Cashco P4 User Manual

INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM)

MODEL P4

BALANCED PRESSURE REDUCING REGULATOR

SECTION I

I. DESCRIPTION AND SCOPE

The Model P4 is a high fl ow single stage pressure reducing regulator used to control downstream (outlet or P2 )
pressure. Sizes are 3/8" and 1/2" (DN10 and DN15) FNPT or 1/2" (DN15) with Tri-Clamp connections. The unit is
suitable for gaseous service. Refer to Technical Bulletin P4-TB for design conditions and selection recommendations.

SECTION II

IOM-P4

11/13

II. INSTALLATION

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.

1. An inlet block valve should always be installed.

2. If service application is continuous such that
shut down is not readily accomplished, it is rec­ommended that an inlet block valve, outlet block
valve, and a manual bypass valve be installed.

3. Pipe unions should be installed to allow removal
from piping.

4. An outlet pressure gauge should be located ap­ proxi mately ten pipe diameters downstream, and
within sight.

5. All installations should include a downstream re­ lief de vice if the inlet pressure could exceed the
pres sure rating of any downstream equip ment or
the maximum outlet pressure rating of the unit.

Supply

@P

1

Blowdown-Drain

SRV

Model P4
Reducing
Regulator

Recommended Piping Schematic

For Pressure Reducing Station

Bypass

Blowdown-Drain

Outlet

@P

2

7. In plac ing thread seal ant on pipe ends pri or to
en gage ment, ensure that excess material is
re moved and not allowed to enter the regulator
upon startup.

8. Flow Direction: Install so the fl ow direction match-
es the inlet stamp on the main regulator body (1).

9. For best performance, install in well drained hori­ zon tal pipe.

10. Basic Regulator - (Refer to Figure 2): Regula­tor may be rotated around the pipe axis 360°.
Recommended position is with knob (4) ver ti cal
upwards.

P

1

6. Clean the pip ing of all foreign material including
chips, welding scale, oil, grease and dirt before
installing the reg u la tor. Strainers are rec om­ mend ed.

11. Regulators are not to be buried un der ground.

12. For insulated piping systems, recommendation is
to not insulate regulator.

SECTION III

III. PRINCIPLE OF OPERATION

1. Movement occurs as pressure variations register
on the diaphragm (7.1). The registering pressure
is the outlet, P2, or downstream pressure. The
range spring (15) opposes diaphragm move­ ment. As outlet pressure drops, the range spring

SECTION IV

IV. STARTUP

CAUTION

The maximum outlet pressure is stamped on the body
as the upper range spring pres sure level, and is the
rec om mend ed “upper operative limit” for the sens ing
diaphragm (see Sec tion IV. Startup, Step 7). Higher
press ures could dam age the di a phragm. (Field hy­dro static tests fre quent ly de stroy di a phragms. DO
NOT HYDRO STATIC TEST THRU AN IN STALLED
UNIT; ISO LATE FROM TEST.)

1. Start with the block valves closed. A by pass
valve may be used to maintain out let pres sure
in the down stream sys tem without changing the
fol low ing steps.

2. Relax the range spring (15) by turning knob (4)
counter clockwise (CCW) until ro ta tion comes to
a complete stop.

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) pres sure via gauge to ensure not
over-pressurizing. NOTE: If no bypass valve is

in stalled, extra caution should be used in starting
up a cold system; i.e. do everything slowly.

4. Crack open the outlet (downstream) block
valve.

push es the diaphragm down, opening the port; as
outlet pres sure in creas es, the diaphragm push es
up and the port opening clos es.

2. A complete diaphrag failure will cause the reg u la­ tor to fail open.

5. Slowly open the inlet (upstream) block valve ob­ serv ing the outlet (downstream) pressure gauge.
De ter mine if the regulator is fl owing. If not, slowly
rotate knob (4) clock wise (CW) until fl ow 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 pres sure,
close the block valve and go to Step 2, then return
to Step 4.

8. When fl ow is established steady enough that the
outlet (downstream) block valve is fully open, be­ gin 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
turning knob (4) CW to increase outlet pressure,
or CCW to reduce outlet pressure.

10. Reduce system fl ow to a minimum level and ob-
serve 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 up per limit of the range spring by greater
than 10%. Example with 2-100 psig (.14-6.9 Barg)
range spring at low fl ow the outlet pressure should
not exceed 110 psig (7.6 Barg), if it does, con sult
factory).

V. SHUTDOWN

1. On systems with a bypass valve, and where sys­ tem pressure is to be main tained as the reg u la tor
is shut down, slowly open the bypass valve while
closing the inlet (up stream) block valve. Fully
close the inlet (up stream) block valve. (When on
bypass, the sys tem pres sure must be con stant ly
observed and man u al ly reg u lat
outlet (down stream) block valve.

2

ed. Close the

SECTION V

CAUTION

Do not walk away and leave a bypassed
regulator unattended.

