Model GD-24
Pressure Reducing Valve
Installation, Operation and
Maintenance Instructions
*Illegal for potable water service per SDWA Section 1417 (as amended).
Typical Single Stage
Reduction Installation
(For Water)
Minimum of 10 Outlet
Pipe Diameters from
Last Valve or Fitting
Safety Relief
Minimum of 10 Inlet
Pipe Diameters from
PRV to First Turn
Minimum of 20 Outlet
Pipe Diameters from
PRV to First Turn
Safety Relief Valve to be set at
10 psi higher or 10% higher than
the downstream pressure, whichever
is greater.
This bulletin should be used by experienced personnel as a guide to the installation of the Model GD-24 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
Installation Instructions
1. An Armstrong “Y” strainer (20 – 100 mesh, depending
on liquid quality) should be installed before the PRV
to reduce the chance of dirt fouling.
2. Pressure gauges should be installed before and after
the PRV.
4. Do not install quick opening or closing valves
downstream of PRV.
5. Install the PRV with the flow in the direction of the
arrow on the body.
3. Piping a bypass line with a globe valve around the
PRV will allow system operation while the PRV is
being serviced. Install only if fluid cannot be shut-off
to service PRV.
Startup and Adjustment Procedures
Improper adjustment of the pressure reducing valve may cause hunting, improper control, and possible damage to the
valve itself. Adjust the valve as follows:
1. Close the gate valves before and after the PRV.
Open the bypass valve slowly in the bypass line
and blow the system down. Care should be taken
not to open the bypass completely to prevent the
safety relief valve (if installed) from popping off. After
blowing down the system, close the bypass valve.
4. Slowly turn the adjusting screw clockwise until the
desired pressure is obtained on the downstream
pressure gauge.
2. Loosen the lock nut on the adjusting screw to allow
adjustment. Relieve the adjusting spring. See
Figure 2-1.
6. Adjust pressure again after system stabilizes.
Turning the adjusting screw; Clockwise increases
pressure and Counterclockwise decreases pressure.
3. Slowly open the inlet side gate valve to the fully
open position, and partially open the outlet valve so
only a small amount of fluid can pass.
7. Tighten the adjusting screw lock nut after adjustment
is completed.
5. Slowly open the outlet valve to the fully open
Troubleshooting Guide
The intended pressure
cannot be obtained.
Inlet pressure is too low or too high.
Adjust the pressure to the appropriate
The inlet strainer is clogged.
Disassemble and clean the strainer.
The adjustment is not appropriate.
Readjust the valve according to the
adjusting procedure.
(See start-up procedure.)
The pressure gauge is out of order.
Replace the pressure gauge.
The valve size is smaller than what is
Replace the valve with a suitable size
The valve and valve seat are contaminated
by a foreign substance.
Disassemble and clean the valve body
and the valve seat.
The bypass valve is leaking.
Repair or replace the bypass valve.
The diaphragm is ruptured.
Replace the diaphragm.
Excessive air is in the system.
Install an air vent.
The reduced pressure is
higher than the specified
Abnormal noise is heard.
The valve size is larger than what is required. Install the correct size valve.
A quick operating valve is installed near the
pressure reducing valve (i.e. solenoid valve).
Provide as much distance as possible
between the two valves.
The GD-24 PRV is composed of two components: body and spring chamber.
1. To remove the spring chamber, loosen the lock nut, turn the adjusting screw counter-clockwise until it can be turned easily by your fingers, and then remove the cover bolts.
2. To remove the diaphragm, detach
the diaphragm from the body
flange surface and then loosen the
hexagon nut on top of the disk thrust
plate for disassembly.
Figure 2-1
Nut (16)
Washer (15)
Disk Thrust
Plate (8)
Orient Hanger Opening
In Line With Valve Body
Inlet/Outlet Connections
(As Shown)
3. Remove body cap on the bottom of the valve. Once off, take out the O-ring and valve spring.
4. To remove the valve, turn the valve
counter-clockwise using the slots in
the bottom of the valve to unscrew it
from the hanger.
Adjusting (11)
Lock Nut (12)
Diaphragm (9)
Hanger (7)
Bolt (19)
Seal Nut (20)
Body (1)
Spring Chamber (2)
Valve Seat (5)
Set Screw (14)
Flat Washer (13)
Disc (6)
Valve (4)
Notes to Reassembly
Reassemble in the reverse order of
Washer (28)
Spring Plate (10)
Spring (21)
Adjusting (17)
O-Ring (18)
Cap (3)
Armstrong Steam and Condensate Group, 221 Armstrong Blvd., Three Rivers, Michigan 49093 - USA Ph: (269) 279-3600 Fax: (269) 278-6555
Printed in U.S.A.
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF