.1)
onto the piston-guide bearing (13).
DO NOT USE A TOOL FOR THIS
STEP. Continue pressing cap seal
(27.1) upwards towards the groove
until the cap seal (27.1) “snaps” into
the groove of the piston-guide bearing
(13).
4. Position piston-guide bearing (13)
over and into upper end of cage (19)
until the cap seal (27.1) edge touches
the upper lip of the cage (19). While
gently applying force to press the
piston-guide bushing (13) into the
cage (19), simultaneously use fingers
to lightly press the cap seal (27.1)
inwards into the groove of the piston-
guide bearing (13) until the cap seal
(27.1) “slips into” the cage (19). DO
NOT USE TOOLS, LUBRICANT, OR
HEAVY FORCE TO ENGAGE THE
CAP SEAL (27.1) INTO THE CAGE
(19). Do not press inwards on the Cap
Seal (27.1) too much or the cap seal
(27.1) may slide out of its groove or
the cap seal (27.1) can be damaged.
d. Type PR:
1. Stretch corrugated metal piston ring
energizer (27.6) over lower circumfer-
ence of piston-guide bearing (13).
Using thumbs work the energizer
(27.6) into the piston-guide bearing
(13) groove.
2. Spread a piston ring seal (27.5) and
slide over lower circumference of
piston-guide bearing (13), taking care
not to “cut” piston ring seal (27.5).
Using thumbs, work the piston ring
seal (27.5) into the groove of the
piston-guide bearing (13). Repeat
this procedure with a second piston
ring seal (27.5). NOTE: A piston ring
assembly (PRA) consists of one metal
corrugated energizer (27.6) and two
piston ring seals (27.5). Also, the 6"
body size includes three sets of PRA's
in the sets of grooves; all other body
sizes have only one set of PRA.
3. Position piston-guide bearing (13)
over and into upper end of cage (19)
until the lower piston ring seal (27.5)
touches the upper lip of the cage (19).
While gently applying force to press
the piston-guide bearing (13) into the
cage (19), simultaneously use fin-
gers to lightly circumferentially press
the first (lower) piston ring seal (27.5)
inwards into the piston-guide bearing
(13) groove until the first piston ring
seal (27.5) “slips into” the cage (19).
Repeat for the second piston ring seal
(27.5).

9
IOM-DA1
e. Type PW:
1. Place wiper washer (17.1) into “cup”
of Wiper Seal (16). Holding these
parts (17.1 & 16) between thumb and
forefinger, insert into cage (19) at an
approximate 45° angled approach
with wiper washer (17.1) on bottom,
wiper seal (16) on top with turned-
down lip of wiper seal (16) entering
cage (19) first. Rotate wiper seal (16)
and wiper washer (17.1) to a level
position approximately half way down
into cage (19). Allow wiper washer
(17.1) to rest on bottom of cage (19).
2. Stretch corrugated metal piston ring
energizer (27.6) over lower circumfer-
ence of piston-guide bearing (13).
Using thumbs work the energizer
(27.6) into the piston-guide bearing
(13) groove.
3. Spread a piston ring seal (27.5) and
slide over lower circumference of
piston-guide bearing (13), taking care
not to “cut” piston ring seal (27.5).
Using thumbs, work the piston ring
seal (27.5) into the groove of the
piston-guide bearing (13). Repeat
this procedure with a second piston
ring seal (27.5). NOTE: A piston ring
assembly (PRA) consists of one metal
corrugated energizer (27.6) and two
piston ring seals (27.5).
4. Position piston-guide bearing (13)
over and into upper end of cage (19)
until the lower piston ring seal (27.5)
touches the upper lip of the cage (19).
While gently applying force to press
the piston-guide bearing (13) into the
cage (19), simultaneously use fingers
to lightly circumferentially press the
first (lower) piston ring seal (27.5)
inwards into the piston-guide bearing
(13) groove until the first piston ring
seal (27.5) “slips into” the cage (19).
Repeat for the second piston ring seal
(27.5).
f. Type UC:
1. Position u-cup seal (27.3) over
lower circumference of piston-guide
bearing (13). Ensure that the u-cup
seal (27.3) is oriented with the center-
open-downwards as shown in Figure
1, as the u-cup seal (27.3) depends
upon the P1-Inlet Pressure to pres-
sure activate the seal for proper seal-
ing action.
