Pressure Reducing Valve Integral Mount Pilot Installation, Operation

Bulletin No. AY-710-A
GP-11
Pressure Reducing Valve Integral Mount Pilot
Installation, Operation & Maintenance Instructions
Typical Single Stage Reduction Installation (For Steam)
Minimum of 20 Outlet Pipe Diameters
to First Turn or Valve
Minimum 10 Inlet
Pipe Diameters
Control Pipe
(Pitch Down)
Gate Valve
Safety
Valve
Armstrong
Strainer
Globe Valve
GP-11
By-pass
Minimum of 10
Pipe Diameters
From Last Valve or Fitting
Armstrong
Trap
Figure 1-1
This bulletin should be used by experienced personnel as a guide to the installation of the Model GP-11 Pressure Reducing Valve. Selection or
installation of equipment should always be accompanied by competent technical assistance. You are encouraged to contact Armstrong
International, Inc. or its local sales representative for additional information.
Installation Instructions
1. An Armstrong Inverted Bucket Steam Trap is
recommended to drain the condensate at the inlet
of the PRV.
2. An Armstrong Y-Strainer (100 mesh) should be
installed before the PRV to reduce the chance of
dirt fouling.
3. Pressure gauges should be installed before and
after the PRV. The downstream gauge should be
installed in or near the control pipe (5/16" O.D.).
4. Control pipe connections go into 1/4" tapping on
the side of the pilot valve. Be certain the pipe is
pitched away from the PRV to drain condensate
away from the pilot. Erratic control could result if
this is not done. Control pipe length should be a
minimum of 10 outlet pipe diameters from the last
tee, elbow or fitting.
5. If two stage reduction is needed, as much distance
as possible between valves is recommended.
6. A by-pass line around the PRV will allow system
operation while the valve is being serviced.
7. Install a quality gate, globe, or ball valves on the
by-pass line. Leaking valves will cause system
problems.
8. Install the PRV with diaphragm down and with flow
in the direction of the arrow on the body.
9. Do not install a quick opening or quick closing valve
on the downstream side of the PRV.
Start-Up and Adjustment Procedures
Improper adjustment of the pressure reducing valve
may cause hunting, scale problems, water hammer,
etc. and can heavily damage the main parts of the
valve. Adjust the valve as follows:
1. Close the gate valves before and after the pressure
reducing valve and blow fluid leisurely through the
by-pass line. Adjusting the opening of the by-pass
globe valve so as not to blow the safety relief valve.
After draining, be sure to close the by-pass globe
valve.
2. Loosen the lock nut and the adjusting screw to
relieve the pressure on the adjusting spring.
3. Slowly open the inlet side gate valve to the full open
position, and open the outlet side gate valve
enough so that a little fluid can flow through.
4. Slowly turn the adjusting screw clockwise until the
desired pressure is obtained while watching the
pressure gauge at the outlet side.
5. Slowly open the outlet side gate valve to the full
open position.
Table 1-1. Spring Chart
6. After adjustment,
Reduced
tighten the lock nut.
Color Code
Pressure
NOTE: Downstream
1.5 to 3 psig
Silver
usage must be present
3
to
30
psig
Yellow
in order to set any
20 to 100 psig
Red
pressure reducing
80
to
200
psig
Black
valve.
1
Disassembly
Assembly
Note: Before disassembly, check to make sure that
the valves before and after the reducing valve are
closed. Also, make sure that the pressure has been
relieved and that the valves are holding.
A. Disassembly of the Pilot Valve
1. Loosen the #29 lock nut, turn the #28 adjusting
screw counterclockwise and turn until pressure is
relieved from spring.
2. Remove the eight (8) hex head bolts and take out
#25 the adjusting spring, #26 bottom plate, #27
spring retainer and two (2) pilot diaphragms.
3. Remove #19 pilot valve seat [hexagonal part at the
center of the #2 pilot body] and take out the pilot
valve assembly. Care should be taken so that pilot
rod does not fall out of the assembly.
