cashco 8311LP Instruction manual

Vent or
Reservoir
Bypass
Supply
@ P1
SRV
PI
Model 8311HP or 8311LP
Back Pressure/Relief
Regulator
System
Recommended Piping Schematic
for Models 8311HP/LP
INSTALLATION, OPERATION & MAINTENANCE MANUAL IOM-8311HP/LP-BASIC
12-13
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 are recommended for NPT screwed instal-
lations to allow removal from piping.
4. An inlet pressure gauge should be located approximately
ten pipe diameters upstream, and within sight.
5. All installations should include a upstream relief device
if the inlet pressure could exceed the pressure rating of
any upstream equipment or the maximum inlet pressure
rating of the unit.
6. Clean the piping of all foreign material including chips,
welding scale, oil, grease and dirt before installing the
regulator. Strainers are recommended.
l. DESCRIPTION AND SCOPE
The Model 8311 is a high capacity back pressure / relief regulator with double seat design used to control upstream (inlet or P1)
pressure. Sizes are 1-1/2" (DN40), 2" (DN50), 2-1/2" (DN65), 3" (DN80) and 4" (DN100). With proper trim utilization, the unit
is suitable for liquid, gaseous, or steam service. Refer to Technical Bulletin 8311-TB for design conditions and selection recom-
mendations.
This is not a safety device and must not be substituted for a code
approved pressure safety relief valve or rupture disc.
SECTION II
II. INSTALLATION
7. In placing thread sealant on pipe ends prior to en-
gagement, ensure that excess material is removed and
not allowed to enter the regulator upon start-up.
8. Flow Direction: Install so the flow direction matches the
arrow on the body. Install an external sensing line (1/2"
O.D. tubing minimum) from the 3/8" NPT connection
to a point upstream, preferably at gauge location. If
regulator pipe line is expanding to a larger pipe line,
always connect sensing line to the larger pipe line.
9. For best performance, install in well drained horizontal
pipe, properly trapped, if a steam service application.
MODELS 8311HP AND 8311LP
BACK PRESSURE / RELIEF REGULATORS
SECTION l
CAUTION
Installation of adequate overpressure protection is recom-
mended to protect the regulator from overpressure and
all downstream equipment from damage in the event of
regulator failure.
WARNING
The maximum inlet pressure is equal to 1.3 times the
larger number of the stated range spring on the nameplate,
and is the recommended “upper operative limit” for the
sensing diaphragm. Higher pressures could damage the
diaphragm. (Field hydrostatic tests frequently destroy
diaphragms. DO NOT HYDROSTATIC TEST THRU AN
INSTALLED UNIT; ISOLATE FROM TEST.)
CAUTION

2 IOM-8311HP/LP
SECTION III
2. If the regulator and system are to both be shutdown,
slowly close the inlet (upstream) block valve. Close the
outlet (downstream) valve only if regulator removal is
required.
Do not walk away and leave a bypassed regulator
unattended!
V. SHUTDOWN
1. On systems with a bypass valve, and where system
pressure is to be maintained as the regulator is shut
down, slowly open the bypass valve while closing the inlet
(upstream) block valve. Fully close the inlet (upstream)
block valve. (When on bypass, the system pressure
must be constantly observed and manually regulated.)
Close the outlet (downstream) block valve.
SECTION V
IV. START-UP
1. Start with the block valves closed. A bypass valve may
be used to maintain inlet pressure in the upstream
system without changing the following steps.
2. Relax the range spring by turning the adjusting screw
counter clockwise (CCW) (viewed from above) a min-
imum of three (3) full revolutions. This reduces the inlet
(upstream) pressure setpoint.
3. If it is a “hot” piping system, and equipped with a bypass
valve, slowly open the bypass valve to preheat the sys-
tem piping and to allow slow expansion of the piping.
Ensure proper steam trap operation, if installed. Closely
monitor inlet (upstream) 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 inlet (upstream) block valve.
5. Slowly open the outlet (downstream) block valve ob-
serving the inlet (upstream) pressure gauge. Determine if
the regulator is flowing. If not, slowly rotate the regulator
adjusting screw counter clockwise (CCW) (viewed from
above) until flow begins.
6. Continue to slowly open the outlet (downstream) block
valve until fully open.
7. Observing the inlet (upstream) pressure gauge, rotate
the adjusting screw clockwise (CW) slowly until the inlet
pressure 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 the adjusting screw CCW until
the pressure decreases.
9. When flow 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 flow to a level near its expected normal
rate, and reset the regulator setpoint by turning the
adjusting screw CW (viewed from above) to increase
inlet pressure, or CCW to reduce inlet pressure.
11. Reduce system flow to a minimum level and observe
setpoint. Inlet pressure will rise from the setpoint of Step
10. The maximum rise in outlet pressure on decreas-
ing flow should not exceed the stated upper limit of the
range spring by greater than 10%; i.e. 10-40 psig (.69-
2.76 Barg) range spring, at low flow the outlet pressure
should not exceed 44 psig (3 Barg). If it does, consult
factory.
SECTION IV
III. 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 opposes
diaphragm movement. As inlet pressure drops, the range
spring pushes the diaphragm down, closing the ports;
as inlet pressure increases, the diaphragm pushes up
and the ports open.
2. A complete diaphragm failure will cause the regulator
to fail closed.
11. Regulators are not to be direct buried underground.
12. For insulated piping systems, recommendation is to not
insulate regulator.
10. Basic Regulator - (Refer to Figure 1): Regulator may
be rotated around the pipe axis 360°. Recommended
position is with spring chamber vertical upwards. Orient
such that the spring chamber vent hole does not collect
rainwater or debris.
CAUTION

