WO81

Manostar gauge
List ofproducts

WO81

WO81
Utility model registration No. 823971

High-accuracy fine differential pressure gauge

RoHS• Boasting a wide variety, the product is also compatible with airflow
WO71

rate and speed scales (refer to page 15).
• Easy-to-read wide angle scale (pointer rotation angle of 270°)• Pipe connection port that facilitates polarity conversion

FR51A• Unique mechanism less subject to abnormal high pressure inrush• High-performance silicone rubber diaphragm with small hysteresis

MS99• Band-link mechanism that prevents the pointer from vibrating

MS99S

MS61A-RA

QDP33

EMD8A

EMD7

Model WO81F

Model WO81PC(surface type)

Model WO81PR(round panel type)(square panel type)

EMT1

EMTGP1

Example of
selectionof memory
pointer

EMT1H

EMT6

*Memory pointer canbe set at an arbitrary
position.
With single memory pointer

EMP5A

With double memory pointers

EMRT1

Product code

WO81

HWS15A

Accessories
Application

Precautions
Maintenance<Main application fields>• Nuclear facilities• Food-related factory management
equipment• Air-conditioning control equipment
in high-rise building• Hospital and medical facilities• Automotive manufacturing/semiconductor manufacturing lines• Control of air discharge pressure
from coffee roaster<Usage>• Room pressure measurement in aclean room
• Detection of clogging of air filter• Measurement of airflow rate/speedof ventilation/exhaust device andothers*(Refer to pages 114 to 117)

11

Pressure range code

Ｆ

Ｎ

50

Ｄ Ｖ

(Example)
Mountingorientation

Unit
Range
Memorypointer

External
shape◆When making an inquiry or placing an order, specify the above product code.
◆For airflow rate/speed meter, refer to page 15.

Ｖ
Ｈ

Range for specification of verticalmounting
Range for specification of horizontal
mounting

None

Range for arbitrary mounting

Ｄ
Ｅ

Pa
kPa

Maximum scale value(for ± range, provide “±” as well)ＮＳ
Ｔ

No memory pointer

Ｆ
PC
PR

Surface type

Single memory pointer
Double memory pointers

Round panel typeSquare panel type

WO81

Manostar gauge
WO81

List ofproducts

Specifications
Main bodySurface type

Round panel typeSquare panel type

Ｆ

PC

PR

Ｎ

WO81FN

WO81PCN

WO81PRNＳ

WO81FS

WO81PCS

WO81PRSＴ

WO81FT

WO81PCT

WO81PRT

Memory pointerModel

No memory pointerSingle memory pointer(red)

Pressure unit
Pressuremeasurement
methodPressure-receiving
element
Measured gas
Scale indication
angle
Operating ambient
temperature
Operating ambient
humidity
Instrument bodywithstanding
pressure
Exterior material
Durable impact
Durable vibration

Accessories
Pressure range
code
50 DH
50 DV
100 DH
100 DV

Double memory pointers (oneeach for red and green)

Diaphragm
Air and noncorrosive gas (liquid cannot be measured)Wide-angle indication of approx. 270 degrees−10℃ to +50℃ (no freezing allowed)

200 kPa (refer to page 118)
Polycarbonate and polyamide
100 m/s2 (six times each for three axial directions)
5 to 10 Hz Amplitude of 10 mm,
10 to 50 Hz Acceleration of 39 m/s2 (two hours each forthree axial directions)

WO81PR

Mounting screw set

Mounting nut set (already mounted on gauge body)

0–50 Pa
0–100 Pa

0–300 Pa

500 D

0–500 Pa

1000 D

0–1000 Pa

1E

0–1 kPa2E

0–2 kPa3E

0–3 kPa5E

0–5 kPa

10 E

0–10 kPa

20 E

0–20 kPa

30 E

0–30 kPa

50 E

0–50 kPa

100 E

0–100 kPa

50 DV

−50 to +50＋－ 100 D−100 to +100 Pa＋－ 200 D−200 to +200 Pa＋－ 300 D−300 to +300 Pa＋－ 500 D−500 to +500 Pa＋－1000 D−1000 to +1000 Pa＋－

