Yoshitake GD-30 User manual

■PDT－136a■
Model ＧＤ－３０
PRESSURE REDUCING VALVE
Installation & Operation Manual
Please read this bulletin thoroughly before using the pressure reducing valve, so that you may do so
correctly and safely. Please carefully store this bulletin in a handy place.
―――――――――The following safety symbols are used in this manual. ――――――――
Warning
Caution
Contents
1. Features ················································································································· 1
2. Specifications ········································································································· 1
3. Dimensions and Weights····················································································· 1
4. Operation ··············································································································· 2
5. Nominal Size Selection Chart ············································································ 3
6. Installation
6.1 Example of piping ·························································································· 4
6.2 Precautions during installation ··································································· 4
7. Operating Procedure
7.1 Precautions during operation ······································································ 5
7.2 Adjustment procedures ················································································ 5
8. Maintenance Procedure
8.1 Troubleshooting ····························································································· 6
8.2 Precautions during maintenance and inspection ···································· 6
8.3 Disassembly ···································································································· 7
8.4 Exploded drawing ··························································································· 7
After Sale Service
This symbol indicates a potentially hazardous situation that, if not avoided,
could result in death or serious injury.
This symbol indicates a hazardous situation that, if not avoided, may result
in minor or moderate injury. (“Caution” may also be used to indicate other
unsafe practices or risks of property damage.)

1 ■PDT－136a■
1. Features
The compact, ultra-light GD-30 direct acting type pressure reducing valve features, Multi-function, ultra-light
and economical pressure reducing valve, consists of a stainless steel valve and valve seat, and a stainless
bellows sensor with pressure on the outside for high durability. The valve is well suited for a wide range of
applications, including kitchen systems, cleaning machines, disinfecting equipment, and food processing
equipment, etc.
2. Specifications
Application Steam
Connection NPT･BSPT or JIS Rc Screwed
Inlet Pressure 1.7MPa or less
Reduced Pressure
Type Spring Color Setting Pressure range
Ａ Spring Yellow 0.02～0.1ＭＰａ
Ｂ Spring Blue 0.05～0.4ＭＰａ
Ｃ Spring Yellow-green 0.35～1.0ＭＰａ
Minimum difference in Pressure 0.05ＭＰａ
Max. pressure reducing ratio 10：1
Max. Temperature 210℃
Valve Seat Leakage Rated leakage is 0.1% or less of rated flow
Caution
Please collate with attached nameplate and specification of ordered model.
※Please consult factory in case they do not match each other.
3. Dimensions and Weights
15A,20A,25A 40A,50A
(mm)
Size ｄ Ｌ Ｈ 1 Ｈ Weight (㎏)
15A
NPT 1/2, BSPT 1/2, Rc 1/2
80 47 191 1.9
20A
NPT 3/4, BSPT 3/4, Rc 3/4
85 47 191 1.9
25A
NPT １ , BSPT １ , Rc １
95 47 191 2.0
40A
NPT 1 1/2 , BSPT 1 1/2, Rc 1 1/2
140 77 307 10.1
50A
NPT 2 , BSPT 2 , Rc 2
150 77 307 10.4

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4. Operation
When the adjusting screw(⑪,⑫) connected to the handle (④,  ) pushes the spring(⑫,⑬)，the bellows(⑩,
⑨) are extended and the spindle(⑧,⑥) opens the valve(⑦,⑤).When the valve opens, the steam flowing to the
outlet side passes through the reduced pressure detection hole, and becomes an upwardly directed pressure under
the bellows and balances the force of the spring. The degree of valve opening is adjusted by the balancing of inlet
and reduced pressures, there by stabilizing reduced pressure.
15A,20A,25A 40A,50A
15A,20A,25A 40A,50A
No. Parts Name No. Parts Name No. Parts Name No. Parts Name
1 Body 9 Screen 1 Body 8 Screen
2 Spring chamber 10
Bellows 2 Spring chamber
9 Bellows
3 Cap 11
Adjusting Screw 3 Cap 12
Adjusting Screw
4 Handle 12
Spring 22
Handle 13 Spring
6 Valve Seat 13
Spring 4 Valve Seat 7 Spring
7 Valve 15
Bolts 5 Valve 19
Bolts
8 Spindle 6 Spindle

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5. Nominal Size Selection Chart
≪Example≫
Under the following operating conditions, the appropriate nominal size would be determined as described below.
･Inlet pressure(P 1 ): 1.3MPa
･Reduced pressure(P 2 ): 0.6MPa
･Steam flow rate:200kg/h
First, find the point where the inlet and reduced pressures intersect. Next draw a line straight down from that
point to the nominal size scale where a flow rate of 200kg/h or more is indicated. The appropriate nominal size is
indicated at the right side of the flow rate scale. For the above example, a nominal size of 20A should be
selected.

