INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM)
IOM-POSR-2
12-13
MODEL POSR-2
PILOT OPERATED PRESSURE RE DUC ING REGULATOR
SECTION I
I. DESCRIPTION AND SCOPE
The POSR-2 is a pilot operated pressure reducing reg u la tor used to control downstream (P2) pressure. Sizes are
1", 1-1/2", 2", 3" and 4" (DN25, 40, 50, 80, 100). The unit is suitable for steam service only. Refer to Technical Bulletin POSR-2-TB for design conditions and selection recommendations. NOT RECOMMENDED FOR DEAD END
SERVICE.
SECTION II
II. INSTALLATION
A. General:
WARNING
Do not dead end (no fl ow demand) downstream of POSR-2
if P1 - Inlet Pressure is greater than max i mum allowable
outlet design pressure.
Max. Allowable
Spring Range Outlet Pressure
5-15 psig (0.34–1.03 Barg) 100 psig (6.9 Barg)
10–40 psig (0.69–2.8 Barg) 200 psig (13.8 Barg)
30–80 psig (2.1–5.5 Barg) 200 psig (13.8 Barg)
70–150 psig (4.8–10.3 Barg) 200 psig (13.8 Barg)
B. Piping the Valve:
1. An inlet block valve should always be in stalled.
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 in stal la tions to allow removal from
piping.
4. An outlet pressure gauge should be located ap prox i mate ly ten pipe diameters down stream,
and within sight.
FIGURE 1
Recommended Piping Schematic for POSR-2
CAUTION
Installation of adequate overpressure pro tec tion is recommended to pro tect the reg u la tor from overpressure and
all down stream equip ment from damage in the event of
regulator failure.
CAUTION
For welded installations, all internal trim parts, seals and
diaphragm(s) must be removed from reg u la tor body prior to
welding into pipeline. The heat of fusion welding will dam age non-metallic parts if not re moved. NOTE: This does
not apply to units equipped with extended pipe nip ples.
5. All installations should include a downstream
re lief device if the inlet pressure could exceed the pressure rating of any downstream
equip ment or the maximum allowable outlet
pres sure rating of the unit.
6. Clean the piping of all foreign material in clud ing chips, welding scale, oil, grease and
dirt before installing the regulator. Strainers
are recommended.
CAUTION
DO NOT HYDROSTATIC TEST THROUGH AN IN STALLED
UNIT, INCLUDING PILOT; ISOLATE BOTH PILOT AND MAIN
VALVE FROM TEST. The upper range spring pressure
level listed on the nameplate is the rec om mend ed “upper
operative limit” for the sens ing diaphragm(s) in the pilot.
Higher pres sures could cause internal damage. In addition,
note on the name plate that the Inlet and Outlet pressure
and tem per a ture ratings are at different levels.
7. In placing thread sealant on pipe ends prior
to en gage ment, assure that excess material
is removed and not allowed to enter the reg u la tor upon start-up.
8. Flow Direction. Install so the fl ow direction
match es the fl ow arrow on the body.
9. The POSR-2 comes factory piped between
the pilot supply and pilot loading. Install an
external sensing line from the 1/4" NPT con nec tion opposite the factory piped pilot load ing
port to a point downstream at gauge location;
use 1/4" OD metal tubing for dis tanc es 4 ft
(1.2 m) or less, and 3/8" OD metal tubing (requires 1/4" x 3/8" tubing adapter) for distances
greater than 4 ft. (1.2 m). The sensing line
should always be sloped down ward so that
condensation will drain away from the pilot.
If regulator pipe line is ex pand ing to a larger
pipe line, always connect sens ing line to the
larger pipe line.
10. See Figure 2 for installation ori en ta tion for
hor i zon tal or vertical piping. For best per for mance Cashco rec om mends in stall ing in a well
drained horizontal pipe, prop er ly trapped.
Position “H”: Horizontal Pipe. Re quires user
to in stall sensing line on down stream pip ing.
Position “VD”: Vertical pipe with down wards
fl ow direction. Requires user to install
sensing line on down stream pip ing.
