Yoshitake GD-15 is a low-noise pressure reducing valve for individual water supply to complex housing. It can highly maintain the stable reduced pressure against a variation of supply water pressure. Incorporated strainer and the compact and light weight design ensure easy piping. GD-15C is equipped with a check valve to prevent back-flow to the main water supplying pipe.

Features

• Removed noise. Can be used even late at night.
• Water supplying pressure has already been adjusted at 0.2 MPa (standard setting), so no need to adjust at sight.
• Pressure balance structure can keep the reduced pressure at a constant level without being affected by inlet pressure.
• Incorporated strainer prevents foreign substances such as dirt, scale and sand from flowing to the outlet side.
• Easy maintenance because strainer and strainer cap are integrated and detachable without any tool.
• Closed structure prevents fluid flowing to the outside even when the diaphragm is damaged or broken.
• Pipes can be installed either horizontally or vertically.

Specifications

Specification	GD-15, GD-15C
Nominal size	15A, 20A
Application	City water
Inlet pressure	0.1-1.0 MPa
Reduced pressure	0.05~0.25 MPa [Standard setting: 0.2 MPa]
Minimum differential pressure	0.03 MPa
Maximum pressure reduction ratio	10:1
Minimum adjustable flow rate	0.5 L/min
Working temperature	5-60°C*
Rated flow rate (15A)	25 L/min (40 L/min when differential pressure is 0.10 MPa or more)
Rated flow rate (20A)	30 L/min (50 L/min when differential pressure is 0.10 MPa or more)
Material (Body)	Bronze (NPb-treated)
Material (Spindle)	Brass
Material (Valve)	Synthetic rubber
Material (Diaphragm)	EPDM (with fabric)
Connection	JIS Rc screwed
Outlet withstand pressure	1.2 times of maximum outlet pressure

Notes

• The closing pressure of the check valve for GD-15C is 0.005 MPa or less.
• The strainer is 40 mesh.
• An incombustible material is used for heat insulating material.
• Please contact us for using at hot water supplying side.

Dimensions and Weights

Nominal size	d	Weights (kg)
15A	Rc 1/2	0.87
20A	Rc 3/4	0.87

Dimensions of the Heat Insulating Material

Materials and Structure

No.	Name of Parts	Material	Q.TY
1	Body	Bronze	1
2	Spindle	Brass	1
3	O Ring	EPDM	1
4	Diaphragm	EPDM	1
5	Diaphragm Shell	Carbon Steel Sheet	1
6	Washer	Carbon Steel Sheet	1
7	Spring Plate	Brass	1
8	Disc	EPDM & Stainless Steel	1
10	Valve Cap	Bronze	1
11	O Ring	EPDM	1
12	O Ring	EPDM	1
13	Spring Cover	Carbon Steel	1
14	Set Screw	Stainless Steel	6
15	Spring	Piano Wire	1
16	Spring Plate	Brass	1
17	Adjusting Screw	Brass	1
18	Strainer	Stainless Steel & POM	1
19	O Ring	EPDM	1
20	Strainer Cap	Bronze	1
21	Label	Resin	1
22	Washer	Stainless Steel	1
23	Nut	Stainless Steel	1
24	Cap	Steel	1
25	O Ring	NBR	1
30	Label	Polyester	1

Performance Data

Pressure Characteristic Chart

This chart shows variation in reduced pressure when the inlet pressure of 0.5 MPa is changed between 0.18 MPa and 1.0 MPa, while the reduced pressure is set at 0.15 MPa.

Flow Characteristic Chart

Noise Characteristic Chart

• Distance from the sample valve to the microphone: 15cm
• Background noise: 35 dB(A)

Precautions During Installation

Installation Cautions

1. Install the valve so as to make the arrow on body points the same direction as flow.
2. Pipes can be installed either horizontally or vertically.
3. Maintenance will be easier by installing union joint in front and after the pressure reducing valve.
4. Please be sure to remove foreign substances and scales from inside of the piping before connecting the product to the piping.
5. Since the pressure has already been set, please do not touch the adjusting screw unless changing the set pressure. Please adjust pressure in the indicated range on the label, when changing the set pressure.
6. Please clean up the strainer regularly, because the water supply decrease as foreign substance accumulates inside the strainer. Especially foreign substance accumulates at the first plumbing, so check the strainer soon after starting water supplying.
7. GD-15 needs 50 mm (GD-15C 55 mm) or more space for checking the strainer.
8. Caution when installing Polyvinyl chloride pipe: Synthetic rubber could be attacked by glue of polyvinyl chloride pipe. Please be careful not to flow glue in to the valve.
9. It is recommended to use bronze or stainless steel nipples on the outlet side piping of the product because corrosion of steel pipe edge will increase yearly. The rust may clog the sensing port of the product and decreases the water flow.

How to Adjust the Pressure

Adjustment Warning

When adjusting the pressure, please follow to the procedure as follows. Otherwise inappropriate adjustment may cause water hammer or hunting and break important parts.

1. Gradually open the inlet side stop valve fully and slightly open the outlet side stop valve to allow a small amount of flow.
2. Remove the cap. Checking the pressure gauge, turn the adjusting screw to adjust the reduced pressure to a desired level.
   • The reduced pressure decreases when the adjusting screw is turned clockwise.
   • The reduced pressure increases when the adjusting screw is turned counterclockwise.
3. Gradually open the outlet side stop valve fully.
4. After reduced pressure adjustment, attach the cap.

Piping Example