1E−1 to +1 kPa＋－

2E−2 to +2 kPa＋－

3E−3 to +3 kPa

Mounting orientation(Refer to page 18)
Horizontal (specification)
Upright (specification)

Accuracy (Note)(at 20℃ )Pressure-receiving
element material

Withstanding pressure ofpressure-receiving element

MS99

MS99S

MS61A-RA

EMD7(Refer to page 118)

±5％ FS

EMT1

Horizontal (specification)
Upright (specification)

FR51A

EMD8A

WO81PC

Pressure range

WO71

QDP33

Approx. 270 g

Mass

Two sets of mounting fittings (already mounted ongauge body)

300 D

50 DH

• Vinyl pipe or rubber pipe (inner diameter of 6 mm)……Base for resin vinyl pipe (already mounted ongauge)• Metallic pipe (outer diameter of 6 ± 0.1 mm)……Separately sold base for metallic pipe isnecessary.
• Hard plastic pipe (outer diameter 6 mm × inner diameter
4 mm)……Separately sold base for metallic pipe and inner
sleeve set (refer to page 111) or push-in joint isnecessary.
• Identification with red on high pressure side and blue on
low pressure side• By exchanging the base on the high-pressure side withthat on the low pressure side, it is possible to change
the polarity.

WO81F

0–200 Pa＋－

Base polarity

90% RH or below (no condensation allowed)

200 D

＋－

Compatible pipePa, kPa
Differential pressure method

WO81

10 kPa
±2.5％ FSEMTGP1EMT1H
40 kPaEMT6

Between horizontal andupright
Arbitrary mounting±1.5％ FS

EMP5A
Silicone rubber

EMRT1
150 kPa

HWS15A
Horizontal (specification)
Upright (specification)±2.5％ FS

10 kPaAccessories
Application

Precautions

Between horizontal andupright
Arbitrary mounting±1.5％ FS

40 kPaMaintenance(Note) Accuracy in full span (refer to page 121)
◆For biased pressure range, the polarity symbol “-” can be indicated for a fee. If the indication is necessary, make a request at the time oforder placement.
◆For use environment, refer to page 118.

12

WO81

Manostar gauge
List ofproducts

WO81

WO71

WO81

List of scales

Biased pressure range◆The polarity symbol “-” can be indicated for a fee. If the indication is necessary, makea request at the time of order placement.

FR51A

MS99

Pressure range Minimum scale
0–2 kPa
0.02 kPa
0–20 kPa
0.2 kPa

MS99S

MS61A-RA

QDP33

Actual size
EMD8A

EMD7

Pressure range Minimum scale
0–50 Pa
0.5 PaPressure range Minimum scale
0–3 kPa
0.02 kPa
0–30 kPa
0.2 kPaEMT1

EMTGP1

EMT1H

EMT6

EMP5A

EMRT1

Pressure range Minimum scale
0–100 Pa
1 Pa
0–1000 Pa
10 Pa
0–1 kPa
0.01 kPa

Pressure range Minimum scale
0–300 Pa
2 Pa

Pressure range Minimum scale
0–5 kPa
0.05 kPa
0–50 kPa
0.5 kPa

Pressure range Minimum scale
0–200 Pa
2 Pa

Pressure range Minimum scale
0–500 Pa
5 Pa

Pressure range Minimum scale
0–10 kPa
0.1 kPa
0–100 kPa
1 kPa

HWS15A

Accessories
Application

Precautions
Maintenance

13

WO81

Manostar gauge
WO81

List of scales

List ofproducts

Zero center range

WO81

WO71

FR51A

MS99

MS99S

MS61A-RA

QDP33

Actual size

EMD8A
Pressure range Minimum scale−50 to +50 Pa
1 Pa

EMD7

EMT1

EMTGP1

EMT1H

EMT6

EMP5A
Pressure range Minimum scale−100 to +100 Pa
2 Pa−1000 to +1000 Pa
20 Pa
0.02 kPa−1 to +1 kPa

