Yoshitake GD-27BP User manual

0EPDT-278
MODEL GD-27BP
Pressure Reducing Valve
with By-pass
PRODUCT MANUAL
Thank you very much for choosing the Yoshitake’s product. To ensure the correct and safe use of the product,
please read this manual before use. This manual shall be kept with care for future reference.
The symbols used in this manual have the following meanings.
Warning
This symbol indicates a potentially hazardous situation that, if not avoided, could
result in death or serious injury.
Caution
This symbol indicates a hazardous situation that, if not avoided, may result in
minor or moderate injury or may result in only property damage.
Table of Contents
1. Usage of the Product··················································1
2. Specifications
2.1 Specifications······················································1
2.2 Nominal size selection······································ 2 - 3
2.3 Flow rate characteristics chart·································3
2.4 Pressure characteristics chart ·································4
2.5 Noise characteristics chart ·····································4
3. Dimensions and weights··············································5
4. Structure··································································6
5. Operation·································································8
6. Installation
6.1 Piping example····················································8
6.2 Precaution for installation·······································8
7. Operation procedure
7.1 Precaution for operation·······································10
7.2 Adjusting procedure············································10
8. Maintenance
8.1 Troubleshooting·················································10
8.2 Precaution for maintenance and inspection··············11
8.3 Disassembly ·····················································12
8.4 Precaution for reassembly····································14
8.5 Tool for regulation and maintenance·······················15
9. Exploded view·························································16

1EPDT-278
1. Usage of the Product
In addition to pressure reducing function, the product has by-pass function and stop function and can be used
for a wide range of pressure control in a water supply system and others for the general households,
multistoried buildings, industrial plants, and plant facilities.
2. Specifications
2.1 Specifications
Model
GD-27BP
Nominal size
20-100A
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
Min. differential pressure
0.05 MPa
Max. pressure reduction
ratio
10:1
Max. temperature
90C
Material
Body
CAC406
Valve seat
CAC406
Valve disc
FKM
Diaphragm
EPDM
Connection
JIS 10K FF flanged
Installation posture
Horizontal or vertical installation is possible
(For 100A, horizontal piping with upward posture only.
See *1 below.)
The product conforms to the standard of the Japanese Water Supply Act.
The product does not use brass material for the wetted surface area.
Pressure gauge connection port is JIS R1/4.
Pressure reducing function is set when shipped from our factory.
*1 Installation posture of 100A
Caution
Please confirm that the indications on the product correspond with the specifications
of the ordered product model before use.
* If they are different, please contact us without using the product.
Vertical piping
Horizontal piping with
sideways posture
Horizontal piping
with upward posture

2EPDT-278
2.2 Nominal size selection
Rated flow table (The pressure difference before and after the product is 0.15 MPa or more)
Nominal size
20A
25A
32A
40A
50A
65A
80A
100A
Rated flow (L/min)
40
60
100
150
250
300
450
700
Nominal size selection chart
Nominal size 20A - 50A

3EPDT-278
Nominal size selection chart
Nominal size 65A -100A
2.3 Flow rate characteristics chart
Reduced pressure
range
Offset
A
0.05 - 0.35MPa
0.10MPa or
below
B
0.30 - 0.70MPa
0.15MPa or
below
Offset

4EPDT-278
2.4 Pressure characteristics chart
This chart shows variation in the reduced pressure when the inlet pressure of 0.6 MPa is changed
between 0.15 MPa and 1.0 MPa after the reduced pressure is set at 0.1 MPa.
2.5 Noise characteristics chart (Fluid: Water)

5EPDT-278
3. Dimensions and Weights
(mm)
Size
L
H1
H2
d
Weight
(kg)
20A
200
61
137
18
6
25A
200
61
137
18
7
32A
245
72
177
18
11
40A
245
72
177
28
12
50A
260
92
186
28
16
65A
328
99
257
45
30
80A
402
112
274
56
38
100A
470
134
328
72
58