3IOM-8311HP/LP
SECTION VI
VI. MAINTENANCE
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 per-
sonal injury.
A. General:
1. Maintenance procedures hereinafter are based
upon removal of the regulator unit from the pipeline
where installed.
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 1 for standard regulator (NOTE:
“LP” variation has larger diaphragm area than
“HP” variation). Refer to Figures 2 and 3 for option
blow-ups.
B. Diaphragm Replacement:
1. Using an overhead hoist, lift regulator onto a flat
surface work bench.
SPRING UNDER COMPRESSION. Prior to removing flange
bolts, relieve spring compression by backing out the ad-
justing screw. Failure to do so may result in flying parts
that could cause personal injury.
2. Relax range spring (28) by turning adjusting
screw (or T-bar) (32) CCW (viewed from above)
until removed from spring chamber (13). Count
and record the number of revolutions in the box
below:
Number of revolutions required to relax range
spring:_________
3. Draw or embed a match mark between diaphragm
case (14) and spring chamber casting (13) along
flanged area.
4. Remove all flange nuts (30) and bolts (29).
5. Remove spring chamber (13), spring button (27),
and range spring (28).
6. Draw second match mark on diaphragm case
(14) flange in alignment with a match mark on the
threaded end of the plug and stem assembly (12)
to indicate “free vertical movement” position of the
plug and stem assembly (12).
7. Securing the “flats” on the threaded end of the plug
and stem assembly (12) with adjustable wrench,
remove pressure plate nut (24) by rotating CCW
(viewed from above).
NOTE: Do not rotate the plug and stem assembly
(12). The plug (12.1) and seat rings (10 & 11) have
been mechanically lapped at the factory per ANSI
Class II seat leakage and assembled to provide
optimum “free vertical movement”.
8. Pry loose pressure plate (22) from diaphragm(s) (20)
and remove both. Inspect to ensure no deformation
due to over-pressurization. If deformed, replace.
NOTE: 1. Not removing the pusher plate (17) or
rotating the plug and stem assembly (12) will provide
performance equal to original factory performance
when diaphragm(s) (20) is replaced with a like
diaphragm(s) (20). Refer to Section VI.C, steps
12 and 13 for correct diaphragm setting if pusher
plate (17) or stem lock nut (19) is removed, or plug
and stem assembly (12) is rotated.
2. Refer to quantity of diaphragm(s) (20) incorpo-
rated in the bill of materials listing. Depending on
outlet pressure level, multiple metal diaphragms
may be “stacked”.
9. Remove diaphragm gasket (21) and pusher plate
gasket (18). Clean gasket sealing surfaces thor-
oughly.
10. Install new diaphragm gasket (21) on diaphragm
case (14) flange and new pusher plate gasket (18)
on pusher plate, if required. NOTE: No gaskets
utilized with a composition (soft) diaphragm.
11. Position new diaphragm(s) (20) over threaded end
of plug and stem assembly (12).
12. Ensuring that the curved outer rim side of the pres-
sure plate (22) rests against the diaphragm(s) (20)
directly, place the pressure plate (22) over threaded
end of the plug and stem assembly (12).
13. Reposition pressure plate nut (24) on threaded
end of plug and stem assembly (12) and tighten
to 75-80 ft/lbs. (108-115 N-M) for metal or 30-35
ft/lbs. (40-47 N-M) for composition diaphragm.
Maintain alignment of match marks on the plug
and stem assembly (12) with second match mark
on the diaphragm case (14) flange. NOTE: Use
two flange bolts (29) to keep multiple diaphragms
(20) bolt holes properly aligned while tightening the
pressure plate nut (24). DO NOT USE FINGERS
TO HOLD DIAPHRAGMS (20) DURING TIGHTEN-
ING OF NUT (24).
14. Set range spring (28) on retainer hub of pressure
plate (22).
15. Place multi-purpose, high temperature grease into
depression of spring button (27) where adjusting
screw (or T-bar) (32) bears. Set spring button (27)
onto range spring (28); ensure spring button (27)
is laying flat.
16. Aligning the match marks, place spring chamber
(13) over the above stacked parts. Install all bolts
WARNING
WARNING

