INSTALLATION, OPERATION & MAINTENANCE MANUAL (IOM)
IOM-P5
MODEL P5
PISTON SENSING SINGLE STAGE
PRESSURE REDUCING REGULATOR
SECTION I
I. DESCRIPTION AND SCOPE
The Model P5 is a pressure reducing regulator used to control downstream (outlet or P2 ) pressure. The unit is suitable
for gaseous or liquid services. Available in sizes 1/4" (DN8), 3/8" (DN10) and 1/2" (DN15). Refer to Technical Bulletin
P5-TB for design conditions and selection recommendations.
SECTION II
II. INSTALLATION
11/13
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.
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.
11. Regulators are not to be buried un der ground.
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.
12. For insulated piping systems, recommendation is
to not insulate regulator.
III. PRINCIPLE OF OPERATION
1. Movement occurs as pressure variations register on the piston (14). The registering pressure
is the outlet, P2, or downstream pressure. The
range spring (15) opposes piston move ment. As
outlet pressure drops, the range spring push es
SECTION III
the piston down, opening the port; as outlet pres sure in creas es, the piston push es up and the port
opening clos es.
2. A failure of the piston seals (19.20) will cause the
reg u la tor to fail open.
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
piston (see Sec tion IV. Startup, Step 7). Higher pressures could dam age the di a phragm. (Field hydro static
tests fre quent ly de stroy di a phragms. DO NOT HYDROSTATIC 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.
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) clockwise (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 ed. Close the
outlet (down stream) block valve.
SECTION V
2. If the regulator and system are to both be shut
Do not walk away and leave a bypassed
regulator unattended.
down, slowly close the inlet (upstream) block
valve. Close the outlet (downstream) valve only
if reg u la tor re mov al is required.
CAUTION
IOM-P52
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:
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.
SECTION VI
Figure 1:
Piston Subassembly
3. Refer to Figure 2 for Model P5 basic reg u -
la tor and Figure 1 for the piston subassembly.
B. Piston 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 the
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 (4) 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).
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. Remove pusher plate (18).
4. Remove snap ring (7) from piston.
5. Lift piston (14) out of body (1) and remove back-
up ring (19) and piston o-ring (20). Remove
body gas ket (10).
6. Clean body (1) according to owner's procedures. 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. Contact
factory for details.
7. Inspect and replace any necessary parts.
Use only parts man u fac tured and supplied by
Cashco, Inc. for these products. See Section
VIII.
8. Place the gas ket (10) onto the body (1) fl ange.
Use o-ring lube on o-ring (20) and slide o-ring
and back-up ring (19) on piston (14). Place
piston sub as sem bly into the body (1).
9. Install snap ring (7) above piston assembly.
Position pusher plate (18) on top of piston post.
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 body 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 of at least midrange spring level; i.e. 2-100 psig (.14-6.9 Barg)
range spring, 51 psig (3.5 Barg) test pres sure
min i mum.
IOM-P5
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