Cashco B2 User Manual

INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM)

IOM-B2

11/13

MODEL B2

BACK PRESSURE REGULATOR

SECTION l

I. DESCRIPTION AND SCOPE

The Model B2 is a back pressure regulator used to control upstream (inlet or P1) pressure. Sizes are 1/4" and
3/8" NPT (DN8 and DN10) FNPT or 1/2" (DN15) with Tri-Clamp connections. The unit is suitable for gaseous or
liquid service. Refer to Technical Bulletin B2-TB for design conditions and selection rec om men da tions.

CAUTION

This is not a safety device and must not be substituted for a code approved pressure safety relief valve or a
rupture disc.

SECTION II

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.

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.

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, Model B2):
Regulator may be rotated around the pipe axis
360°. Recommended position is with knob (4)
ver ti cal upwards.

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. The registering pressure is the inlet,

, or upstream pressure. The range spring opposes

P

1

diaphragm movement. As inlet pressure drops, the
range spring pushes the dia phragm down, closing

SECTION IV

IV. STARTUP

the port; as inlet pres sure in creas es, the diaphragm
pushes up and the port opens.

2. A complete diaphragm failure will cause the reg u la tor
to fail closed.

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 bypass valve may
be used to maintain inlet pressure in the upstream
system without changing the fol low ing steps.

2. Relax the range spring (15) by turning knob (4) counter
clockwise (CCW) a minimum of three (3) full rev o lu­ tions. This reduces the inlet (up stream) pres sure
setpoint.

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. Assure proper steam trap operation if
installed. Closely monitor inlet (up stream) pres sure
via gauge to assure 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 inlet (upstream) block valve.

5. Slowly open the outlet (downstream) block valve
ob serv ing the inlet (upstream) pressure gauge. De­ ter mine if the regulator is fl owing. If not, slowly rotate
the regulator adjusting screw CCW until fl ow begins.

6. Continue to slowly open the outlet (downstream)
block valve until fully open.

7. Observing the inlet (upstream) pressure gauge,
ro tate knob (4) clockwise (CW )slowly until the inlet
pres sure begins to rise. Rotate CW until the desired
setpoint is reached.

8. Continue to slowly open the inlet (upstream block
valve. If the inlet (upstream) pressure exceeds the
desired setpoint pressure, rotate knob (4) CCW until
the pres sure decreases.

9. When fl ow is established steady enough that both
the outlet and inlet block valves are fully open, begin
to slowly close the bypass valve, if installed.

10. Develop system fl ow to a level near its expected
normal rate, and reset the regulator setpoint by turn­ ing knob (4) CW to increase inlet pressure, or CCW
to reduce inlet pressure.

11. Using a downstream valve, reduce system fl ow to a
min i mum level and ob serve setpoint. Inlet pres sure
will rise from the setpoint of Step 9. (Ensure this rise
does not exceed the stated upper limit of the range
spring by greater than 50%, i.e. 2-50 psig (.14 - 3.4
Barg) range spring, at maximum fl ow the inlet pres-
sure should not exceed 1.5 x 50 psig (3.4 Barg), or
75 psig (5.2 Barg). If it does, consult factory).

12. Increase fl ow to maximum lev el, if possible. Inlet
(up stream or P
setpoint as necessary at the normal fl ow rate.

) pressure should fall off. Re ad just

1

SECTION V

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 ed. Close the outlet (down stream) block
valve.

CAUTION

Do not walk away and leave a bypassed regulator
unattended.

IOM-B22

2. If the regulator and system are to both be shut
down, slowly close the inlet (upstream) block

SECTION VI

VI. MAINTENANCE

WARNING

SYSTEM UNDER PRESSURE. Prior to performing
any maintenance, isolate the regulator from the sys­tem and relieve all pressure. Failure to do so could
result in personal injury.

A. General:

1. Maintenance procedures hereinafter are

based upon re mov al of the regulator unit
from the pipeline where in stalled.

valve. Close the outlet (downstream) valve only
if reg u la tor re mov al is required.

Figure 1: Diaphragm Subassembly

spring button (5) should remain inside the
spring cham ber.

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 Model B2 basic reg u -

la tor and Figure 1 for the diaphragm sub as ­sem bly.

B. Diaphragm Replacement - Model B2:

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.

WARNING

SPRING UNDER COMPRESSION. Prior to removing
spring chamber, relieve range spring compression
by turning the knob CCW until rotation comes to a
complete stop. Failure to do 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
(4) before removing the spring chamber (6)
from the body (1).

3. Remove spring chamber (6) by grasping the

fl ats and turning CCW. Upon removal, the
range spring (15), range spring clip (16), and

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).

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: ALL
SIZES: 15 Ft-lbs (20 Nm).

9. Place the diaphragm gas
body (1) diaphragm fl ange. Place di a phragm
sub as sem bly on top of the gasket (10).

ket (10) onto the

IOM-B2

3

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: ALL SIZES: 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
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 subassembly and
diaphragm subassembly per Section VI,
Steps B.1.–B.4.

4. 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.

5. Install new seat retainer (13) with seat (12)
into body (1) cav i ty with the seat (12) facing
down ward. Tighten seat re tain er (13) to the
following torque val ue: ALL SIZES: 2–15 Ft-
lbs (16–20 Nm).

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

7. 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.

2. Remove seat retainer (13) and seat (12) by
turning CCW.

3. 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.

8. 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.

IOM-B24

SECTION VII

VII. TROUBLE SHOOTING GUIDE

1. Erratic operation; chattering.

Possible Causes Remedies

A. Oversized regulator; inadequate rangeability. A1. Check actual fl ow conditions, re-size regulator for minimum and maximum fl ow.

2. Regulator inlet (upstream) too high.

Possible Causes Remedies

A. Regulator undersized. A1. Confi rm by opening bypass valve together with regulator.

B. Incorrect range spring (screwing in CW of
adjusting screw does not allow bringing
pressure level up to proper level).

C. Too much rise (build). C1. Review rise (build) expected.

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.

A2. Check actual fl ow conditions, re-size regulator; if regulator has inadequate
capacity, replace with larger unit.

B. Replace range spring with proper lower range.

C2. Contact factory.

3. Sluggish operation.

Possible Causes Remedies

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

IOM-B2

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

IOM-B26

Figure 2: Model B2

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 with Seat (#8)--‡‡

7.3 Actuator Nut

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

7.5 Actuator O-ring ------------------‡‡
10 Diaphragm Gasket ----------------- ‡‡
12 Seat ------------------------------------ ‡‡
13 Seat Retainer ------------------------‡‡
15 Range Spring
16 Spring Clip
21 Inline Filter ---------------------------- ‡‡
39 Snap in cover

‡‡ Recommended Spare Part

Kit B

IOM-B2

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. B2-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]