PN25
The Armstrong GD-30 and GD-30S are compact, high-performance direct-acting pressure reducing valves. Economical to buy and use, they are ideal for low to moderate flow applications where an accuracy of +/-10% is acceptable. The GD-30 and GD-30S are well suited for laundry and dry cleaning equipment, hospital equipment, tire molds, humidifiers, small heaters, and applications in food processing. They provide tight shutoff for dead-end service on steam, featuring a turndown ratio of 10:1 and ANSI Class IV shutoff.
Specifications
| Model Number | Inlet Pressure psig (barg) | Reduced Pressure psig (barg) | Spring Color | Minimum Differential psig (barg) | Application | Maximum Temp. °F (°C) | Body Material | Valve/Seat Material | Bellows Material |
|---|---|---|---|---|---|---|---|---|---|
| GD-30 | 15 - 250 (1 - 17) | 3 - 15 (0.21 - 1.0) 7 - 60 (0.5 - 4.0) 50 - 140 (3.4 - 9.6) | Yellow Blue Green | 7 (0.48) | Steam, Air, Non-Corrosive Gases | 410 (210) | Cast Bronze ASTM B584 | Stainless Steel AISI 440/304 | Phosphor Bronze ASTM B103* |
| GD-30S | 15 - 300 (1 - 20) | 3 - 15 (0.21 - 1.0) 7 - 60 (0.5 - 4.0) 50 - 140 (3.4 - 9.6) | Yellow Blue Green | 7 (0.48) | Steam, Air, Non-Corrosive Gases | 430 (220) | Stainless Steel AISI 316 | Stainless Steel AISI 316L | Stainless Steel AISI 316L |
*Stainless steel optional.
Dimensions and Weights
| Connection Size | L in (mm) | H1 in (mm) | H in (mm) | Weight lb (kg) | Cv |
|---|---|---|---|---|---|
| 1/2" (15 mm) | 3-1/8 (80) | 2 (47) | 7-1/2 (191) | 4-1/4 (1.9) | 1.3 |
| 3/4" (20 mm) | 3-3/8 (85) | 2 (47) | 7-1/2 (191) | 4-1/4 (1.9) | 1.5 |
| 1" (25 mm) | 3-3/4 (95) | 2 (47) | 7-1/2 (191) | 4-1/2 (2.0) | 2.5 |
| 1-1/2" (40 mm)* | 5-1/2 (140) | 3 (77) | 12-1/8 (307) | 21-3/8 (9.7) | 5.6 |
| 2" (50 mm)* | 5-7/8 (150) | 3 (77) | 12-1/8 (307) | 22 (10) | 8.5 |
*GD-30S available in 1/2", 3/4", and 1" only.
Capacities — Steam
| Inlet psig (barg) | Outlet psig (barg) | 1/2" (15mm) | 3/4" (20mm) | 1" (25mm) | 1-1/2" (40mm) | 2" (50mm) |
|---|---|---|---|---|---|---|
| 15 (1.0) | 7 (0.5) | 49 (22) | 56 (25) | 92 (42) | 198 (90) | 297 (-) |
| 20 (1.4) | 13 (0.9) | 53 (24) | 61 (28) | 105 (48) | 216 (98) | 331 (-) |
| 7 (0.5) | 42 (19) | 55 (25) | 63 (35) | 180 (82) | 264 (-) | |
| 30 (2.0) | 23 (1.6) | 62 (28) | 71 (32) | 112 (51) | 242 (110) | 408 (-) |
| 15 (1.0) | 53 (24) | 60 (27) | 101 (46) | 209 (95) | 309 (-) | |
| 3 (0.2) | 33 (15) | 40 (18) | 60 (27) | 139 (63) | 216 (-) | |
| 40 (2.8) | 32 (2.2) | 99 (45) | 121 (55) | 187 (85) | 407 (185) | 617 (-) |
| 20 (1.4) | 79 (36) | 97 (44) | 159 (72) | 330 (150) | 517 (-) | |
| 4 (0.3) | 40 (18) | 55 (25) | 77 (35) | 159 (72) | 264 (-) | |
| 50 (3.4) | 40 (2.8) | 130 (59) | 143 (65) | 242 (110) | 539 (245) | 837 (-) |
| 20 (1.4) | 99 (45) | 115 (52) | 187 (85) | 407 (185) | 628 (-) | |
| 5 (0.3) | 48 (22) | 62 (28) | 88 (40) | 193 (88) | 297 (-) | |
| 60 (4.0) | 48 (3.3) | 137 (62) | 154 (70) | 265 (120) | 584 (265) | 899 (-) |
| 40 (2.8) | 150 (68) | 165 (75) | 289 (131) | 617 (280) | 969 (-) | |
| 18 (1.2) | 90 (41) | 104 (47) | 170 (77) | 374 (170) | 584 (-) | |
| 6 (0.4) | 55 (25) | 73 (33) | 99 (45) | 220 (100) | 331 (-) | |