6EPDT-278
4. Structure
Switching of three functions (pressure reducing function, by-pass function and stop function) is conducted
by operating stems at inlet side and outlet side and pointing the arrow at a certain point of the plate. See the
next page for the arrow position and fluid flow in each function.
Caution
1. Do not switch to stop function and by-pass function for purpose other than inspection or blow.
2. The insertion port of plug [42] is for installation of pressure gauge. Do not use this port for the
purpose of airtight or pressure capacity test.
* Failure to follow this notice may result in damage to the product.
3. When installing pressure gauge to the insertion port of plug [42], pressure is not applied to pressure
gauge at outlet side while in by-pass function due to structure of the product. To check pressure
while in by-pass function, see the value shown by pressure gauge at inlet side

7EPDT-278
■Pressure reducing function
■By-pass function
■Stop function

8EPDT-278
5. Operation
Spring [35] is compressed by adjusting screw
[32] and make diaphragm [16] pushed down, and
thereby open disc [12] directly connected to it.
Fluid coming in from the inlet side flows out
from the upper part of disc [12] to the outlet side,
and passes through the reduced pressure
detection hole, and is led to the bottom of
diaphragm [16].
Load of spring [35] and the reduced pressure
act to diaphragm [16], and the upper and lower
force keeps a balance and regulates the valve
opening. As a result, diaphragm [16] keeps
reduced pressure constant.
6. Installation
6.1 Piping example
6.2 Precaution for installation
Warning
1. Since the product is heavy, securely support it using lifting devices or the like when installing. See the
product weight specified in “4. Dimensions and Weights”on Page 5.
* Failure to follow this notice may cause a falling accident of the product, resulting in an injury.
2. Connect a blow-off pipe to the outlet side of safety relief valve, and lead it to a place where there is no
risk of physical damage even if fluid blows out.
* Failure to follow this notice may result in injury and scalds in the event that high temperature fluid
blows out.
Caution
1. Do not disassemble the product unless it is necessary.
* Failure to follow this notice may prevent the product from functioning properly.
2. Before installing the product in the piping, be sure to remove foreign substances and scale from the
piping.
* Failure to follow this notice may prevent the product from achieving its intended performance due to
the ingress of foreign substances and scale into the product.
3. Be sure to install a strainer at the inlet side of the product.
* Failure to follow this notice may prevent the product from achieving its intended performance due to
the ingress of foreign substances and scale into the product. It is recommended to use a strainer of 40
mesh or more.

9EPDT-278
4. Install a safety relief valve at the outlet side of the product for protection of equipment at outlet side.
* Failure to follow this notice may result in damage of the equipment.
5. Be sure to install pressure gauges at the inlet and outlet sides of the product.
* Failure to follow this notice hampers correct pressure adjustment.
6. If a quick operating valve such as a solenoid valve is installed, place it at a distance of at least 3
meters from the product.
* Failure to follow this notice may result in malfunction or a drastically shortened service life of the
product.
7. For two-stage pressure reduction, keep a distance of at least 3 meters between each product.
* Failure to follow this notice may prevent the product from functioning properly due to malfunction.
8. Install the product properly by checking the inlet, outlet and in proper posture.
* Installing the product in wrong directions prevents the product from functioning properly.
9. Install pipes so that excessive load, torque or vibration is not applied to the product.
10. On water pressure test for inlet side piping of the product, close stop valve at inlet side of the product or
switch the product function to stop function before the test. On water pressure test for outlet side
piping of the product, switch the product function to stop function before the test.
11. Install stop valve at inlet side of the product since stop valve is necessary for strainer cleaning or
pressure control at by-pass function.
12. The product can be installed either horizontally or vertically (For 100A, horizontal installation only).
13. Secure enough space for function switching operation. For disassembly and inspection, space more
than the space indicated by H3 andH4 below is needed.
(mm)
Nominal size
20A
25A
32A
40A
50A
65A
80A
100A
H3
160
160
170
170
190
200
210
230
H4
260
260
320
320
330
440
460
550