4 ■PDT－136a■
6. Installation
6.1 Example of piping
6.2 Precautions during installation
Warning
In case installing safety valve as safety device at outlet side, joint relief pipe at outlet of safety
valve and guide it to safety place where steam can relief out.
※Failure to do so may result in burns.
Caution
(1) Do not disassemble the valve unreasonably.
※ Disassembling the valve at your discretion may affect the original performance.
(2) Remove foreign matter and scales from the lines before connecting the valve.
※ Failure to do so may result in the valve from functioning incorrectly.
(3) Install a strainer (Recommendation: 60-mesh or close) at the valve inlet side.
※ Failure to do so may hamper correct pressure control, which affects the original performance.
(4) Install a safety valve at the valve outlet sides as safety device for equipment.
※ Failure to do so cannot identify PRV problem, resulting in equipment damage.
(5) Install a pressure gauge at both the inlet and outlet sides of the valve.
※ Failure to do so may hamper correct pressure adjustment.
(6) Install a steam trap to the inlet sides of the valve to prevent drainage problems.
※ Failure to do so may result in drainage problem, affecting the original performance.
(7) When installing quick open and close valves, such as a solenoid valve, install it at inlet side as
much as possible, and secure at least 3 m from the valve.
※ Failure to do so may result in malfunction or drastically shortened service life.
(8) When pressure reducing in two stages, secure at least 3 m between the valves.
※ Failure to do so may result in malfunction, affecting the original performance.
(9) Install the valve in proper direction of the fluid flow.
※ Failure to do so may affect the original performance.
(10) Do not apply excessive load, torque or vibration to the valve.
※ Doing so may result in malfunction or drastically shortened service life.
(11) Install the valve perpendicularly to horizontal lines.
(12) Provide the by-pass line. (See 6.1 Example of piping)
(13) Set pressure of safety relief valve should be higher than the pressure reducing valve’s pressure.
(14) When the reducing ratio is large, install a reducer to keep the flow velocity in the pipe 20 m/s to
30 m/s .

5 ■PDT－136a■
7. Operating Procedure
7.1 Precautions during operation
Warning
(1) Do not touch the valve directly with bare hands.
※Doing so may result in burns.
(2) Before flow the steam in pipe line, make sure steam can flow without any dangerous at the end of
pipe line and pipe line is connected tightly.
※In case steam blow off, it may result in burns.
Caution
(1) Close the stop valves before and after the reducing valve, and remove all foreign matter and
scales via the by-pass line before operation. And, open each stop valve slowly.
※ Failure to do so may prevent the valve from functioning correctly. And, It may cause hunting,
water hammer, etc., resulting in damage to the valve and other equipment when the stop valve is
opened quickly.
(2) When adjusting pressure, slowly turn the handle. Incorrect adjustment may cause hunting, water
hammer, etc., it may result in damage to the valve and other equipment.
(3) Remove fluid completely from the line, and close the stop valves before and after the valve when
not using it for long periods of times.
※Rust generated in the valves and lines may cause malfunction.
7.2 Adjustment Procedure
Lift up the handle to unlock. Then turn the handle in the direction of the (＋) symbol on the name plate
raises reduced pressure. Turning in the direction of the (－) symbol reduces pressure. The handle goes back
to original position when your hand is released.
Caution
Use working gloves because there is a possibility that the handle get heated.
※Doing so may result burns.

