Yoshitake GD-43N-20 is a direct type pressure reducing valve specifically designed for cold and hot water systems. It conforms to the Japanese Water Supply Act (JWWA) and utilizes a pressure balance structure to maintain a constant reduced pressure regardless of inlet pressure fluctuations. The valve is constructed with stainless steel wetted parts to improve corrosion resistance.

Features

• Space saving and resource saving are achieved (used materials are shown on the body and lower cap, thus separate collection of parts for resource recycling is easy).
• Stainless steel (SCS14A and SUS316) is used for wetted parts, improving corrosion resistance.
• PTFE covers the diaphragm contact surface to fluid, making the diaphragm less liable to deteriorate and highly durable.
• Special fluorine-contained rubber parts are resistant to corrosion.
• Pressure balance structure can keep the reduced pressure at a constant level without being affected by inlet pressure.
• Closed structure keeps fluid from flowing to outside.

Specifications

Specification	Value
Model	GD-43N-20
Application Fluid	Cold and hot water
Inlet Pressure	0.07~2.0 MPa
Reduced Pressure	Spring A (yellow): 0.02~0.1 MPa Spring B (red): 0.1~0.25 MPa Spring C (black): 0.25~0.5 MPa
Minimum Differential Pressure	0.05 MPa
Maximum Pressure Reduction Ratio	10:1
Operating Temperature	5~90°C
Connection	JIS 20K RF Flanged
Body Material	Cast Stainless steel (SCS14A)

INFO

Models conforming to the Japanese Water Supply Act are the GD-41N and GD-43N series.

Dimensions and Weights

Size	D	C	g	t	f	n-h	Weight (kg)
15A	95	70	51	14	1	4-15	2.8
20A	100	75	56	16	1	4-15	3.0
25A	125	90	67	16	1	4-19	4.0

Nominal Size Selection

For Cold/hot water

Nominal size calculation example

Determine the nominal diameter for a pressure reducing valve of primary pressure 0.5 MPa, secondary pressure 0.3 MPa, flow rate 10 L/min. On the bottom horizontal line of the figure above, start at the point 0.2 (pressure difference between upstream and downstream of the valve 0.2 MPa) and go straight up along the line to the point A where the line crosses the flow rate 10 L/min line. This intersecting point A is between nominal diameter 15A and 20A. Select the larger one, 20A, which is the required nominal diameter.

Precautions during installation and operation

DANGER

• When installing a safety valve at the outlet side of the pressure reducing valve, connect a blow-off pipe to the outlet of the safety valve to lead the possible discharged fluid to a safety location.
• Never touch the pressure reducing valve with bare hands while any hot fluid flows.

WARNING

• Be sure to install a strainer at the inlet side of the pressure reducing valve. Ingress of foreign substances or scale leads to malfunction. It is recommended to use a strainer of 60 mesh or more.
• Installing a safety valve at the outlet side of the pressure reducing valve to protect the equipment.
• Before connecting the pressure reducing valve to the piping, remove foreign materials from the piping.