4 IOM-8311HP/LP
Model Diaphragm
Material Torque Bolt Size
8311HP ALL 45 ft-lbs (61 N-M) 5/8" Ø
8311LP ALL 45 ft-lbs (61 N-M) 1/2" Ø
8. Examine the lower guide bushing (4) for wear;
determine if debris has gathered in lower guide
bushing (4) zone. Clean, if necessary. If unable
to clean then remove per Step 16. below.
9. Remove upper body gasket (6) and clean sealing
surface thoroughly.
10. Install plug and stem assembly (12) into body (1)
and place new body gasket (6) onto body (1).
11. Align match mark and replace bonnet (2) on
body (1) and reinstall bonnet flange stud nuts (8).
Mechanically tighten nuts (8) in alternating cross-
ing pattern that allows bonnet (2) to be pulled up
evenly. Recommended torques are as follows:
12. Fully thread stem lock nut (19) and pusher plate (17)
on end of plug and stem assembly (12). Refer to
Figure 1 for correct orientation of the pusher plate
(17).
13. Calibrate diaphragm (20) setting and correct plug
and stem assembly (12) travel as follows:
a) Hand press plug and stem assembly (12) tight
into the seats (10 and 11).
b) Adjust the pusher plate (17) so that the gasket
surface face of the pusher plate (17) is flush with
the top of the diaphragm case (14) flange.
c) Draw the stem lock nut (19) up tight against
the pusher plate (17) by holding “flats” milled
on pusher plate (17).
14. Grasp threaded end of plug and stem assembly
(12) by hand and ensure that the assembly moves
freely by lifting the plug and stem assembly (12)
in and out of the seats (10 and 11), making sure it
does not “stick”. If it does not move freely, rotate
plug and stem assembly (12) CW until new posi-
tion is found which allows optimum “free vertical
movement” in and out of seats.
15. Proceed with diaphragm (20) assembly instructions
in accordance with Section IV.B., steps 10 through
18. NOTE: Do not rotate plug and stem assembly
(12) from optimum “free vertical movement” position
during final assembly.
16. If necessary, remove bottom flange (3) bolting
(7)(8). Clean cavity. Examine lower guide bushing
for wear. Replace bottom bonnet if lower guide
bushing is worn or damaged.
17. Replace bottom flange (3) on body (1) and re-
install bolting(7)(8). Mechanically tighten nuts (8)
in alternating crossing pattern that allows bottom
flange (3) to be brought up evenly. Refer to Step
11. for recommended torques.
Regulator Size Torque Bolt Size
1-1/2" - 2" 50 ft/lbs (68 N-M) 1/2" Ø
3" - 4" 50 ft/lbs (68 N-M) 5/8"Ø
NOTE: Never replace bolting (29) (30) with just
any bolting, if lost. Bolt heads and nuts are marked
with specification identification markings. Use only
proper grades as replacements.
17. Reinstall adjusting screw (or T-bar) (32) with lock
nut (or lever) (33). Rotate number of revolutions
recorded in Step 2. above.
18. Pressurize inlet portion of valve. Soap solution test
around bolting (29)(30), diaphragm case (14), and
spring chamber (13) flanges for leakage. Ensure
that an inlet pressure is maintained during this leak
test of at least mid-range spring level; i.e. 10-40
psig (.69-2.76 Barg) range spring, 25 psig (1.72
Barg) test pressure minimum.
C. Trim Inspection:
1. To inspect the internal trim parts, refer to Section
VI.A. and B.1 through 9 for diaphragm replacement
and proceed as follows.
2. Secure the “flats” on the threaded end of the plug
and stem assembly (12) with adjustable wrench
and remove pusher plate (17), stem lock nut (19)
by rotating CCW (viewed from above). NOTE: Do
not rotate the plug and stem assembly (12).
3. Draw or embed a match mark between body (1)
and bonnet (2).
4. Loosen and remove bonnet flange stud nuts (8)
CCW (viewed from top) and remove bonnet (2).
Inspect the upper guide bushing (4) for excessive
wear. Replace, if worn. NOTE: DO NOT REMOVE
BOTTOM FLANGE (3). The bottom flange (3) acts
as a guide to align the plug and stem assembly
(12) into the seat rings (10 and 11).
5. Firmly grasp end of plug and stem assembly (12)
by hand and pull out of the body (1) cavity.
6. Inspect the seating surfaces of the plug (12.1) for
nicks or excessive wear.
7. Using a flashlight or other light source, examine
the interior of body (1) cavity. Also, inspect the
seating surfaces of both the upper and lower seat
rings (10 and 11) for excessive wear. If either the
plug (12.1) or the seat rings (10 and 11) are worn
and in need of replacement, contact the factory
for authorization to return unit for repair. NOTE:
Overhaul and replacement of trim parts is not easily
accomplished by non-factory trained personnel.
(29) and nuts (30) by hand tightening. Mechani-
cally tighten bolting (29) (30) in a crossing pattern
that allows spring chamber (13) to be pulled down
evenly. Recommended torques are as follows:

5IOM-8311HP/LP
A. Plugged spring chamber vent. A. Clean vent opening.
B Fluid too viscous. B. Heat fluid. Contact factory.
A. Normal-life diaphragm failure. A. Replace diaphragm.
B. Abnormal short-life diaphragm failure. B1. Can be caused by excessive chattering. See No. 1. to remedy chatter.
B2. Can be caused by corrosive action. Consider alternate diaphragm material.
B3. For composition diaphragms, ensure not subjecting to over-temperature
conditions.
B4. Upstream (inlet) pressure buildup occuring that overstresses dia-
phragms. Relocate regulator or protect with safety relief valve.
A. Regulator undersized. A1. Confirm by opening bypass valve together with regulator.
A2. Check actual flow conditions, resize regulator; if regulator has inadequate
capacity, replace with larger unit.
B. Incorrect range spring (screwing out CCW of B. Replace range spring with proper lower range. Contact factory.
adjusting screw does not allow bringing pressure
to a stable and proper level).
C. Too much build. C1. Review build expected.
C2. Contact factory.
D. Restricted diaphragm movement. D. Ensure no moisture in spring chamber at temperatures below freeze point.
Ensure no dust or debris entering vent opening. If rainwater or debris can
enter, re-orient spring chamber.
RemediesPossible Causes
RemediesPossible Causes
RemediesPossible Causes
A. Oversized regulator; inadequate rangeability. A1. Check actual flow conditions, resize regulator for minimum and maximum
flow.
A2. Decrease regulator pressure drop; decrease inlet pressure by placing a
throttling orifice in inlet piping union.
A3. Install next step higher range spring. Contact factory.
A4. Before replacing regulator, contact factory.
B. Worn plug/stem assembly; inadequate guiding. B1. Contact factory.
Remedies
Possible Causes
2. Leakage through the spring chamber vent hole.
3. Upstream pressure too high.
4. Sluggish operation.
SECTION VII
VII. TROUBLE SHOOTING GUIDE
1. Erratic operation; chattering.

6 IOM-8311HP/LP
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–
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 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".
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.
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 ap-
propriate ratings and new product code to accommodate
the recommended part(s) changes.
SECTION VIII
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.

7IOM-8311HP/LP
Item No. Description
1 Body
2 Bonnet
3 Bottom Flange
4 Guide Bushing
5 Stem Bushing
6 Body Gasket
7 Body Stud
8 Body Stud Nut
10 Upper Seat Ring
11 Lower Seat Ring
12 Valve Plug Assembly
12.1 Plug
12.2 Stem
12.3 Pin (Groove)
13 Spring Chamber
14 Diaphragm Case
15 O-ring
16 Bonnet Nut
17 Pusher Plate
18 Pusher Plate Gasket
19 Stem Lock Nut
20 Diaphragm
21 Diaphragm Gasket
22 Pressure Plate
24 Pressure Plate Nut
25 Diaphragm Ring
27 Spring Button
28 Range Spring
29 Flange Bolt
30 Flange Nut
31 Nameplate
32 Adjusting Screw (or Handwheel Assembly)
33 Adjusting Screw Lock nut (or Lever)
34 Seal Washer
35 Closing Cap
36 Closing Cap Gasket
43 Pipe Plug
NOT SHOWN
54 Drive Screw
55 Flow Arrow
Figure 2: Model 8311HP only – Option-80, High Pressure
Spring Chamber Construction
Figure 3: Model 8311HP/LP, Option-1 Closing Cap
Figure 1: Standard Model 8311HP/LP
(NOTE: Variation “LP” has a larger diaphragm area than the “HP”.)

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. IOM-8311HP/LP
Cashco GmbH
Handwerkerstrasse 15
15366 Hoppegarten, Germany
PH [phone]
Fax. No. [phone]
www.cashco.com
Email: [email protected]
Cashco do Brasil, Ltda.
Al.Venus, 340
Indaiatuba - Sao Paulo, Brazil
PH [phone]
Fax. No.
www.cashco.com
Email: [email protected]