2. Position piston-guide bearing (13)
over and into upper end of cage (19)
until the cap seal (27.1) edge touches
the upper lip of the cage (19). While
gently applying force to press the
piston-guide bearing (13) into the
cage (19), simultaneously use fingers
to lightly press the u-cup seal (27.3)
inwards into the groove of the piston-
guide bearing (13) until the u-cup seal
(27.3) “slips into” the cage (19). DO
NOT USE TOOLS, LUBRICANT, OR
HEAVY FORCE TO ENGAGE THE
U-CUP SEAL (27.3) INTO THE CAGE
(19).
4. Place properly oriented seat ring (21) onto its
shoulder at the lower end of cage (19).
5. Composition Diaphragm Designs.
a. Place new o-ring lower stem seal (14.3)
into groove of valve plug (20).
b. Insert valve plug (20) upwards through
lower end of cage (19) and through the
center hole in piston-guide bearing (13),
also capturing camber adjusting washer
(17.2), wiper washer (17.1) and wiper seal
(16), if supplied. Hold plug (20) and cage
(19) together.
c. Place an oversized nut or stack of wash-
ers, the same approximate height of the
upper diaphragm pressure plate (8) and
the lower diaphragm pusher plate (10),
over the upper end of valve plug (20) and
temporarily secure with diaphragm lock
nut (7), manually tightened. DO NOT AL-
LOW PLUG (20) TO ROTATE AGAINST
SEAT RING (21) DURING TIGHTENING.
d. This completes ITA preliminary/partial
reassembly.
6. Metal Diaphragm Designs.
a. Insert valve plug (20) upwards through
lower end of cage (19) and through the
center hole of camber adjusting washer
(17.2) or wiper washer (17.1) and wiper
seal (16).
b. Engage valve plug (20) with piston-guide
bearing (13) threads and tighten manually
as far as possible.
c. Place ITA into a vise with leaded jaws
and grasp at a hub location on the valve
plug (20) that is not in the “spindle” zone.
(See Figure 3.)
d. Using a special double-posted spanner
wrench fitting (to order see NOTE in
Section IX, Parts Ordering Information),
tighten the piston-guide bearing (13) to the
valve plug (20) with the following torque
values. DO NOT ALLOW PLUG (20) TO
ROTATE AGAINST SEAT RING (21)

IOM-DA110
DURING TIGHTENING. TFE-HK-HK-TFE-TFE, beginning with
lower wetted diaphragm (9) first.
g. Place upper diaphragm pressure plate
(8) over upper end of valve plug (20) with
tongue and groove “ridge” on lower side.
h. Place lubricant on valve plug (20) threaded
end. Engage diaphragm lock nut (7) with
upper end of valve stem (20) as far as
possible manually.
i. Place a wrench on diaphragm lock nut (7)
and a torque wrench on the upper end
of valve plug (20). Hold torque wrench
stationary and rotate diaphragm lock nut
(7) to the following torque values:
DO NOT allow valve plug (20) to rotate against
seat ring (21) during tightening.
j. This completes ITA reassembly.
8. Units with V-TFE & CTFE seat ring (21): Due
to the relative "hardness" of the V-TFE & CTFE
material, to obtain the best possible shutoff
it is necessary to "coin" the V-TFE & CTFE
with a permanent indentation.
a. Close-off the outlet connection.
b. The level of seat leakage can be
quantified at the internal sensing drilled
plug (32) for internal sensing units. For
external sensing units, it will be necessary
to remove the internal sensing plug (33).
c. Place 50 psig (3.5 Barg) of gas pressure
to the valve's inlet.
d. Using a soft-headed mallet (rubber,
leather), sharply rap the top end of the
plug (20) for composition diaphragm de-
signs, or the piston-guide bearing (13) for
metal diaphragm designs. (Note: Gas will
escape as the plug (20) opens at the seat
ring (21). Allow sufficient time for leak-
age pressure on outlet to bleed-off.) The
ham-mer rap should be strong enough to
"bounce" the plug (20) into the seat ring
(21), leaving the "coined" indentation.
e. Repeat d. a minimum of 2 times until the
best possible seat leakage is obtained.
f. After "coining" completed, remove gas
pressure source, remove outlet closure,
and reinstall plug (33) if removed.