Pressure range Minimum scale−300 to +300 Pa
5 Pa

Pressure range Minimum scale
0.05 kPa−2 to +2 kPa

EMRT1

HWS15A

Accessories
Application

Precautions
Maintenance

Pressure range Minimum scale−200 to +200 Pa
5 Pa

Pressure range Minimum scale−500 to +500 Pa
10 Pa

Pressure range Minimum scale−3 to +3 kPa
0.05 kPa

14

WO81

Manostar gauge
List ofproducts

WO81

Model WO81F
External dimension drawing
Installation of base on side face…………(standard condition at time of shipment from factory)

WO71

VT base (for vinyl pipe)
φ101

φ128

îĳPRXQWLQJKROH
îGLYLVLRQ

FR51A

φ114
0HPRU\SRLQWHU

MS99
0HPRU\SRLQWHU=HURSRLQWVHWWLQJGHYLFH

6HDOLQJFDS:LGWKDFURVVIODWVMS99S

MS61A-RA

3RLQWHU

QDP33

EMD8A

*UHHQPHPRU\SRLQWHUVHWWLQJGHYLFH

79

5HGPHPRU\SRLQWHUVHWWLQJGHYLFHîĳ KROH

EMD7RUî0WDSîGLYLVLRQ

φ7

69

EMT1

27

EMTGP1φ114±0.3

138

EMT1H

3DQHOFXWWLQJ

EMT6

EMP5A

EMRT1

Example of base arrangement
Installation of base on side face
MT base (for metallic pipe)

HWS15AVR base (rotary type for vinyl pipe)
φ7:LGWKDFURVVIODWV:LGWKDFURVVIODWVPrecautions（143）

φ6±0.1

Application&RPSDWLEOH
SLSHGLDPHWHU

Accessories:LGWKDFURVVIODWV121
134

Maintenance！
Caution17

Base tightening torque: 1 N·m Sealing cap tightening torque: 0.5 N·m
Do not tighten to a torque that exceeds the specified value because doing sobreaks the gauge body. (Refer to page 120.)

WO81

Manostar gauge
Model WO81F

List ofproducts

Installation of base on rear face
VT base (for vinyl pipe)

WO81

MT base (for metallic pipe):LGWKDFURVVIODWV:LGWKDFURVVIODWVîĳ KROH
RUî0WDSîGLYLVLRQîĳ KROH

WO71

φ6±0.1（30）

15&RPSDWLEOH
SLSHGLDPHWHU

FR51A

79

φ114±0.3

MS99

3DQHOFXWWLQJ$GDSWHUIRUUHDUIDFHSLSLQJ

MS99S

VR base (rotary type for vinyl pipe)$GDSWHUIRUUHDUIDFHSLSLQJ

19îĳ KROH
RUî0WDSîGLYLVLRQＲ9VORWWHGKROH

MS61A-RA

QDP33
79:LGWKDFURVVIODWVφ114±0.3

EMD8A

3DQHOFXWWLQJ

26

EMD7

Change of base arrangement

Possible base arrangement

Impossible base arrangement

The WO81F type has two base mounting
holes on each of the side face and the rear
face, allowing various base combinations
depending on the piping conditions.

！
CautionEMTGP1

Be sure to use bases in the1．
combination of one high-pressure
side (red) base and one lowpressure side (blue) base.
2. There are impossible basearrangements as shown on theright.
 t two mounting holes on the
3. A
gauge body that are not installedwith bases, be sure to attach thesealing caps.

EMT1H
6HDOLQJFDS%DVH

6HDOLQJ
FDS

%DVH

EMT6
6HDOLQJFDS

6HDOLQJ
FDS

%DVH

%DVH

Mounting orientation and range
Range for mounting orientation arbitrary mounting between horizontal and upright0 to 50Pa，0 to 100Pa，-50 to +50Pa

Whole range other than on the left

It is necessary to specify the mounting orientation (horizontal, upright, and others) at the timeof order placement.
*It is not possible to manufacture such a gauge whose mounting orientation exceeds 135°
for the range of 0 to 50 Pa.

The gauge can be mounted at an arbitrary angle between horizontal and upright.
For other mounting orientations, it is necessary to specify the orientation at the timeof order placement.