2. If the regulator and system are to both be shut
down, slowly close the inlet (upstream) block
valve. Close the outlet (downstream) valve only
if reg u la tor re mov al is required.

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VI. MAINTENANCE

WARNING

SYSTEM UN DER PRES SURE. Prior to per form ing
any maintenance, isolate the reg u la tor from the
sys tem and relieve all pres sure. Failure to do so
could result in personal injury.

A. General:

SECTION VI

Figure 1: Diaphragm Subassembly

1. Maintenance procedures hereinafter are
based upon re mov al of the regulator unit from
the pipeline where in stalled.

2. Owner should refer to owner's procedures for
removal, handling, cleaning and disposal of
non reuseable parts, i.e. gaskets, etc.

3. Refer to Figure 2 for basic reg u la tor and Fig­ure 1 for the diaphragm sub as sem bly.

B. Diaphragm Replacement:

CAUTION

To prevent damage to body, use soft jaws when

placing body in a vise. Position so that vise closes
over the fl ats on lower end of body.

1. Securely install the body (1) in a vise with
knob (4) directed upwards.

5

WARNING

SPRING UNDER COMPRESSION. Prior to re mov­ ing spring chamber, relieve range spring com pres­ sion by turn ing knob CCW until ro ta tion comes to a
com plete stop. Fail ure to so so may result in fl ying
parts that could cause personal injury.

2. Relax range spring (15) by turning knob (4)
CCW until rotation comes to a complete stop.
NOTE: It is not necessary to remove the knob
before removing the spring chamber (6) from
the body (1).

5. Remove actuator nut (7.3) and separate all
parts of the diaphragm subassembly (7).

6. Clean body (1) diaphragm fl ange surface
and all re us able parts according to owner's
procedures. Do not scratch di a phragm

gas ket seat ing sur face. NOTE: On reg u-
la tors origi nally sup plied as “oxygen clean”,
Option-M, main tenance must in clude a level
of clean li ness equal to Cash co's clean ing
stan dard #S-1134. On regulators originally
suppled for Sanitary Service, maintenance
must in clude a level of clean li ness equal to
Cash co clean ing stan dard #S-1576. Contact
factory for details.

7. Inspect and replace any necessary parts.

NOTE: Use only parts man u fac tured and
sup plied by Cashco, Inc. for these products.
See Section VIII.

8. Reassemble di a phragm subassembly (7) by
plac ing the actuator gasket (7.4), di a phragm
(7.1), and actuator o-ring (7.5) over the
threads of the actuator post (7.2). Place a
thread sealant com pound on the threads of
the ac tu a tor post (7.2) prior to installing the
actuator nut (7.3). Install ac tu a tor nut (7.3)
and tighten to the fol low ing torque value: 15
Ft-lbs (20 Nm).

9. Place the diaphragm gas ket (10) onto the
body (1) diaphragm fl ange. Place di a phragm
subassembly (7) on top of the gasket (10).

IOM-P4

3. Remove spring chamber (6) by grasping the

fl ats and turning CCW. Upon removal, the
range spring (15), range spring clip (16), and
spring button (5) should remain inside the
spring cham ber subassembly.

4. Remove diaphragm subassembly (7) con sist ­ing of the actuator nut (7.3), diaphragm (7.1),
ac tu a tor post (7.2), ac tu a tor gasket (7.4),
ac tu a tor o-ring (7.5). Remove di a phragm
gas ket (10).

10. Lubricate the threads of the body (1) with
a light weight grease that is compatible with
service use. Ro tate the spring chamber (6)
CW by hand onto the threaded portion of
the body (1) until fi rmly seated against the
diaphragm gasket (10). Tighten to the fol low­ ing torque val ue: 65–70 Ft lbs (88–95 Nm).

11. Pressurize with air and spray liquid leak de­ tec tor around body (1) and spring chamber
(6) to test for leakage. En sure that an outlet
pres sure is main tained during this leak test

3

of at least mid-range spring level; i.e. 2-100
psig (.14-6.9 Barg) range spring, 51 psig
(3.5 Barg) test pres sure min i mum.

C. Trim Replacement:

1. Remove spring chamber (6) and diaphragm
subassembly (7) per Section VI, Steps B.1.–
B.4.

2. Remove seat retainer (13) by turning CCW.

3. Remove poppet (8) and poppet spring (9).

4. Remove o-ring (11) and back-up ring (17).

5. Clean debris from within the body (1) cav­ity. Clean all parts to be reused according
to own er's pro ce dures. NOTE: On reg u la-

tors origi nally sup plied as “oxygen clean”,
Option-M, main tenance must in clude a level
of clean li ness equal to Cash co's clean ing
stan dard #S-1134. On regulators originally
suppled for Sanitary Service, maintenance
must in clude a level of clean li ness equal to
Cash co clean ing stan dard #S-1576. Contact
factory for de tails.