10 EPDT-278
7. Operation procedure
7.1 Precaution for operation
Caution
1. Before leading fluid into the product, switch the product function to by-pass function and remove
foreign substances and scale from the piping completely.
* Failure to follow this notice may prevent the product from functioning properly due to the ingress of
foreign substances and scale into the product.
2. To adjust the set pressure, turn the adjusting screw slowly.
* Failure to follow this notice may result in damage to the product and other equipment due to hunting
or other cause.
3. When the product is not used for an extended period, completely discharge fluid from the product and
pipes, and close the stop valve. If water remains in by-pass line, remove the plug and discharge water.
* Failure to follow this notice may cause malfunction of the product due to rusting inside the product
and the pipes.
7.2 Adjusting procedure
(See “4. Structure”on Page 6 and “9. Exploded view”on Page 16.)
Following a wrong adjusting procedure may cause hunting, scale problems or other problem, and can
heavily damage the main parts of the valve. To avoid these problems, be sure to follow the procedure
given below:
1. Close stop valve at inlet side of the product.
2. Turn stem to switch the product function to by-pass function.
3. Open stop valve at inlet side of the product and blow out fluid enough.
When reduced pressure exceed set pressure it is dangerous since safety relief valve at outlet side of
the product blows out. Regulate opening of stop valve at inlet side so that reduced pressure do not
exceed set pressure.
4. Close stop valve at inlet side of the product.
5. Turn stem and switch the product function to pressure reducing function.
6. Slowly open stop valve at inlet side of the product fully.
7. Remove domed cap nut [40], and turn adjusting screw [32] while watching the pressure gauge at the
outlet side.
Turn the adjusting screw to the right (clockwise) to increase reduced pressure.
Turn the adjusting screw to the left (counterclockwise) to decrease reduced pressure.
8. After the adjustment is complete, tighten domed cap nut [40].
Warning
When the product is used for hot fluid, do not touch the product with bare hands.
* The product having hot fluid may scald your skin.

11 EPDT-278
8. Maintenance
8.1 Troubleshooting
(See “4. Structure”on Page 6 and “9. Exploded view”on Page 16.)
Trouble
Cause
Remedy
Reduced pressure
rises and exceeds set
pressure.
1. There are foreign substances stuck
between disc [12] and valve seat
[3], or scratches on them.
1. Disassemble the product and remove
the foreign substances. If scratch is
observed on disc [12] or valve seat
[3], replace it.
2. O-ring [8] is damaged.
2. Replace O-ring [8].
3. Diaphragm [16] is damaged.
3. Replace diaphragm [16].
4. Packing at ball valve part is worn or
damaged.
5. By-pass function is set.
4. Please contact us.
5. Switch the functions.
Pressure does not
reach the desired
value.
1. Working pressure is improper.
1. Change to appropriate value. (See
“2.1 Specifications” on Page 1.)
2. Nominal size of the product is too
small for the flow rate for use.
2. Replace the product with the proper
nominal size. (See “2.2 Nominal size
selection” on Page 2.)
3. Pressure adjustment is improper.
3. Readjust the pressure in accordance
with the given procedure. (See “7.2
Adjusting procedure” on Page 10.)
4. Strainer at inlet side of the product
is clogged.
4. Clean the strainer.
5. Domed cap nut [40] is loosened.
6. Stop function is set.
5. Tighten domed cap nut [40].
6. Switch the functions.
Outside leakage
1. Bolt [38] is loosened.
1. Tighten bolt [38].
2. Plug [41] is loosened.
2. Replace plug [41].
3. Plug [42] is loosened.
3. Tighten plug [42].
Abnormal sound
1. Nominal size of the product is too
large for the specifications.
1. Replace the product with the proper
nominal size. (See “2.2 Nominal size
selection”on Page 2.)
2. Pressure reduction ratio is too
large.
2. Reduce pressure in two stages. (See
“2.1 Specifications” on Page 1.)
3. Air binding has occurred.
3. Install an air vent device.
4. Quick operating valve is located
near the product.
4. Keep a distance between them as
large as possible (3 m at least).
Most of problems with the pressure reducing valve are caused by foreign substances and scale in the
piping.Avoid the ingress of dust and dirt to the product with caution.
A phenomenon similar to valve failure could occur due to the failure of the pressure gauge, clogging of
the strainer, and other causes. Check the above possible causes and take a proper remedy and
preventive measures.

