754-D 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) Globe Valve Minimum of 10 Outlet Pipe Diameters from Last Valve or Fitting By-Pass Safety Relief Valve Armstrong Stainer GD-24 Minimum of 10 Inlet Pipe Diameters from PRV to First Turn Minimum of 20 Outlet Pipe Diameters from PRV to First Turn Note: 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 information. 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 position. Troubleshooting Guide Problem Causes Solutions The intended pressure cannot be obtained. Inlet pressure is too low or too high. Adjust the pressure to the appropriate level. 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 required. Replace the valve with a suitable size valve. 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 level. 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. Disassembly 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) Lock 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) Screw Lock Nut (12) Diaphragm (9) Hanger (7) Nameplate Cover Bolt (19) Seal Nut (20) Body (1) Spring Chamber (2) Pressure Gauge Valve Seat (5) Set Screw (14) Flat Washer (13) Disc (6) Valve (4) Notes to Reassembly Reassemble in the reverse order of disassembly. Lock Washer (28) Spring Plate (10) Spring (21) Adjusting (17) Spring 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 754-D 6/14 armstronginternational.com Printed in U.S.A.
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