8SULJKW

0RXQWHGDWD
UELWUD
U\D
QJO
HE
90°
HW

8SULJKWSODQH
10° 10°

2WK
HUV

45
°

HWS15A

Accessories
Application

GXSULJKW
WDODQ
L]RQ
KRU
HQ
ZH

180°

5°

+RUL]RQWDO
SODQH

13

+RUL]RQWDO

0°

20°

2WK
HU
V

8SULJKWSODQH
10°

2W
KH
UV

5°

13

180°

EMP5A

EMRT1

Range for the specification of horizontal and upright mounting

90°

EMT1

0°

Precautions
Maintenance+RUL]RQWDO
SODQH
20°

20°

18

WO81

Manostar gauge
List ofproducts

WO81

Model WO81PC
External dimension drawing

Example of base arrangement
MT base (for metallic pipe)

VT base (for vinyl pipe)

（74）

WO71
φ100

17

72
:LGWKDFURVVIODWV:LGWKDFURVVIODWV

FR51A

φ6±0.1&RPSDWLEOH
SLSHGLDPHWHU

VR base (rotary type for vinyl pipe)

φ7

MS99S

77

φ95

MS99

MS61A-RA

70
63

QDP33

:LGWKDFURVVIODWV
7ZRVHWVRIPRXQWLQJILWWLQJVEMD8A:LGWKDFURVVIODWVĳ KROH

EMD7

EMT1

φ7

EMTGP1

3DQHOFXWWLQJ

EMT1H

EMT6

EMP5A

Mounting method

EMRT1'ULYHU

HWS15A

Accessories

6FUHZ$6FUHZ$0RXQWLQJVFUHZ%Application

Precautions
Maintenance

0RXQWLQJILWWLQJV

1. Loosen screw A, and remove bothmounting fittings from the gauge
body.

3DQHO

0RXQWLQJILWWLQJV

2. Fit the gauge to the front of the panel
first, put two mounting fittings back,and tighten screw A to secure thegauge.

！
Caution

19

3DQHO

3. Alternately tighten little by little
mounting screws B in two places tosecure the gauge to the panel.

Mounting screw B tightening torque: 0.5 to 0.6 N·m
Do not tighten to a torque that exceeds the specified value because
doing so breaks the gauge body.

WO81

Manostar gauge
Model WO81PR

List ofproducts

External dimension drawing

WO81

MT base (for metallic pipe)

VT base (for vinyl pipe)

（70）

21

100

WO71

68
:LGWKDFURVVIODWV

FR51A

φ7
î0PRXQWLQJ
VFUHZ

φ6±0.1&RPSDWLEOH
SLSHGLDPHWHU

77

φ95

100

:LGWKDFURVVIODWVVR base (rotary type for vinyl pipe)
66
59

MS99S

MS61A-RA

QDP33:LGWKDFURVVIODWV

80±0.3MS99:LGWKDFURVVIODWVîĳ KROH

EMD8A

80

80±0.3

EMD7
φ7

EMT1

ĳ KROHEMTGP1

3DQHOFXWWLQJ
80

EMT1H

EMT6

Mounting method

EMP5A
1. From four corners of the squaregauge mounting frame, remove
the M4 nuts, spring washers, andflat washers.
(Be sure to install the gauge without removing the spacer nuts asshown in the figure.)0QXW

6SDFHUQXW

6SULQJZDVKHU)ODWZDVKHU

2.	After installing the gauge in thepanel, tighten the flat washers,
spring washers, and M4 nuts inthat order from the rear side.

！
Caution！
Caution

EMRT1

HWS15A

0D[LPXPWKLFNQHVVRIPRXQWLQJSDQHOPP• If you install the gauge to the panel after removing the spacer nut, the gauge frame
may break.
• M4 nut tightening torque: 1 N·m
Do not tighten to a torque that exceeds the specified value because doing so breaks
the gauge body.

