Yoshitake DD-2 and DD-3 series compact direct-acting solenoid valves feature a stainless steel body and trim, offering superior corrosion resistance. Because they can be applied to various fluids, they are widely used for water supply and drainage systems in a house, plant facilities, and automatic controllers for industrial use.

Features

1. Outstanding corrosion resistance achieved by adopting stainless steel for major parts and body.
2. Significantly improved corrosion resistance with stainless steel made body and trim parts.
3. Various installation postures: Vertical or horizontal including intermediates.
4. Equipped with coil of AC 110/220V selective and common for 50 Hz/60 Hz.
5. DD-3-8N can be used as a pilot solenoid valve for constant water level valves up to 50A. (For 65A and larger, DP-200-N is recommended.)

Specifications

Model	DD-2	DD-2-8	DD-3	DD-3-8	DD-3-8N
Application	Steam, Air, Cold and hot water, N2 gas, CO2 gas (dry), Ar gas, Oil	Steam, Air, Cold and hot water, N2 gas, CO2 gas (dry), Ar gas, Oil	Air, Cold and hot water, N2 gas, CO2 gas (dry), Ar gas, Oil	Air, Cold and hot water, N2 gas, CO2 gas (dry), Ar gas, Oil	Air, Cold and hot water, N2 gas, CO2 gas (dry), Ar gas, Oil
Fluid viscosity	20 cSt or less	20 cSt or less	20 cSt or less	20 cSt or less	20 cSt or less
Working pressure	0-0.15 MPa	0-0.8 MPa	0-0.15 MPa	0-0.8 MPa	0-0.8 MPa
Orifice (mm)	φ9.5	φ4.0	φ9.5	φ4.0	φ4.0
Cv value	1.7	0.55	1.7	0.55	0.55
Allowable valve seat leakage	50 mL/min under standard conditions	50 mL/min under standard conditions	No leakage at the pressure gauge	No leakage at the pressure gauge	No leakage at the pressure gauge
Max. temperature	175°C	175°C	100°C	100°C	90°C
Operation	Normally closed	Normally closed	Normally closed	Normally closed	Normally closed
Body Material	Stainless steel (SCS14A)	Stainless steel (SCS14A)	Stainless steel (SCS14A)	Stainless steel (SCS14A)	Stainless steel (SCS14A)
Plunger Material	Stainless steel	Stainless steel	Stainless steel	Stainless steel	Stainless steel
Valve disc Material	PTFE	PTFE	FKM	FKM	FKM
Connection	JIS Rc screwed	JIS Rc screwed	JIS Rc screwed	JIS Rc screwed	JIS Rc screwed

Note

• DD-3-8N is an approved product by Japan Water Works Association (JWWA).
• Not available with pipe end core.
• When using the solenoid valve to pilot piping of a constant water level valve, select the direct type (DD-3-8N).

Specification of Coil

Rated voltage	AC 100 / 200 V selective type	AC 110 / 220 V selective type
Frequency	50 / 60 Hz common	50 / 60 Hz common
Allowable fluctuation	Rated voltage ±10%	Rated voltage ±10%
Rated current	0.42 / 0.21 A	0.38 / 0.19 A
Starting current	1.10 / 0.55 A	1.00 / 0.50 A
Insulation class	Insulation class H	Insulation class H
Protective structure	Dust tight, Splash proof	Dust tight, Splash proof
Ingress protection code	IP64 (JIS C0920)	IP64 (JIS C0920)
Insulation resistance	50 MΩ and more / 500 V megger	50 MΩ and more / 500 V megger
Withstand voltage test	1500V / min	1500V / min

Coil equipped with a terminal box (made of plastic) is also available.

Dimensions (mm) and Weights (kg)

Nominal size	d	L	H	H1	Weight (kg)
10A	Rc 3/8	50	85.5	12	0.66
15A	Rc 1/2	60	87.5	13	0.69
20A	Rc 3/4	65	91	16.5	0.74

Operation

(1) Opening operation When the coil is supplied with power, the plunger is pulled up and extends the spring upwardly, opening the valve.

(2) Closing operation When the coil is not supplied with power, the plunger drops down by its own empty weight and the spring load, closing the valve.

Nominal Size Selection Chart

For steam (Cv = 1)

For water (Cv = 1)

Model	φD(mm)
DD-2	9.5
DD-3	9.5
DD-2-8	4.0
DD-3-8	4.0

For air (Cv = 1)

Installation

Precaution for Installation

Warning

Electric wiring work must be performed by a professional.

1. When there is a risk of having life hazard, harming a body or property by the malfunction of the product, please install the safety device which operates interception, opening, warnings according to each facility. The product cannot be used as an emergency shutoff valve.
2. The product is not designed as a safety valve such as an emergency shutoff valve. If the product is applied to a system that needs safety measures, install other equipment besides the product to ensure the safety.
3. The product is not explosion-proof. Do not use it in the area or ambience where explosive gases accumulate. Doing so may cause fire.
4. Connect the cables only after confirming that no power is supplied. Failure to do so may cause an electric shock.
5. Connect the cables according to the instruction after confirming the rated voltage. Erroneous cable connection may cause an electric shock or fire.
6. Do not supply electric power to the coil while it is detached from the valve.

Caution

1. Vertical or horizontal installation is possible including the intermediates between vertical and horizontal positions, however, do not install it upside-down.
2. Before connecting piping to the product, remove foreign substances, dirt, etc. inside of the piping by flushing.
3. Match the fluid flow direction with the inlet and outlet of the product to ensure proper installation. (The valve will not close otherwise.)
4. Make sure to connect a strainer (80-100 mesh) to the inlet of the product.
5. Do not apply excessive load, torque or vibration to the product. Doing so may result in drastically shortened service life.
6. Secure the space required for disassembly or removal at maintenance or inspections.
7. Do not get the product wet. Failure to do so may result in an electric leakage.
8. Do not apply insulation to the solenoid coil. Doing so may cause an abnormal operation.
9. When the product is used in a facility which cannot stop operating, install a bypass line with a bypass stop valve. Use the bypass line while troubleshooting or disassembling the product so that the facility can keep operating.
10. Before piping, remove foreign substances and note that seal materials must not flow into the inside of the product and piping.
11. When using the product under the conditions where the outlet pressure can accidentally become higher than the inlet pressure, install a check valve at the outlet side to prevent backflow.
12. If the product is used in a steam line and negative pressure generates at its outlet side when it is closed, install a vacuum breaker at the outlet side.
13. When using the product in a steam line, install a steam trap in the line.
14. When the product is used in a steam line, install it in such a way that avoids condensate accumulation at the inlet side.
15. In case of a possible frozen line, take proper measures to remove water inside the piping or equip the product with insulating materials. Freezing may damage the product. Do not insulate the coil.

Piping Example

Wiring Method

1. Wiring differs according to voltage, AC 100 V or 200 V. Wire the coil according to the instruction on the label attached to the coil.
2. In order to prevent disconnection or insulation failure, avoid unnecessarily pulling the lead wires or subjecting them to excessive load while wiring or use.
3. Use electric wires which have a core of 0.75 mm² or more.
4. Use a fuse (3A) to protect the electric circuit. Use a circuit protector as follows if the product is used in a fuel supply system:
   • Rated voltage 100 V: 0.5 A circuit protector
   • Rated voltage 200 V: 0.3 A circuit protector
5. When using a terminal box, do not turn it to change its posture. Doing so may cause disconnection or insulation failure.

Operating Procedure

Test working

Before performing test working, be sure to close the stop valves installed at both the inlet and outlet sides of the product and remove foreign substances and scale completely by flushing the bypass line.

1. Before leading fluid into the product, switch it on and off a few times and confirm the sound caused by the plunger when the coil turns on.
2. Fully open the stop valve at the outlet side.
3. With the product at open condition, open the stop valve at the inlet side gradually and confirm the fluid flows to the end of piping.
4. Gradually close the stop valve at the outlet side, and confirm the fluid does not leak from connection parts of the product or piping.
5. With the product at closed condition, fully open the stop valves at both the inlet and outlet side.
6. Switch on and off the product a few times to confirm it operates correctly.
7. With the product at closed condition, confirm there is no leakage at the end of the piping.

Maintenance

Warning

Disassembling and inspections must be performed by a professional or a valve manufacturer.

1. Confirm that no power is supplied before disassembling or maintenance. Failure to do so may cause an electric shock.
2. Completely discharge the pressure inside of the product, line and equipment before disassembling or maintenance and cool down the product till it can be touched with bare hands in the case of high-temperature fluid.

Daily and periodic inspections

Conduct daily and periodic inspection/replacement in order to maintain the optimal performance of the product.

• Daily inspection (once every operational day): Check that the valve opens when switched on, and closes when switched off, using a pressure gauge. Inspect the product visually for external leakage.
• Periodic inspection (once every year): Disassemble the product and visually inspect the seal seat surfaces of the body. If damaged, replace the product. Inspect the seal seat surface and sliding surface of the plunger. If damaged, replace the plunger assembly.

Disassembly and reassembly

1. Loosen Hexagon nut (M14) and remove Tooth lock washer, Plain washer, Name plate and O-ring (Small), and then dismount Coil.
2. Remove Pipe with a spanner (32 mm width across flat).
3. Remove Plunger.
4. Reassemble the product in the reverse order of disassembling.
5. Tighten Pipe with the torque of 50 N·m, and Hexagon nut with that of 15 N·m.