9. Metal Diaphragm Designs:
a. Install new diaphragm gasket (37) onto
body (23) diaphragm flange.
b. Position diaphragm(s) (9) onto body's (23)
diaphragm flange with bolt holes aligned.
e. This completes ITA reassembly.
F. Main Reassembly:
1. Place body (23) in a vise.
2. Reinstall internal sensing drilled plug (32) with
compatible thread sealant.
3. Insert the lower piston spring (22) into the
body (23), if supplied.
4. Fit the o-ring cage seal (15) into its body (23)
groove.
5. With the ITA held manually in the closed posi-
tion, insert ITA into body (23).
6. Properly align all three cage bolt (18) holes
as there is only one circumferential location
possible for this alignment. If a lower piston
spring (22) is used, apply downward force to
the top of the cage (19) until the ITA is lowered
sufficiently to engage the cage bolts (18) into
the body (23). Engage all of the cage bolts
(18), then evenly screw in the cage bolts in
one-half revolution increments to pull down
the ITA, taking care NOT TO “COCK” THE
ITA IN THE BODY. Torque the cage bolts
(18) to 13-15 ft-lbs (18-20 N-m).
7. Composition Diaphragm Designs:
a. For the following steps b.–h., the upper
end of valve plug (20) MUST be manually
held up if unit is not supplied with lower
piston spring (22).
b. Remove temporarily installed diaphragm
lock nut (7) and spacers of previous Step
5.c. this section.
c. Place new o-ring middle stem seal (14.2)
into groove of piston-guide bearing (13)
upper surface.
d. Position lower diaphragm pusher plate
(10) over upper end of valve plug (20)
with tongue and groove on upper side.
e. Place new o-ring upper stem seal (14.1)
over upper end of valve plug (20).
f. Place diaphragm(s) (9) over end of valve
plug (20). NOTE: For multiple diaphragms
(9) that include TFE material, the TFE
should be on wetted side; for 6-ply TFE
elastomer diaphragm (9), stackup is TFE-
Recommended Torque Values are:
Body Size Torque
in. (mm) ft-lbs (Nm)
1/2"-1" (DN15-25) 30-50 (41-68)
1 1/4"-2" (DN32-50) 45-70 (61-95)
Body Size Torque
in (mm) ft-lbs. (Nm)
1/2"-1" (DN15-25) 60-70 (81-95)
1 1/4"- 2" (DN32-50) 120-130 (163-176)
2 1/2" - 4" (DN65-100) 180-200 (244-271)

11
IOM-DA1
c. Position upper diaphragm pressure plate
(8) onto center top of diaphragm(s) (9)
with hub upwards.
10. Place a small amount of heavy grease into
the adjusting screw (1) threaded opening of
spring chamber (4). Reengage both adjust-
ing screw (1) and its lock nut (2) with spring
chamber (4). Allow end of adjusting screw to
protrude into interior approximately 1/2 inch
(12 mm).
11. Place range spring (6) centered on upper
diaphragm pressure plate (8).
12. Place a dab of heavy grease in the recess of
the spring follower (5). Place spring follower
on upper end of range spring (6).
13. Aligning matchmarks and bolt holes, place
spring chamber (4) over range spring (6). If
spring chamber (4) flange reaches body (23)
flange without a gap, remove and lower ad-
justing screw (1) deeper into spring chamber
(4) cavity another 1/4 inch. Repeat this pro-
cedure until the adjusting screw (1) keeps the
two flanges form touching by approximately
1/8 inch (3 mm). NOTE: For metal diaphragm
construction, if flanges do not come together
equally, the upper diaphragm pressure plate
(8) may be off-center. Remove spring chamber
(4) and reposition upper diaphragm pressure
plate (8) until the spring chamber (4) comes
down evenly on all sides.
14. Reinstall all flange bolts (11) and nuts (12)
with nameplate (99) located under one bolt
head. Hand-tighten nuts (12).
NOTE: If a six-ply diaphragm is being used,
it is important that the diaphragm (9) is “pre-
formed” – pulled together to remove as much
entrapped air as possible and allow formation
of a diaphragm (9) convolution. Starting with
the body bolts and nuts (11,12) hand tightened,
“preforming” can be accomplished by any one
of the following techniques:
a. Relax range spring fully by rotating
adjusting screw CCW.
b. Apply 30 psig (2.1 Barg) pressure to the
valve outlet.