| 80 (5.5) | 64 (4.4) | 176 (80) | 205 (93) | 342 (155) | 738 (335) | 1168 (-) |
| 54 (3.7) | 187 (85) | 225 (102) | 353 (160) | 782 (355) | 1201 (-) | |
| 23 (1.6) | 121 (55) | 137 (62) | 220 (100) | 489 (222) | 749 (-) | |
| 8 (0.5) | 60 (27) | 77 (35) | 108 (49) | 231 (105) | 363 (-) | |
| 100 (6.9) | 80 (5.5) | 203 (92) | 242 (110) | 397 (180) | 863 (392) | 1355 (-) |
| 66 (4.5) | 225 (102) | 262 (119) | 437 (198) | 958 (435) | 1465 (-) | |
| 40 (2.8) | 198 (90) | 231 (105) | 375 (170) | 837 (380) | 1278 (-) | |
| 10 (0.7) | 68 (31) | 79 (36) | 132 (60) | 297 (135) | 473 (-) | |
| 120 (8.3) | 96 (6.6) | 231 (105) | 276 (125) | 452 (205) | 991 (450) | 1520 (-) |
| 70 (4.8) | 276 (125) | 311 (141) | 518 (235) | 1168 (530) | 1818 (-) | |
| 45 (3.1) | 240 (109) | 267 (121) | 450 (204) | 980 (445) | 1509 (-) | |
| 12 (0.8) | 110 (50) | 121 (55) | 198 (90) | 462 (210) | 705 (-) | |
| 150 (10.3) | 120 (8.3) | 287 (130) | 333 (151) | 551 (250) | 1212 (550) | 1862 (-) |
| 85 (5.9) | 364 (165) | 421 (191) | 705 (320) | 1531 (695) | 2369 (-) | |
| 55 (3.8) | 298 (135) | 353 (160) | 595 (270) | 1278 (580) | 2005 (-) | |
| 15 (1.0) | 132 (60) | 165 (75) | 254 (115) | 562 (255) | 848 (-) | |
| 180 (12.4) | 140 (9.7) | 408 (185) | 485 (220) | 794 (360) | 1719 (780) | 2677 (-) |
| 115 (8.0) | 430 (195) | 507 (230) | 860 (390) | 1829 (830) | 2832 (-) | |
| 70 (4.8) | 386 (175) | 430 (195) | 739 (335) | 1619 (735) | 2501 (-) | |
| 18 (1.2) | 165 (75) | 187 (85) | 309 (140) | 683 (310) | 1035 (-) | |
| 200 (13.8) | 140 (9.7) | 461 (209) | 518 (235) | 871 (395) | 1983 (900) | 3063 (-) |
| 115 (8.0) | 474 (215) | 540 (245) | 904 (410) | 2005 (910) | 3085 (-) | |
| 80 (5.5) | 430 (195) | 496 (225) | 827 (375) | 1818 (825) | 2810 (-) | |
| 20 (1.4) | 209 (95) | 242 (110) | 386 (175) | 848 (385) | 1300 (-) | |
| 225 (15.5) | 140 (9.7) | 485 (220) | 573 (260) | 948 (430) | 2060 (935) | 3195 (-) |
| 115 (8.0) | 496 (225) | 584 (265) | 961 (436) | 2071 (940) | 3207 (-) | |
| 85 (5.9) | 463 (210) | 540 (245) | 904 (410) | 1983 (900) | 3063 (-) | |
| 23 (1.6) | 254 (115) | 298 (135) | 496 (225) | 1079 (490) | 1675 (-) | |
| 250 (17.2) | 140 (9.7) | 525 (238) | 606 (275) | 1014 (460) | 2226 (1010) | 3438 (-) |
| 120 (8.3) | 551 (250) | 584 (265) | 1038 (471) | 2248 (1020) | 3471 (-) | |
| 70 (4.8) | 463 (210) | 529 (240) | 893 (405) | 1939 (880) | 2997 (-) | |
| 25 (1.7) | 276 (125) | 320 (145) | 529 (240) | 1146 (520) | 1796 (-) | |
| GD-30S Only | ||||||
| 275 (18.9) | 140 (9.7) | 529 (240) | 613 (278) | 1023 (464) | - | - |
| 120 (8.3) | 529 (240) | 613 (278) | 1023 (464) | - | - | |
| 70 (4.8) | 470 (213) | 542 (246) | 902 (409) | - | - | |
| 28 (1.9) | 295 (134) | 344 (156) | 562 (255) | - | - | |
| 300 (20.0) | 140 (9.7) | 529 (240) | 613 (278) | 1023 (464) | - | - |
| 100 (6.9) | 529 (240) | 613 (278) | 1023 (464) | - | - | |
| 70 (4.8) | 478 (217) | 551 (250) | 926 (420) | - | - | |
| 30 (2.7) | 309 (140) | 359 (163) | 595 (270) | - | - |
Note: Capacities are in lb/hr (kg/hr). For air capacities scfm, multiply steam capacities (lb/hr) by 0.36. For air capacities m3/hr, multiply steam capacities (kg/hr) by 1.35. Maximum pressure reduction ratio 10:1.
