Armstrong GD-24 is an industrial-grade pressure reducing valve for non-potable water systems. It is lightweight, compact, and economical. The valve comes with screwed connections and will mount in any position, requiring no external sensing lines. Its bronze body and high-temperature diaphragm are suitable for hot or cold process water service. The valve, seat, and diaphragm are renewable in line. It features an external adjusting screw with a lock and provides ANSI Class IV shutoff.

WARNING

Illegal for potable water service per SDWA section 1417 (As Amended). For Non-Potable Water Service Only.

Specifications

Application	Maximum Pressure psig (bar)	Reduced Pressure Range psig (bar)	Minimum Differential psig (bar)	Maximum Temperature °F (°C)	Body Material	Main Valve	Valve Seat	Diaphragm
Hot or Cold Water	230 (16)	7 - 80 (0.48 - 5.5)	7 (0.48)	175 (79)*	Cast Bronze ASTM 584	Stainless Steel AISI 304	Stainless Steel AISI 304	NBR**

*With Viton® diaphragm maximum temperature is 210°F (99°C).**Viton optional.

Capacities — Water

ΔP (psig)	1/2"	3/4"	1"	1-1/4"	1-1/2"	2"	ΔP (bar)	15mm	20mm	25mm	32mm	40mm
7	4	5	8	11	19	26	0.5	15	20	30	40	70
10	5	6	9	13	22	32	0.7	18	24	36	48	84
15	6	8	12	15	27	39	1.0	22	29	44	59	103
25	8*	10	15	20	35	50	1.7	30*	38	57	76	132
50	11	14*	21	28	49	71	3.4	40	53*	80	107	187
75	13	17	26*	35	61*	87	5.2	49	66	98*	131	231*
100	15	20	30	40*	70	100*	6.9	57	76	114	151*	265
125	17	22	34	45	78	112	8.6	63	85	127	169	296
150	18	24	37	49	86	122	10.3	70	93	139	185	325
175	20	26	40	53	93	132	12.0	75	100	150	200	351
200	21	28	42	57	99	141	13.8	80	107	161	214	375

INFO

*At flows greater than this, velocities will exceed 10 ft/sec and pipe erosion could occur. NOTE: Maximum pressure reduction ratio 10:1.

Dimensions and Weights

Size	1/2" (15mm)	3/4" (20mm)	1" (25mm)	1-1/4" (32mm)	1-1/2" (40mm)	2" (50mm)
L	3-1/4" (83mm)	3-1/2" (89mm)	4" (102mm)	4-3/4" (121mm)	6" (152mm)	7-1/4" (184mm)
H1	1-3/4" (45mm)	2" (51mm)	2-1/2" (64mm)	3-1/4" (83mm)	3-1/2" (89mm)	4-1/2" (115mm)
H	7-3/4" (197mm)	8-1/2" (216mm)	9-5/8" (245mm)	11-1/4" (286mm)	13-1/2" (343mm)	16" (407mm)
Weight	4 lb (1.8 kg)	5-1/4 lb (2.4 kg)	7-1/4 lb (3.3 kg)	10-3/8 lb (4.7 kg)	18 lb (8.2 kg)	31-1/2 lb (14.3 kg)
Cv	1.5	2	3	4	7	10

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.
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.
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.

Startup and Adjustment Procedures

WARNING

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.
2. Loosen the lock nut on the adjusting screw to allow adjustment. Relieve the adjusting spring.
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.
4. Slowly turn the adjusting screw clockwise until the desired pressure is obtained on the downstream pressure gauge.
5. Slowly open the outlet valve to the fully open position.
6. Adjust pressure again after system stabilizes. Turning the adjusting screw; Clockwise increases pressure and Counterclockwise decreases pressure.
7. Tighten the adjusting screw lock nut after adjustment is completed.

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.
	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 reduced pressure is higher than the specified level.	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.
Abnormal noise is heard.	Excessive air is in the system.	Install an air vent.
	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.
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.

Notes to Reassembly

Reassemble in the reverse order of disassembly.

Orient Hanger Opening In Line With Valve Body Inlet/Outlet Connections (As Shown)