OR
Block the valve outlet and apply 30 psig
(2.1 Barg) under the diaphragm through
the 1/4" NPT (plugged) external pres-
sure sensing connection on the valve
diaphragm flange.
c. Leave pressure on through tightening
of bolting (11,12).
15. Evenly tighten the body bolting (11,12) in an
alternating cross pattern in one revolution
increments to the following torque value:
If supplied, remove pressure of previous
Step 14.
G. Units with Supported Diaphragm Designs:
1. A supported diaphragm (9) construction is
designated as Opt-80 High Outlet Pressure.
2. For a Model DA1 the only “special” part to be
supplied is the spring chamber (4). This spring
chamber (4) includes a machined ledge to
support the diaphragm upon overpressure,
and prevent a bust.
H. Converting Internal/External Sensing:
1. Disassemble the regulator and remove the
diaphragm(s) (9) according to Steps 1-12 in
Part B – Main Regulator Disassembly.
2. To convert from internal to external sensing,
remove the drilled pipe plug (32) and install a
solid pipe plug. Reverse this step for convert-
ing from external to internal sensing.
3. Reassemble the regulator according to Part
F – Main Regulator Reassembly.
I. Pressure Testing:
1. If a hydrostatic pressure test is performed,
pressure must be applied uniformly throughout
the regulator. In particular apply the same
pressure to body inlet, body outlet, and spring
chamber.
DO NOT HYDROSTATICALLY TEST WITH-
OUT SPRING CHAMBER PRESSURIZED.
NOT ADHERING WILL DO PHYSICAL IN-
TERNALS DAMAGE THAT COULD RENDER
THE UNIT INOPERABLE.
2. Inboard Leakage Test.
a. Release all range spring force by backing
out adjusting screw fully.
b. Pressurize inlet to 30 psig (2.1 Barg) with
air, GN2.
c. Tube outlet to a beaker of water to observe
number of escaping gas bubbles.
3. Pressure Containment Test.
Body Size Torque
in (mm) ft-lbs. (Nm)
1/2"-2" (DN15-50) 30-35 (41-47)
2 1/2"-4" (DN65-100) 45-50 (61-69)

IOM-DA112
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 process
may be causing difficulties.
The key to efficient 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
conditions.
It is imperative the following information be provided by the customer:
Fluid (with fluid properties)
Range of flow rate
Range of inlet pressure
Range of outlet pressure
Range of fluid temperature
Range 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.
2. Erratic regulation, instability or hunting (liquid service).
a. Pressurize inlet and outlet to 1.0 x Upper
Value of Range Spring or 30 psig (2.1
Barg) with air or GN2, whichever is higher.
b. Soap solution test all external leak points;
plugged connections, diaphragm flange,
diaphragm bolting and spring chamber
vent opening.
4. 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.
Possible Causes Remedies
A. Sticking of internal parts A. Remove internals, clean and if necessary, replace.
B. Load changes are too quick for system. B. Convert to external sensing (if necessary) and install an orifice or
needle valve in external sensing line.
C. Oversized regulator C. Check actual flow conditions; resize regulator for minimum and
maximum flow; if necessary, replace with smaller regulator.
Possible Causes Remedies
A. Air trapped under diaphragm. A. Install valve on external sensing port and bleed off air. (Install regu-
lator upside down to help prevent reoccurrence.)

13
IOM-DA1
3. Downstream pressure will not reach desired setting.
4. Diaphragm continually breaks (steam service regulators).
5. Diaphragm continually breaks (all regulators).
6. Leakage at diaphragm flange.
7. Leakage across seat.
Possible Causes Remedies
A. Stem seals (14) which protect fluorocarbon elastomer
in diaphragm assembly may have deteriorated. A. Replace with new stem seals (14).
B. Diaphragm nut (7) may not be torqued to proper value. B. Confirm torque value in accordance with Section
VI paragraph F-7.
C. Diaphragm too stiff causing it to crack in service.
C. Follow proper preforming and air evacuation tech
niques during diaphragm installation in accordance
with Section VI, paragraph F-13.