6. Inspect all parts for damage and replace if
necessary. NOTE: Use only parts man u fac-

tured and supplied by Cashco, Inc. for these
products. See Section VIII.

7. Place poppet spring (9) into body (1) cavity.

8. Place new o-ring (11) and back-up ring (17)
onto poppet (8).

9. Place poppet (8) inside the poppet spring (9).
The angled seating surface of the poppet
must face up toward the seat (12).

10. Install new seat retainer (13) with seat (12)
into body (1) cav i ty with the seat facing down­ ward toward the angled seat ing surface of
the pop pet (8). Tighten seat re tain er to the
following torque val ue: 12 – 15 Ft-lbs (16 – 20
Nm).

11. Reinstall diaphragm subassembly and spring
chamber subassembly per Section VI, Steps
B.9. – B.10.

12. Bench test unit for suitable operation. NOTE:

Regulators are not tight shutoff devices.
Even if pressure builds up beyond set point,
a reg u la tor may or may not develop bubble
tight shutoff.

13. Pressurize with air and spray liquid leak de­ tec tor around body (1) and spring cham ber
(6) to test for leakage. En sure that an outlet
pressure is main tained during this leak test
of at least mid-range spring level; i.e. 2-100
psig (.14-6.9 Barg) range spring, 51 psig
(3.5 Barg) test pres sure minimum.

4

IOM-P4

SECTION VII

VII. TROUBLE SHOOTING GUIDE

1. Erratic operation; chattering.

Possible Causes

A. Oversized regulator; inadequate rangeability. A1. Check actual fl ow conditions, re-size regulator for minimum and maximum
fl ow.
A2. Increase fl ow rate.
A3. Decrease regulator pressure drop; decrease inlet pressure by placing a
throttling orifi ce in inlet piping union.
A4. Install next step higher range spring.
A5. Before replacing regulator, contact factory.
B. Worn poppet; inadequate guiding. B. Replace trim ( possible body replacement).
C. Weakened/broken poppet spring. C. Replace poppet spring. De ter mine if corrosion is causing the failure.

2. Regulator can't pass suffi cient fl ow.

A. Regulator undersized. A1. Confi rm by opening bypass valve together with regulator.
A2. Check actual fl ow conditions, re-size regulator; if regulator has inadequate
capacity, replace with larger unit.
B. Incorrect range spring (adjusting aluminum knob B. Replace range spring with proper higher range.
CW does not raise pressure to proper level).
C. Too much droop. C1. Review droop expected.
C2. Contact factory.

Remedies

RemediesPossible Causes

3. Sluggish operation.

RemediesPossible Causes

A. Fluid too viscous. A. Heat fl uid. Contact factory.

4. Excessive pressure downstream.

Possible Causes Remedies

A. Regulator not closing tightly. A. Inspect the seating. Clean and lap metal seat surfaces; replace if lapping
does not remedy. If composition seats are depressed, nicked or embedded
with debris, replace trim.
B. Downstream block. B. Check system; isolate (block) fl ow at regulator inlet - not outlet. Relocate
regulator if necessary.
C. No pressure relief protection. C. Install safety relief valve, or rupture disc.
D. Restricted diaphragm movement. D. Ensure no moisture in spring chamber at temperatures below freeze point.

IOM-P4

5

SECTION VIII

VIII. 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 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.

NOTES

6

IOM-P4

Figure 2:

Repair Parts
Item No. Description

1 Body
2 Adjusting Screw
3 Knob Nut
4 Knob
5 Spring Button
6 Spring Chamber
7 Diaphragm Subassembly

7.1 Diaphragm -----------------------‡‡

7.2 Actuator Post

7.3 Actuator Nut

7.4 Actuator Gasket -----------------‡‡

7.5 Actuator O-ring ------------------‡‡
8 Poppet --------------------------------- ‡‡
9 Poppet Spring -----------------------‡‡
10 Diaphragm Gasket ----------------- ‡‡
11 O-ring ----------------------------------‡‡
12 Seat ------------------------------------ ‡‡
13 Seat Retainer ------------------------ ‡‡
15 Range Spring
16 Spring Clip
17 Back-up Ring-------------------------‡‡
21 Inline Filter ---------------------------- ‡‡
39 Snap in cover

Kit B

IOM-P4

‡‡ Recommended Spare Part

7

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.

Cashco, Inc.
P.O. Box 6
Ellsworth, KS 67439-0006
PH [phone]
Fax. # [phone]
www.cashco.com
email: [e-mail]

Printed in U.S.A. P4-IOM

Cashco GmbH
Handwerkerstrasse 15
15366 Hoppegarten, Germany
PH [phone]
Fax. No. [phone]
www.cashco.com
Email: [e-mail]

Cashco do Brasil, Ltda.
Al.Venus, 340
Indaiatuba - Sao Paulo, Brazil
PH [phone]
Fax. No.
www.cashco.com
Email: [e-mail]