Position “VU”: Vertical pipe with up wards
fl ow di rec tion. Pilot valve and main valve
shipped as separate units. Re quires user
to install pilot valve at down stream pipe tap
with a pipe nipple (not provided), provide
and install tub ing (4 tube fi ttings and two 4
ft (1.2 m) lengths of 1/4" OD copper tubing
supplied) to load ing cham ber tap and to
body tap from pilot valve.
P
1
11. Recommended installation is with pilot valve
spring chamber vertical upwards. Orient such
that the spring chamber vent hole does not
collect rainwater or debris.
12. Regulators are not to be buried underground.
13. For insulated piping systems, rec om men da tion
is to not insulate regulator.
III. PRINCIPLE OF OPERATION
A. General:
1. The POSR-2 pilot obtains its operating me di um
from the main valve body inlet. Down stream
pressure (P2) registers on the un der side of
the main valve’s piston and the pilot valve’s
diaphragm(s).
2. The loading pressure on the top side of the
main valve’s piston is an intermediate pres sure
higher than the downstream (P2) pres sure by
the sum of the pressures required to overcome
the main valve’s plug unbalance force and the
piston spring’s force.
3. The pilot has a bleed orifi ce that continu-
ously bleeds part of the loading medium
down stream. In op er a tion, the pilot valve’s
plug can fl ow more medium than is bleed-
SECTION III
ing down stream. This increases the loading
pres sure on the main valve’s plug and opens
valve. Partially closing the pilot valve’s plug will
reduce its fl ow to less than the amount bleed ing
downstream, and allows the loading pres sure
on the main valve’s piston to decay, allowing
partial closing of the main valve’s plug. This
continues until steady-state is de vel oped.
4. The pilot valve’s diaphragm(s) senses the
down stream (P2) pressure and compares
the force generated to the force developed
by the pilot’s range spring.
5. If, during operation, the downstream (P2)
pres sure falls below the pilot valve’s setpoint,
the main valve’s piston senses the reduced
pres sure on its underside and instantly moves
down, increasing the fl ow through the main
valve. At the same time, the pilot valve senses
the reduced pressure and the pilot valve’s plug
IOM-POSR-22
Pipe or tubing installed by customer / installer.
Pipe or tubing installed by Cashco.
POSITION “H”
Pilot valve and main
valve shipped as two
units. Installer to connect
between pilot valve and
main valve for “loading”
and “supply” tubes.
POSITION “VU”
FIGURE 2
Orientation/Arrangement
IOM-POSR-2 3
POSITION “VD”
increases its opening, elevating the loading
pressure on the upper side of the main valve’s
piston. The combined actions increase fl ow
enough to restore the down stream (P
sure to the setpoint.
6. If the downstream (P
) pressure rises above
2
the setpoint, the force developed by the
in creased pressure on the underside of the
piston instantly moves it upward and partially
closes the main valve’s plug. Simultaneously,
the pilot valve’s plug partially closes and al lows the loading pressure to decay through
) pres-
2
SECTION IV
the bleed orifi ce. The reduced loading pres-
sure on the upper side of the piston closes
the main valve’s plug enough to restore the
down stream (P
) pressure to the setpoint.
2
7. Pressure setpoint is adjusted by changing the
com pres sion of the pilot’s range spring by turning the adjusting screw either clockwise (CW)
or counter-clock wise (CCW). Turning the
adjusting screw clockwise (CW) will in crease
the downstream (P
) pressure. Turn ing the
2
adjusting screw counter-clockwise (CCW) will
decrease the down stream (P2) pressure.
IV. START-UP
A. General
1. Start with the block valves closed.
2. Ensure that the needle valve(s) on the
sensing line is opened and downstream (P2)
pressure is in di cat ing on pressure gauge.
3. Relax the pilot valve range spring by turning the adjusting screw counter clockwise
(CCW) (viewed from above) a minimum of
three (3) full revolutions. This reduces the
outlet (downstream) pressure setpoint.
4. Slowly open the bypass valve to preheat the
system piping and to allow slow expansion of
the piping. Assure proper steam trap op er a tion.
Closely monitor outlet (down stream) pressure
via gauge to assure not over-pres sur iz ing.
NOTE: If no bypass valve is in stalled, extra
caution should be used in start ing up a cold
system; i.e. do everything slowly.