6 ■PDT－136a■
※There is a possibility that the handle is
stuck and cannot be removed. It is easier
to turn the handle to obtain high reduced
pressure if a screwdriver(axis diameterφ6)
is used as follows.(For the nominal sizes of
40A and 50A)
(1) Lift up the handle to unlock.。
(2) Insert a screwdriver in the handle through
notches, and turn it to the left or right.
8. Maintenance Procedure
8.1 Troubleshooting
Problem Cause Solution
Pressure does not
rise to the desired
level.
1.Incorrect pressure is being used. 1.Correct the pressure.
2.Nominal size is too small for these
specifications.
2.Replace with the correct nominal sized
item.
3.Incorrect adjustment. 3.Re-adjust according to the adjustment
procedure.
4.Screen is clogged. 4.Disassemble and clean.
5.Pressure gauge malfunction. 5.Replace the pressure gauge.
Reduced pressure
exceeds prescribed
level.
1.Foreign matter is embedded in
the valve and/or
valve seat, or else scratches exist.
1.Disassemble and clean. If scratches
exist, polish them away.
2.Reduced pressure sensing hole is clogged with
foreign matter.
2.Disassemble and clean.
3.By-pass valve is leaking. 3.Repair or replace the valve.
Abnormal noise is
heard.
1.Pressure reduction ratio is too large. 1.Use a two-stage reduction.
2.Drainage problem. 2.Install a trap.
3.An abrupt open/close valve is located too close
to the pressure reducing valve.
3.Move distance as much as possible
between the valves.
8.2 Precautions during maintenance and inspection
Warning
Completely discharge internal pressure from the valves, lines, and equipment, and cool the valve down to
a level where you can touch it with bare hands before disassembly and inspection.
※Failure to do so may result in injury or burns due to residual pressure or spillage around the valve.
Caution
(1)In order to maintain original performance and function, examine daily and personal inspection. And,
periodical inspection must be examined according to the regulations of every kind.
※ For general users, request to specialized in dealer or manufacture.
(2)Pressure reducing valve shall be disassembled and inspected by qualified person or manufacture.
※ Request the treatment to specialized dealer or manufacture in case of any problems.
(3)While disassembly, drain flow out from the valve, so catch it by container. And release steam completely
before disassembling.
※In case of no container for drain, it makes dirty surrounding the valve.
(4)Close the stop valves before and after the reducing valve, and remove all foreign matter and scales via
the by-pass line before operation.
※ Failure to do so may result in the valve from functioning incorrectly.

7 ■PDT－136a■
8.3 Disassembly Procedure (Refer to 4.Operation)
(1) Discharge the valve's internal pressure until a zero pressure condition is established.
(2) While lifting the handle, turn it in the Counter-Clock Wise direction(minus direction of nameplate at top of
handle) until the spring is free(no-load).
(3) Unscrew the bolt which secures the Spring Chamber and remove the Spring Chamber(handle etc. cannot be
disassembled),the spring ,the bellows, and the spindle.
(4) Remove the cap by turning it in the CCW direction then extract the spring, Screen, and valve from the body.
(5) Assemble in the reverse order of Disassembly. And tighten the bolts evenly. Assemble the valve due to the
order. Failure to do so may lead to not assemble correctly. And if the hexagon bolts are not screwed correctly,
it may cause steam leakage problem.
8.4 Exploded drawing
15A,20A,25A
※Part names shown in boxes are consumable items.

8 ■PDT－136a■
40A,50A
※Part names shown in boxes are consumable items.

2015.8
PDD-046e
Warranty Information
1. Limited warranty
This product has been manufactured using highly-advanced techniques and subjected to
strict quality control. Please be sure to use the product in accordance with instructions on
the manual and the label attached to it.
Yoshitake warrants the product to be free from any defects in material and workmanship
under normal usage for a period of one year from the date of receipt by the original user, but
no longer than 24 months from the date of shipment from Yoshitake’s factory.
2. Parts supply after product discontinuation
This product may be subject to discontinuation or change for improvement without any prior
notice. After the discontinuation of the product, Yoshitake supplies the repair parts for 5
years otherwise individually agreed.
3. This warranty does not cover the damage due to any of below:
(1) Valve seat leakage or malfunction caused by foreign substances inside piping.
(2) Improper handling or misuse.
(3) Improper supply conditions such as abnormal water pressure/quality.
(4) Water scale or freezing.
(5) Trouble with power/air supply.
(6) Any alteration made by other than Yoshitake.
(7) Use under severe conditions deviating from the design specifications
( e.g. in case of corrosion due to outdoor use).
(8) Fire, flood, earthquake, thunder and other natural disasters.
(9) Consumable parts such as O-ring, gasket, diaphragm and etc.
Yoshitake is not liable for any damage or loss caused by malfunction or defect of the product.
INTERNATIONAL DEPT.
955-5, Miyamae, Irukadeshinden, Komaki, Aichi, 485-0084, Japan
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