B. Disassembly of the Main Valve
1. Disconnect the copper tubing on the side of the
valve (#31A, #31B, #31C).
2. Remove the four (4) hex head bolts from the #2 pilot
body to remove the pilot from the #1 main body.
Care should be taken when doing this - the main
valve is held by a spring which is compressed.
Once bodies are apart, remove #16 spring retainer,
#17 screen, #15 spring and #6 main valve.
3. Use socket to take out #7 main valve seat.
C. Disassembly of the Main Diaphragm
1. Check to make sure there are no scratches on the
main valve, valve seat or pilot valve. If there are no
scratches, apply lapping compound and re-lap the
valve and seat. (See Bulletin AY-768).
2. Make sure the sliding parts - (Pilot valve stem and
main valve stem) move freely.
3. Pay attention to the length of the pilot valve rod
before assembling the pilot diaphragm. (See Figure
2-1).
a. Space should be given between a straight
edge which is placed on the gasket of the
diaphragm and the pilot valve rod.
4. Before assembling the main diaphragm, make sure
that the main valve is supported correctly by the
spring and spring receiver.
5. Confirm that the retainer and valve rod are
connected correctly.
6. When reassembling the main diaphragm, or
measuring step difference, the main valve must
touch the valve seat. (See Figure 2-2).
7. Make sure that the main diaphragm gasket has
been changed. Proper performance cannot be
obtained in case of the wrong thickness.
8. Replace components in reverse order from
disassembly.
9. Tighten hex nuts and bolts uniformly.
Repair Kits are available for pilot valve, main valve,
tubing, gaskets and diaphragms.
1. Remove all nuts and bolts holding the bottom
diaphragm together.
2. Separate both halves. Remove both #13 main
diaphragms, #11 retainer and #9 valve stem.
STEP DIFFERENCE
Figure 2-1
Figure 2-2
Table 2-1
Pipe Size (in)
Z\x
C|v
1"
1Z|v"
1Z\x
2
2Z|x
3
4
Step Difference
Liquid Gasket
1.5mm
1.5mm
1.5mm
2.0mm
2.0mm
3.0mm
4.0mm
4.0mm
5.0mm
Step Difference
Copper Gasket
2.0mm
2.0mm
2.0mm
2.5mm
2.5mm
3.5mm
4.5mm
4.5mm
5.5mm
2
Before working on the valve, make sure that the inlet strainer is clean, bypass valve is closed and
upstream and downstream pressure gauges are working.
TROUBLESHOOTING GUIDE
Problem
Outlet
pressure does
not reach
desired value.
a. Inlet pressure is not adequate for
desired results.
b. Adjustment is not proper.
c. Orifice is not attached to coupler
(#31B).
d. Orifice of coupler (#31C) is plugged.
e. Pilot valve sensing line is plugged.
f. Pilot valve is clogged.
g. Main diaphragm is damaged.
h. Valve size is too small and cannot
supply enough capacity.
a. Adjustment is not proper.
b. Orifice of coupler (#31B or C) is
plugged.
c. Dirt is either caught between the main
valve and seat or pilot valve and seat.
Secondary
pressure
exceeds the
pressure
setting
d. Dirt is between #9 valve stem and #10
guide.
e. By-pass valve is not shut or is leaking.
f. Sensing line is plugged.
g. Sensing line is not connected.
Operation is
unstable
Excessive
noise is
present
Test
Cause
h. High pressure steam traps are
discharging into outlet side of PRV and
traps are blowing through.
a. Orifice of coupler is partially plugged.
b. Sensing pipe is installed at a point
where there is too much turbulence.
c. Liquid is collecting in sensing line.
d. Quick opening valve located too close
to the outlet or inlet of PRV.
a. Valve size is larger than what was
required.
b. Reduction ratio exceeds 20:1.
c. Steam trap draining inlet of PRV is
plugged.
d. Automatic valve (i.e., solenoid) is too
close to PRV.