Possible Causes Remedies
A. Supply pressure is down (confirm on pressure gauge.) A. Increase supply pressure.
B. Undersized regulator.
B. Check actual flow conditions; resize regulator for
minimum and maximum flow; if necessary, replace
with larger regulator.
Possible Causes Remedies
A. Differential pressure across diaphragm may have
exceeded limits. (See Table 4 in Tech Bulletin DA1-TB.
A. Be aware of limits as well as where the various
pressures are acting. Install pressure safety equip-
ment as necessary.
Possible Causes Remedies
A. Body bolts not torqued properly. A. Torque to proper value (see Section VI, paragraph
F-14)
B. Pressure at diaphragm may be too high for regulator
design. B. Consult factory.
Possible Causes Remedies
A. Contamination (debris) in regulator.
A1. Remove internals, clean, and if necessary,
replace sealing and seating elements.*
A2. "Coin" seat if V-TFE or CTFE seat material.
B. Oversized regulator; valve plug operates directly next
to seat.
B. Check actual flow conditions; resize regulator for
minimum and maximum flow; if necessary, replace
with smaller regulator.
*Excess seat leakage may be diagnosed when a failure of the dynamic side seal has occurred. Inspect both poten-
tial internal leak paths.

IOM-DA114
Figure 5: Location of Auxiliary Ports
2
1
7
5
NEW REPLACEMENT UNIT:
Contact your local Cashco, Inc., Sales Represen-
tative 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.
–7–
IX. ORDERING INFORMATION
NEW REPLACEMENT UNIT vs PARTS "KIT" FOR FIELD REPAIR
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 reflects revision level for the product).
PARTS "KIT" for FIELD REPAIR:
Contact your local Cashco, Inc., Sales Represen-
tative 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” reflect 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".
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.
SECTION IX
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 specifications 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.
If the "BOM" is not available, refer to the cross-
sectional drawings included in this manual for
part identification and selection.
A Local Sales Representative will provide
quotation for appropriate Kit Number, Price
and Availability.

15
IOM-DA1
Item No. Description
1 Adjusting Screw
2 Adjusting Screw Lock Nut
4 Spring Chamber
5 Spring Follower (Button)
6 Range Spring
7 Diaphragm Lock Nut
8 Upper Diaphragm Pressure Plate
9 ‡‡ Diaphragm
9.1 Diaphragm (Material #1)
9.2 Diaphragm (Material #2)
9.9 Diaphragm TFE Cover
10 Lower Diaphragm Pusher Plate
11 Flange Bolts
* 12 Flange Bolt Nuts
13 Piston-Guide Bearing
14 ‡‡ Stem Seals
14.1 Upper Stem Seal
14.2 Middle Stem Seal
14.3 Lower Stem Seal
15 ‡‡ Cage Seal
16 Wiper Seal
‡‡ Recommended Repair Parts
Item No. Description
17.1 Wiper Washer
18 Cage Cap Screws
19 Cage
20 Valve Plug
21 ‡‡ Seat Ring
22 Lower Piston Spring (if supplied)
23 Body
24 Lower Guide Bushing
26 Tap Plug (Not Shown)
** 27 ‡‡ Dynamic Side Seal
27.1 TFE Cap Seal
27.2 O-ring Energizer/Seal
27.3 U-cup with Metal Energizer
27.4 O-ring Seal
27.5 Piston Ring Seal
27.6 Piston Ring Energizer
32 Internal Sensing Plug (External Sensing Only)
33 Internal Sensing Drilled Plug (Internal
Sensing Only)
* Not required on 2" CS & SST Body Material.
** Reference Figure 1 for details of Item #27 - Dynamic Side Seal
Not Shown:
Item 66. Lays flat on top of item 8, only used when I.D. of spring, item 6,
is too small to slip over item 7.