If not, slightly close bypass valve, and then
slowly rotate the pilot valve adjusting screw
clockwise (CW) (viewed from above) until fl ow
begins.
7. Continue to alternate slowly closing the by pass valve and then slowly opening the inlet
(upstream) block valve, especially when the
downstream piping sys tem isn’t pres sur ized.
If the outlet (downstream) pressure exceeds
the desired pressure, close the by pass valve
until fully closed. If outlet pressure still re mains above desired level, rotate pilot’s ad just ing screw CCW (viewed from above) in
1/2 revolution increments until outlet pressure reaches desired level. If outlet pressure
is below desired level, rotate pilot’s adjusting
screw CW (viewed from above) until desired
level is reached.
8. When fl ow is established steady enough that
the inlet (upstream) block valve is fully open,
begin to slowly close the bypass valve and
continue until fully closed.
CAUTION
Do not walk away and leave a bypassed regulator unattended when on manual bypass!
5. Slowly open the outlet (downstream) block
valve until fully open. Slightly close the by pass
valve at same time.
6. Slowly open the inlet (upstream) block valve
ob serv ing the outlet (downstream) pressure
gauge. De ter mine if the regulator is fl owing.
9. Develop system fl ow to a level near its ex-
pect ed normal rate, and reset the regulator
setpoint by turning the pilot valve adjusting
screw CW (viewed from above) to increase
outlet pressure, or CCW to reduce outlet pres sure.
10. Reduce system fl ow to a minimum level and
observe setpoint. Outlet pressure will rise from
the set point of Step 9. There should be no
more than a 10% variation in outlet pres sure
over the maximum to minimum fl ow range.
IOM-POSR-24
V. SHUTDOWN
A. General
1. On systems with a bypass valve, and where
system pressure is to be maintained as the
POSR-2 is shut down, slowly open the bypass
valve while closing the inlet (up stream) block
valve. Fully close the inlet (upstream) block
valve. (When on bypass, the system pres sure
must be constantly observed and man u al ly
regulated.) Close the outlet (down stream)
block valve. Close the nee dle valve on the
pilot valve’s sensing line.
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 regulator removal is required.
Close the needle valve on the pilot valve’s
sensing line.
SECTION Vl
VI. MAINTENANCE
CAUTION
SYSTEM UNDER PRESSURE. Prior to performing any
maintenance, isolate the regulator from the sys tem and
relieve all pressure. Failure to do so could result in personal injury.
A. General:
1. Maintenance procedures hereinafter are
based upon removal of the regulator unit from
the pipeline where installed, and main te nance
performed in a workshop.
2. Owner should refer to owner’s procedures for
re mov al, handling, cleaning and disposal of
non-reuseable parts, i.e. gaskets, etc. Cash co
recommends not reusing any gaskets, but
replacing with only new and factory supplied
gaskets.
3. This regulator is supplied from the factory
using a gasket sealing aid, Federal Process
Company, PLS 2, or equal. Such compatible
sealing aids may be utilized by the Owner, if
desired.
4. All indicated item numbers that are with re spect
to the Pilot Valve will be in parenthesis and
underscored, i.e. (14), (PV). All item numbers
that are with respect to the Main Valve will
NOT be underscored, i.e. (1), (MV).
5. Refer to Figures 6 through 12 for item num ber
callouts.
6. Most pilot-operated valve operation problems
center around the pilot valve (PV). Cashco
always rec om mends full maintenance on any
POSR-2 pilot valve (PV) once a POSR-2 is
removed from the pipeline.
B. Separation:
1. Observe orientation of pilot valve (PV) with
re spect to main valve (MV) position “VD”,
“H”, or “VU”, Figures 6, 7 or 8, be fore dis as sem bling.
2. Place main valve body (1) into a vise, oriented
to allow rotation of pilot valve (PV) together
with in ter con nect ing pipe nipple (19).
3. Remove loading tubing (21) at both end fi t tings
(20) by rotating nut CCW (viewed from tubeend). Disengage union (28) where ap pli ca ble
and remove pilot valve (PV).
4. Place pipe wrench on pipe nipple (19) and
rotate CCW (viewed from pilot valve (PV)
end) to removal. Remove main valve (MV)
from vise and set aside.
