The Yoshitake GD-27-NE is a direct-type pressure reducing valve designed for cold and hot water applications. It maintains a constant reduced pressure regardless of inlet pressure fluctuations, thanks to its balanced pressure structure. Featuring a closed design to keep fluid contained even if the diaphragm is damaged, and constructed with NPb-treated cast bronze wetted parts, the GD-27-NE ensures safe, rust-free operation.

Features

• Wetted parts are made of corrosion-resistant material (NPb-treated cast bronze) to prevent rusty water.
• Low noise design.
• Pressure balance structure keeps the reduced pressure constant without being affected by inlet pressure.
• Closed structure keeps fluid inside even if the diaphragm is damaged.
• Easy maintenance and inspection by disassembling the upper side only.
• Compact and lightweight design makes piping works easy.

Specifications

Specification	Value
Application	Cold and hot water
Inlet pressure	1.0 MPa or less
Reduced pressure	(A) 0.05-0.35 MPa (B) 0.30-0.70 MPa
Minimum differential pressure	0.05 MPa
Maximum pressure reduction ratio	10:1
Application temperature	5~90℃
Body / Valve seat	Cast Bronze (NPb-treated)
Valve disc	FKM
Diaphragm	EPDM
Connection	JIS 10K FF flanged

INFO

A strainer (40 mesh) is incorporated in sizes 25A to 50A. Sizes 65A to 100A do not include a strainer. Pressure gauge connection port is JIS R1/8 (maximum temperature 45℃; use a siphon tube if higher). Conformant to the Japanese Water Supply Act.

Dimensions and Weight

Nominal size	L (mm)	H (mm)	H1 (mm)	Weight (kg)
25A	160	170	41	5.1
32A	200	224	57	7.5
40A	200	224	57	7.7
50A	220	239.5	61	10.9
65A	220	329	77	20.0
80A	230	345	82	22.0
100A	270	412	94	33.0

Operating Principle

The spring is compressed by the adjusting screw, pushing the diaphragm down, and thereby opening the disc directly connected to it. Fluid from the inlet side flows out from the upper part of the disc to the outlet side, passes through the reduced pressure detection hole, and is led to the bottom of the diaphragm. The load of the spring and the reduced pressure act on the diaphragm, maintaining balance and regulating the valve opening to keep the reduced pressure constant.

Characteristics and Flow Rate

Rated Flow Table (Differential pressure ≥ 0.15 MPa)

Nominal size	25A	32A	40A	50A	65A	80A	100A
Rated flow (L/min)	60	100	150	250	300	450	700

Flow Rate Charts (Differential pressure < 0.15 MPa)

Nominal size 25A to 50A:

Nominal size 65A to 100A:

Noise Characteristic Chart

Pressure Characteristic Chart

Shows variation in reduced pressure when the inlet pressure of 0.6 MPa is changed between 0.15 MPa and 1.0 MPa while the reduced pressure is set at 0.1 MPa.

Flow Characteristic Chart

Offset pressure:

Nominal size	Pressure range	Reduced pressure range	Offset pressure
25-100A	A	0.05-0.35 MPa	Within 0.05 MPa
25-100A	B	0.30-0.70 MPa	Within 0.10 MPa

Installation

Piping Example

Precaution for Installation

1. Before installing, completely remove foreign substances and scale from the piping. Ingress of foreign substances, scale or seal agent leads to valve leakage or malfunction.
2. Be sure to install a strainer at the inlet side of the product for nominal sizes 65A to 100A (40 mesh or more recommended).
3. Install a safety relief valve for equipment protection at the outlet side.
4. Install pressure gauges at both sides.
5. Keep quick-operating valves (e.g., solenoid valves) at least 3 meters away.
6. The product can be installed horizontally or vertically.

Adjusting Procedure

1. Close the stop valves at both sides and blow out fluid using a bypass line.
2. Fully open the inlet stop valve slowly, and open the outlet stop valve slightly.
3. Remove the domed cap nut and turn the adjusting screw while watching the outlet pressure gauge:
   • Turn clockwise to increase reduced pressure.
   • Turn counterclockwise to decrease reduced pressure.
4. Fully open the outlet stop valve slowly.
5. Tighten the domed cap nut after adjustment.

Maintenance and Troubleshooting

Troubleshooting

Trouble	Cause	Remedy
Abnormal pressure rises at outlet	Foreign substances on disc/seat, damaged O-ring or diaphragm, or bypass valve leakage.	Disassemble and clean/replace damaged parts or repair bypass valve.
Reduced pressure does not reach value	Improper working pressure, undersized valve, clogged strainer, or improper adjustment.	Correct pressure/sizing, readjust, or clean strainer.
Outside leakage	Loosened bolts/cap or damaged O-ring.	Tighten bolts/cap or replace O-ring.
Abnormal sound	Oversized valve, excessive pressure drop, air binding, or quick-operating valve nearby.	Resize valve, reduce pressure in two stages, install air vent, or relocate quick-operating valve.

Strainer Cleaning (For 25A - 50A)

Clean the built-in strainer at least once or twice a year.

1. Remove internal pressure by closing the inlet stop valve and opening the outlet stop valve.
2. Remove the strainer cap counterclockwise.
3. Wash the strainer in water and remove deposited scale.
4. Reinstall the strainer and cap, and check for leaks.

Structural Drawings and Parts List

25A - 50A Flanged

65A - 100A Flanged

Main Parts (25A-100A):

No.	Name of Parts	Material
1	Body	Bronze (CAC406)
2	Spring Chamber	Aluminium / Cast Iron
3	Valve Seat	Bronze (CAC406)
6	Spindle	Stainless Steel
8/13	Disc	FKM
17/19	Diaphragm	EPDM
23/22	Adjusting Screw	Stainless Steel
26/25	Spring	Alloy Steel