Solution
Maximum outlet pressure is 85% of
the inlet with a minimum DP =7 psi
Turn adjusting screw #28 clockwise.
Remove and check.
Raise inlet pressure if possible.
Remove and check.
Remove and check.
Close inlet valve. Remove fittings
#31A and 31B. Turn #28 adjusting
screw counter clockwise until it is
loose. Open inlet steam valve and
turn #28 adjusting screw clockwise.
If fluid does not appear at #31A,
pilot valve is clogged.
Close all valves and remove fitting
#31C. Open bypass valve around
PRV. If fluid appears out of
diaphragm casing at #31C,
diaphragm has failed.
Throttle downstream valve located
downstream of sensing line. If
desired, pressure can be reached
after throttling valve. PRV is too
small.
Turn #28 adjusting screw counter
clockwise.
Remove and check.
Clean.
Clean.
Disassemble and clean #19 pilot
valve seat. Also check #17 screen.
1) Close inlet and outlet steam
valves
2) Turn #28 adjusting screw
counterclockwise until loose.
3) Remove copper tubing at #31A
fitting and #32 tee.
4) Open inlet steam valve.
5) If fluid appears at 31A, proceed
to solution #1.
6) If fluid appears at 31B, proceed
to solution #2 and also see D
below.
7) If fluid does not appear at either
part, proceed to E below.
If valve fails test at #31B (as
described above in item 6) check
while assembled.
Close and listen with stethoscope.
Break union and open valve.
Refer to Figure 1-1.
1) Tighten or loosen adjusting screw
to flush out dirt. If valve still
leaks, clean it.
Listen to steam traps with
stethoscope.
Check #31B and #31C.
Refer to Figure 1-1.
Refer to Figure 1-1.
Refer to Figure 1-1.
Recalculate load.
Listen with stethoscope or see if it
is hot.
3
Dismantle and clean.
Install proper coupler.
Disassemble and replace #13 main
diaphragm.
Resize and install larger valve.
Readjust.
Clean.
2) Disassemble and remove main
valve (it will lift out easily). If it
appears shiny at one point, apply
lapping compound and lap the
valve and seat. (See Bulletin
AY-768).
Clean.
Repair
Clean
Install sensing line as shown on
installation drawing.
Repair faulty traps.
Remove and clean.
Install sensing pipe at another
location.
Slant pipe away from PRV.
Relocate.
Change valve or add silencer to
outlet of PRV.
Use two stage reduction.
Repair.
Relocate.
GP-11 Pressure Reducing Valve Integral Mount Pilot
For Steam Service
(7) Main
Valve Seat
31A
Fitting
a
Packing
Plug
Adjusting Screw (28)
Tube
Name Plate
Plug
31B
Fitting
Lock Nut (29)
Parker Rivet
(1) Body
Plug
Spring Housing
Bolt
32 Tee
Top Plate
(10)
Guide
Tube
Stud Bolt
Gasket
Adjusting Spring (25)
Nut
Bottom Plate (26)
31C
Fitting
Diaphragm Case
Spring Retainer (27)
Pilot Diaphragm
Gasket
Nut
Pilot Valve Seat (19)
(9) Valve Stem
Stem
Nut
Spring
Cap
(11) Retainer
Gasket
Bolt
Plug
Packing
Pilot Body (2)
(13) Main Diaphragm
Downstream
Sensing Port
Gasket
a
Gasket
Screen (17)
Spring Retainer (16)
Diaphragm
Case
Spring (15)
Main Valve (6)
Plug
Bolt
Figure 4-1
Armstrong-Yoshitake, Inc.
816 Maple Street, Three Rivers, Michigan 49093/ Phone: (616) 273-1415
AY-710-A
10/94
TRP
Steam Traps \ Humidifiers \ Steam Coils \ Valves
Printed in U.S.A.

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