12 EPDT-278
8.2 Precaution for maintenance and inspection
(See “4. Structure”on Page 6 and “9. Exploded view”on Page 16.)
Warning
1. Completely discharge the pressure inside of the product, piping and equipment before disassembly and
inspection. Disassembly and inspection must be done by experienced professional or valve
manufacturer.
* Failure to follow this notice may result in scalds, injury or contamination on the surroundings due to the
residual pressure.
2. When disassembling the product at by-pass function or stop function is necessary, make sure not to
switch functions during disassembly.
* Failure to follow this notice may result in injury or contamination on the surroundings due to fluid
blowout.
3. If fluid is hot, do not touch the product directly with bare hands.
* Failure to follow this notice may result in scalds.
Caution
1. If problem occurs for a cause other than listed in "8.1 Troubleshooting" on Page 11, please contact us.
2. When the product is disassembled, internal fluid flows out. Receive it in a container.
* Failure to follow this notice may result in making the surroundings dirty.
3. Synthetic rubber is a consumable part. The replacement interval of the synthetic rubber part greatly
varies depending on the use conditions. The general guide for the replacement interval is shown below.
Service life
Part name
3 years
Diaphragm [16], O-ring [8], Disc [12]
5 years
O-rings (except for [8])
4. Ball valve part cannot be disassembled.
8.3 Disassembly
(See “9. Exploded view”on Page 16)
1. Remove domed cap nut [40] and turn adjusting screw [32] counterclockwise, and set spring [35] free
(no load).
2. Remove bolts [38] of spring chamber [2] and remove spring chamber [2]. Then take out spring [35]
and spring plate [31].
3. Remove nut [36], and then diaphragm shell [30] and diaphragm [16].
4. Remove set screw [15] (bolts [15] in the case of nominal size 65A to 100A) of valve seat [3], and
remove a set of the valve seat (valve seat [3], spindle [6], disc [12], and retainer [7], etc).
Nominal size 20A to 50A: Attach diaphragm shell [30] to spindle [6], and pull them up together.

13 EPDT-278
Nominal size 65Ato 100A: Screw bolt [15] into valve seat [3], and pull them up together.
5. Secure the part A of the spindle [6] (two faces), loosen the U-nut [14] with a tool, and remove disc
[12], and O-ring [11].

14 EPDT-278
8.4 Precaution for reassembly
(See “9. Exploded view”on Page 16)
Caution
1. Check to see that there is no foreign substances inside the body and on each part.
*Foreign substances prevent the product from functioning properly. To avoid the problem, remove
foreign substances.
2. Check that there is no scratch on disc or O-ring.
*A scratch on the relevant part prevents the product from functioning properly. Replace the damaged
part.
3. Apply silicone grease to the O-ring.
*Failure to follow this notice may damage O-ring.
Assemble the parts in reverse order of disassembly.
Tighten U-nut [14] and nut [36] by torque as below.
(N・m) (N・m)
Tighten bolts [38] of spring chamber [2] evenly in the diagonal order.
Nut [36]
Nominal
size
Tightening
torque
20-25A
8
32-50A
12
65-80A
18
100A
23
U-nut [14]
Nominal
size
Tightening
torque
20-25A
8
32-40A
12
50A
13
65-80A
18
100A
23

15 EPDT-278
8.5 Tool for regulation and maintenance
Part No.
Parts
Size of tool
Tool name
6
Spindle
20-25A:3 mm
Spanner or monkey wrench
32-50A:4 mm
65-80A:6 mm
100A: 7 mm
14
U-nut
20-25A:10 mm
32-40A:13 mm
50-80A: 17 mm
100A: 19 mm
26
Stem
20-25A: 9 mm
32-40A: 12 mm
50A: 14 mm
65-80A: 17 mm
100A: 19 mm
32
Adjusting screw
20-50A: 7 mm
65-100A: 11 mm
36
Nut
20-25A: 10 mm
32-50A: 13 mm
65-80A: 17 mm
100A: 19 mm
38
Bolt
20-25A: 10 mm
32-50A: 13 mm
65-100A: 17 mm
40
Domed cap nut
20-25A: 17 mm
32-50A: 19 mm
65-100A: 24 mm
42
Plug
20-100A: 9 mm
15
Set screw (15-50A)
Cross-head screwdriver
15
Bolt (65-100A)
65-100A: 13 mm
Socket wrench
41
Plug
20-100A: 6 mm
Hex key

16 EPDT-278
9. Exploded view
Note) Parts shown in the rectangle boxes are available as consumable supply and parts kit
Parts included are below.
Ball valve part cannot be disassembled.
Parts kit name
Parts included
Diaphragm
Diaphragm [16]
Disc
Disc [12]
O-ring set
O-ring([4],[5],[8],[9],[11] and [34])