Model DA1
Composition Diaphragm
(w/Wiper Seal)
24
20
21
19
14.2
18
14.1
10
9
8
7
2
4
1
5
6
13
11
32 33
12
15
27
16
17.1
14.3
23

IOM-DA116
Item No. Description
1 Adjusting Screw
2 Adjusting Screw Lock Nut
4 Spring Chamber
5 Spring Follower (Button)
6 Range Spring
8 Upper Diaphragm Pressure Plate
9 ‡‡ Diaphragm
11 Flange Bolts
* 12 Flange Bolt Nuts
13 Piston-Guide Bearing
15 ‡‡ Cage Seal
17.2 Camber Adjusting Washer
18 Cage Cap Screws
19 Cage
20 Valve Plug
21 ‡‡ Seat Ring
Item No. Description
22 Lower Piston Spring
23 Body
24 Lower Guide Bushing
26 Tap Plug (Not Shown)
** 27 ‡‡ Dynamic Side Seal
27.1 TFE Cap Seal
27.2 O-ring Energizer/Seal
27.3 U-cup with Metal Energizer
27.4 O-ring Seal
27.5 Piston Ring Seal
27.6 Piston Ring Energizer
32 Internal Sensing Plug (External Sensing Only)
33 Internal Sensing Drilled Plug (Internal
Sensing Only)
37 Diaphragm Gasket
* Not required on 2" CS & SST Body Material.
** Reference Figure 1 for details of Item #27 - Dynamic Side Seal
‡‡ Recommended Repair Parts
Model DA1
Metal Diaphragm
(wo/Wiper Seal)
24
23
22
21
19
15
18
12
37
9
8
6
5
21
4
11
13
32 33
27
17.2
20

17
IOM-DA1
ATEX 94/9/EC: Explosive Atmospheres and Cashco Inc. Regulators
These valves satisfy the safety conditions according to EN 13463-1 and EN 13463-5 for equipment group IIG 2 c.
Caution: Because the actual maximum temperature depends not on the equipment itself, but upon the fluid temperature, a
single temperature class or temperature cannot be marked by the manufacturer.
Specific Precaution to Installer: Electrical grounding of valve must occur to minimize risk of effective electrical discharges.
Specific Precaution to Installer: Atmosphere vent holes should be plugged to further minimize the risk of explosion.
Specific Precaution to Maintenance: The Valve Body/ Housing must be regularly cleaned to prevent buildup of dust deposits.
Specific Precaution to Maintenance: Conduct periodic Continuity Check between Valve Body/ Housing and Tank to minimize
risk of electrical discharges.
Attention: When repairing or altering explosion-protected equipment, national regulations must be adhered to. For maintenance
and repairs involving parts, use only manufacturer's original parts.
ATEX requires that all components and equipment be evaluated. Cashco pressure regulators are considered components.
Based on the ATEX Directive, Cashco considers the location where the pressure regulators are installed to be classified
Equipment-group II, Category 3 because flammable gases would only be present for a short period of time in the event of a leak.
It is possible that the location could be classified Equipment-group II, Category 2 if a leak is likely to occur. Please note that the
system owner, not Cashco, is responsible for determining the classification of a particular installation.
Product Assessment
Cashco performed a conformity assessment and risk analysis of its pressure regulator and control valve models and their
common options, with respect to the Essential Health and Safety Requirements in Annex II of the ATEX directive. The details
of the assessment in terms of the individual Essential Health and Safety Requirements, are listed in Table 1. Table 2 lists all of
the models and options that were evaluated and along with their evaluation.
Models and options not listed in Table 2 should be assumed to not have been evaluated and therefore should not be selected
for use in a potentially explosive environment until they have been evaluated.
Standard default options for each listed model were evaluated even if they were not explicitly listed as a separate option in the
table. Not all options listed in the tables are available to all models listed in the tables. Individual TB’s must be referenced for
actual options.
When specifying a regulator that is to be used in a potentially explosive environment one must review the evaluations in Table 1
and 2 for the specific model and each and every option that is being specified, in order to determine the complete assessment
for the unit.
A summary of the models and options found to have an impact on ATEX assessment due to potential ignition sources or other
concerns from the ATEX Essential Health and Safety Requirements, are listed below.
1. The plastic knob used as standard on some models, (P1, P2, P3, P4, P5, P7, 3381, 4381, 1171, and 2171) is a
potential ignition source due to static electricity. To demonstrate otherwise, the knob must be tested to determine
if a transferred charge is below the acceptable values in IEC 60079-0 Section 26.14 (See items 25, 27, and 28 in
Appendix A). Until the plastic knob has been shown to be acceptable, then either the metal knob option, or a preset
outlet pressure option is required to eliminate this ignition source (See items 45 and 64 in Tables).