5. Place pilot valve body (1) in vise. Remove
pipe nipple (19) or other pipe fi ttings (20, 27,
30) as is applicable.
6. Inspect the inside of the pipe and fi ttings for
corrosion, scaling, debris, or fi lming. Prob-
lems here will be an indication of im prop er
condensate cor ro sion control which can
affect the overall operation of the
POSR-2. Install an upstream strainer if scale
or debris ap pears at this point.
IOM-POSR-2 5
7. Remove pilot valve (PV) from vise and set
aside.
C. Pilot Valve (PV):
1. Securely install the pilot valve body (1) in
a vise with the spring chamber (2) directed
upwards.
8. Using a 7/8" deep well socket, remove bel lows
(11) by rotating CCW (viewed from above).
Count and record the number of revolutions
required to remove the bellows (11) in the box
below:
Number of revolutions required to remove
bellows (11):________________.
WARNING
SPRING UNDER COMPRESSION. Prior to re mov ing body
fl ange bolts, relieve spring com pres sion by backing out
the adjusting screw. Failure to do so may result in fl ying
parts that could cause personal injury.
2. Loosen locknut (20) by rotating CCW (viewed
from above) ONLY two revolutions. Relax
range spring (15) by turning adjusting screw
(19) CCW (viewed from above) until removed
from spring chamber (2). Set ad just ing screw
(19) with locknut (20) aside.
3. Draw or embed a match mark between body
casting (1) and spring chamber casting (2)
along fl anged area.
4. Remove all diaphragm fl ange nuts (18) and
bolts (17).
5. Remove spring chamber (2) by lifting up wards.
Re move range spring (15) and spring button
(16).
6. Remove pressure plate(14). Inspect to
en sure that the pressure plate (14) has not
been deformed by overpressure by placing a
thin, straight bar or ruler across the side that
touch es the diaphragm (12). If the pressure
plate (14) does not touch the bar at its center
(i.e. a depression in center), the pressure plate
(14) is deformed and must be replaced.
7. NOTE: Pilot valves (PV) supplied with a 5–15
psig (0.34–1.03 Barg) range spring (15) have
only one di a phragm (12) supplied; all other
spring ranges use two diaphragms (12).
Using a putty knife or similar tool, remove
diaphragm(s) (12) and diaphragm gasket
(13). Inspect diaphragm(s) (12) for cracks or
de for ma tion. Radial creases and cracks indicate over pressure. Cracks circumferentially
in di cate high cycles, and may be due to normal
cycling, or pulsing or chattering if premature.
Discard both diaphragm(s) (12) and gasket
(13).
Inspect the bellows (11) for a crack or joint
failure where leakage is occurring. Replace
bellows (11) if leaking.
9. Remove protruding stem extension (10).
10. Using a fl at, sharp-edged tool, clean body (1)
fl ange where diaphragm gasket (13) seals.
11. Using a wire gauge tool, clean the 0.068"
(1.73 mm) diameter bleed orifi ce located in
the body cavity (smaller of two holes) of any
fi lm or other buildup material that might be
restricting fl ow.
NOTE: Any signifi cant blockage of the bleed
or i fi ce will downgrade a POSR-2’s per for-
mance. If a buildup is form ing, attempt to determine the cause and remove the source.
12. Remove body (1) from vise and reorient with
body cap (9) on top; resecure body (1) in
vise.
13. Remove body cap (9) by rotating CCW (viewed
from above) with hex-end wrench. Hammerrapping the wrench may be necessary, as the
body cap (9) has a metal-to-metal shoulder
joint with the body (1). NOTE: Plug (4.2) and
plug spring (7) may come out with body cap
(9) removal.
14. Remove plug spring (7) and plug (4.2) from
body (1) recess.
15. Using needle nose pliers, carefully remove
the screen (6) from the body (1) recess.
16. Inspect body cap (9), screen (6), plug spring
(7), and plug (4.2) for buildup or fi lming. If
parts are “sticking” together, then improper
condensate corrosion treatment is likely. If
scale or other debris is present, then an up stream strainer is recommended.
17. Using a 5/8" deepwell socket, rotate valve seat
(4.1) CCW (viewed from above) to re mov al.
IOM-POSR-26
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