Yoshitake GD-20RC is a primary pressure regulating and pressure sustaining valve designed for reliable response to pressure fluctuations. Coated with Nylon 11 on the internal and external surfaces, it offers excellent corrosion resistance. It features a large diaphragm and ensures no leakage when closed due to its single seat valve and valve disc design. The GD-20RC is widely used as a relief valve for pumps to relieve excess pressure caused by load fluctuations, and to sustain water pressure inside piping for mid-rise or high-rise building equipment when the pump is shutdown.

Features

• No leakage when closed due to single seat valve and valve disc.
• Large diaphragm ensures reliable response to pressure fluctuations and shutoff.
• Used as relief valves for pumps, relieves excess pressure caused by load fluctuations, and keeps internal pressure of piping constant during pump operation.
• Used to sustain water pressure inside piping when the pump of open circuit system for mid-rise or high-rise building equipment is shutdown.
• For the GD-20RC, the internal and external surfaces of the body are coated with Nylon 11, offering excellent corrosion resistance.

Specifications

Model	GD-20RC
Application (Fluid)	Hot and cold water
Inlet pressure (MPa) (15A-80A)	(A) 0.05-0.25 MPa (B) 0.26-0.7 MPa
Inlet pressure (MPa) (100A-150A)	(A) 0.05-0.25 MPa (B) 0.26-0.5 MPa
Installation posture	Vertical or horizontal installation (For 100-150A, horizontal installation with spring chamber vertically upward)
Fluid temperature	5 - 60 °C
Connection	JIS 10K FF Flanged

INFO

Body, spring chamber, cap and cover (65 - 150 A) are coated with nylon 11. Parts where nylon coating cannot be applied are treated with rust prevention measures such as painting.

Flow Rate Characteristics

Setting range (MPa)	Accumulation (MPa)
0.05 - 0.25	0.05
0.26 - 0.7	0.105

Operation

If the adjusting screw is turned right, the diaphragm will be depressed with the spring and valve disc connected with spindle will close.

Fluid passes along a conductor pipe and the sensing chamber under the diaphragm. If the pressure of the sensing chamber becomes higher than setting pressure, the load of the diaphragm bottom will overcome the load of the spring, will push up the valve, and will relieve excessive pressure.

If the pressure of the sensing chamber falls below setting pressure, the valve will be again closed by the load of the spring.

Installation and Piping Example

WARNING

• The product or parts will be damaged if an impact due to sudden pressure fluctuations such as water hammer is applied.
• If the product is in a closed pipe state, the fluid in the pipe will expand in volume due to the rise in fluid temperature, and the product will be damaged.
• Be sure to install a strainer at the inlet side of the product. Ingress of foreign substances or scale into the product leads to malfunction. It is recommended to use a strainer of 60 mesh or more.