Installation Instructions
- An Armstrong Inverted Bucket Steam Trap is recommended to drain condensate at the inlet of the Pressure Reducing Valve (PRV). A Liquid Drainer is recommended for air service.
- An Armstrong Y-Strainer (20-100 mesh, depending on system dirt) should be installed before the PRV to reduce the chance of dirt fouling.
- Pressure gauges should be installed before and after the PRV.
- If the system cannot be turned off to service the PRV, piping a by-pass line with a high-quality globe valve around the PRV will allow manual system operation while the PRV is being serviced.
- Do not install quick opening or closing valves downstream of the PRV.
- Install the PRV with the flow in the direction of the arrow on the body.
WARNING
If a safety valve is installed as a protective device on the outlet side, a discharge pipe must be installed at the outlet of the safety valve and led to a safe place for steam discharge to prevent burns.
Start-Up and Adjustment Procedures
Improper adjustment of the pressure reducing valve may cause hunting, scale problems, water hammer, etc., and damage to the valve itself. Damaged pressure gauges, leakage or opening of a bypass valve, or clogging of an inlet strainer may cause problems similar to that of a malfunctioning reducing valve.
Adjust the valve as follows:
- Close the gate valves before and after the pressure reducing valve. Open the globe valve slowly in the bypass line and blow down the inlet piping. Adjust the opening of the bypass valve so the safety valve does not blow. After blowing the system down, close the bypass valve.
- Slowly open the inlet side gate valve to the fully open position, and partially open the outlet valve so only a small amount of steam or air can pass.
- To increase the downstream pressure, place your hand on the top of the adjusting handle and pull vertically up. When in the fully up position turn the handle clockwise until the desired pressure is obtained on the downstream pressure gauge.
- Release the handle and it will automatically retract which will lock the adjusting handle in place.
- Slowly open the outlet valve to the fully open position.
Troubleshooting
| Problem | Causes | Solutions |
|---|---|---|
| The desired pressure cannot be obtained. | The inlet pressure is too low or high. The sensing port of the outlet pressure is clogged with foreign matter. The valve size is smaller than what is required. The adjustment is not appropriate. The inlet strainer is clogged by foreign substance. The pressure gauge is not functioning properly. | Change the pressure to the appropriate level. Disassemble and clean the sensing port. Change the valve size to the appropriate one. Readjust according to the adjustment procedure. Disassemble and clean the strainer. Replace the pressure gauge. |
| The outlet pressure rises higher than the specified pressure. | The valve or valve seat is contaminated by foreign substance. The by-pass valve is leaking. | Disassemble and clean the valve or the seat. Repair or replace the by-pass valve. |
| Abnormal noise is heard. | The reducing ratio is excessively large. Water hammer (for steam service). There is a fast closing valve near the PRV. | Reduce pressure by staging with second PRV. Install a steam trap at the reducing valve inlet. Provide as long a distance as possible between the two valves. |
Maintenance and Disassembly
DANGER
Eliminate pressure from inside the valve. Make sure the valve is completely free from pressure and cold before handling. Equipment under pressure and operating temperatures > 100°C can cause severe burns.
Disassembly (1/2" to 1")
- Eliminate pressure from inside the valve. Make sure the valve is completely free from pressure.
- Pull up and turn the handle (4) in the direction (counterclockwise) as shown on the nameplate of the handle to make the spring (12) free (not loaded).
- Remove the bolts (15) and take away the spring housing (2) (the handle cannot be disassembled). Take out the spring (12), bellows (10) and valve rod (8).
- Unscrew (counterclockwise) the cap (3) and take out the spring (13), screen (9) and valve (7) from the body (1).
Disassembly (1-1/2" to 2")
- Eliminate pressure from inside the valve. Make sure the valve is completely free from pressure.
- Pull up and turn the handle (22) in the direction (counterclockwise) as shown on the nameplate of the handle to make the adjusting spring (13) free (not loaded).
- Remove the bolts (19) and take away the spring housing (2) (the handle cannot be disassembled). Take out the adjusting spring (13), bellows (9) and spindle (6).
- Unscrew (counterclockwise) the cap (3) and take out the main valve spring (7), screen (8) and spindle (5) from the body (1).
Reassembly
- Check all parts to make sure they are in good condition before putting back together.
- Lap valve/spindle and valve seat with 1000 grit lapping compound if needed to ensure no leakage.
- Reassemble in reverse order as disassembly. Note: Replace all gaskets where disassembly is required.