2. The pressure gauges offered as options on a few of the regulator models (DA’s, P1-7, D, 764, 521), use a plastic
polycarbonate window that is a potential ignition source due to static electricity. To demonstrate that the gauges are
not a potential source of ignition, the gauges would need to be tested to determine if a transferred charge is below
NOTICE
Only for Product Codes wherein hazard
category ATEX has been selected.

IOM-DA118
Cashco, Inc.
P.O. Box 6
Ellsworth, KS 67439-0006
PH [phone]
Fax. # [phone]
www.cashco.com
email: [email protected]
Printed in U.S.A. DA1-IOM
Cashco do Brasil, Ltda.
Al.Venus, 340
Indaiatuba - Sao Paulo, Brazil
PH [phone]
Fax. No.
www.cashco.com
email: [email protected]
Cashco GmbH
Handwerkerstrasse 15
15366 Hoppegarten, Germany
PH [phone]
Fax. No. [phone]
www.cashco.com
email: [email protected]
indicating the gauge is compliant with the ATEX Directive (See items 26, 27, and 28 in Appendix A). Until compliance
is determined, regulators should not be ordered with pressure gauges for use in potentially explosive environments.
3. Tied diaphragm regulators with outlet ranges greater than 100 psig should be preset to minimize the risk that improper
operation might lead to an outboard leak and a potentially explosive atmosphere (See item 6 in Table 1).
4. Regulators must be ordered with the non-relieving option (instead of the self-relieving option) if the process gas they are
to be used with is hazardous (flammable, toxic, etc.). The self-relieving option vents process gas through the regulator
cap directly into the atmosphere while the non-relieving option does not. Using regulator with the self- relieving option
in a flammable gas system could create an explosive atmosphere in the vicinity of the regulator.
5. Regulators with customer supplied parts are to be assumed to not have been evaluated with regard to ATEX and thus
are not to be used in a potentially explosive environment unless a documented evaluation for the specific customer
supplied parts in question has been made. Refer to Table 1 for all models and options that have been evaluated.
Product Usage
A summary of ATEX related usage issues that were found in the assessment are listed below.
1. Pressure regulators and control valves must be grounded (earthed) to prevent static charge build-up due to the flowing
media. The regulator can be grounded through any mounting holes on the body with metal to metal contact or the
system piping can be grounded and electrical continuity verified through the body metal seal connections. Grounding
of the regulator should follow the same requirements for the piping system. Also see item 30 in Table 1.
2. The system designer and users must take precautions to prevent rapid system pressurization which may raise surface
temperatures of system components and tubing due to adiabatic compression of the system gas.
3. Heating systems installed by the user could possibly increase the surface temperature and must be evaluated by the
user for compliance with the ATEX Directive. User installation of heating systems applied to the regulator body or
system piping that affects the surface temperature of the pressure regulator is outside the scope of this declaration and
is the responsibility of the user.
4. The Joule-Thomson effect may cause process gases to rise in temperature as they expand going through a regulator.
This could raise the external surface temperature of the regulator body and downstream piping creating a potential
source of ignition. Whether the Joule-Thomson effect leads to heating or cooling of the process gas depends on
the process gas and the inlet and outlet pressures. The system designer is responsible for determining whether the
process gas temperature may rise under any operating conditions. If a process gas temperature rise is possible under
operating conditions, then the system designer must investigate whether the regulator body and downstream piping
may increase in temperature enough to create a potential source of ignition.
The process gas expansion is typically modeled as a constant enthalpy throttling process for determining the temperature change.
A Mollier diagram (Pressure – Enthalpy diagram with constant temperature, density, & entropy contours) or a Temperature –
Entropy diagram with constant enthalpy lines, for the process gas, can be used to determine the temperature change. Helium
and hydrogen are two gases that typically increase in temperature when expanding across a regulator. Other gases may
increase in temperature at sufficiently high pressures.
Product Declaration
If the above issues are addressed by selecting options that do not have potential sources of ignition, avoiding options that
have not been assessed, and by taking the proper usage issue precautions, then Cashco regulators can be considered to be a
mechanical device that does not have its own source of ignition and thus falls outside the scope of the ATEX directive.