Accessories
Application

Precautions
MaintenanceBase tightening torque: 1 N·m
Do not tighten to a torque that exceeds the specified value because doing sobreaks the gauge body. (Refer to page 120)

20

WO81

Manostar gauge
List ofproducts

WO81

WO81
Overview of structure
9

8

WO71

6

10

7

5

Number

13

FR51A
14

MS99
3

2

MS99S

MS61A-RA

11

QDP33
4

Diaphragm2

Low-pressure side base (blue)

3High-pressure side base (red)4

Sealing cap

5

Scale plate

6

Zero point setting device

7

Memory pointer setting device

8

Pointer

9

Memory pointer10

Transparent cover

11

Housing

12

Base

13

Cover packing

14

Cover retention ring

12

4

1

Name

1

EMD8A

EMD7

Accessories dedicated to WO81

RoHS

Sealing cap
EMT1

EMTGP1

Dedicated
to F typeThis is already installed when the gauge is purchased.
Item number

EMT1H

Portable box(Auxiliary
item)

Dedicated to
F type

KGA81PLG

Material

Polypropylene

Mounting fitting set
EMT6(Auxiliary
item)

Dedicated to PC
type

EMP5A

EMRT1

HWS15A

Accessories
Application

The combination of parts in the photograph constitutes one set.
On the gauge, two sets (for one gauge) are already installed as astandard accessory.

Item number

Material

Item number

Material

TKA81PC

Aluminum die casting/steel

PB-01

Steel

Accessories for WO81

RoHS

VT baseHigh-pressure
side(Auxiliary
item)*Gauge body is not included.

VR baseLow-pressure side

(Auxiliary
item)

Low-pressure side

High-pressure side

Precautions
MaintenanceItem number

KGA81VT-H-P

Material

Polypropylene

Item number

KGA81VT-L-P

Material

Polypropylene

A vinyl pipe or rubber pipe with an inner diameter of 6 mm can be connected.
This is already installed when the gauge is purchased.

21

Item number

KGA81VR-H

Material

Brass

Item number

KGA81VR-L

Material

Brass

This serves as an elbow whose tube mounting part rotates. A vinyl pipe orrubber pipe with an inner diameter of 6 mm can be connected.

WO81

Manostar gauge
WO81

List ofproducts

Accessories for WO81

RoHS

PT baseLow-pressure side

High-pressure side

WO81

PR baseLow-pressure side

High-pressure side

WO71

FR51A

Item number

Material

MS99

The tube mounting part is a push-in joint. For piping, use theseparately sold tube (refer to page 112) or a tube compatible with JIS
B 8381-1.
(Connectable tube outer diameter: 6 mm)

The tube mounting part is a rotary elbow push-in joint. The
piping is the same as that for the PT base. (Connectable tube
outer diameter: 6 mm)

MS99S

MT baseMR baseKGA81PT-H

Material

PBT/brass

Item number

KGA81PT-L

Material

PBT/brass

Low-pressure side

High-pressure side

Item number

Material

KGA81PR-H

PBT/brass

Item number

KGA81PR-L

PBT/brass

MS61A-RA

Low-pressure side

High-pressure side

QDP33

EMD8A
Item number

Material

KGA81MT-H

Brass

Item number

Material

KGA81MT-L

Brass

Item number

Material

KGA81MR-H

Brass

Item number

Material

KGA81MR-L

Brass

A metallic pipe, such as copper pipe and aluminum pipe, with an outer
diameter of 6 ± 0.1 mm can be connected. However, for stainless steel
pipe, use an MTW base. When connecting with a plastic pipe (outer
diameter 6 mm × inner diameter 4 mm), remove the brass sleeve and use
the separately sold resin inner sleeve set (XIN6×4; refer to page 111).

This serves as an elbow whose tube mounting part rotates.
The piping material is the same as that for the MT base. Whenconnecting with a plastic pipe (outer diameter 6 mm × innerdiameter 4 mm), remove the brass sleeve and use the separately
sold resin inner sleeve set (XIN6×4; refer to page 111).

MTW base

Adapter for rear face piping

Low-pressure side

High-pressure side

Highpressure
side(Dedicated to F typerear face piping)

Lowpressure
side(Dedicated to F typerear face piping)

EMD7

EMT1

EMTGP1

EMT1H

EMT6

EMP5A
Item number

KGA81MTＷ-H-S

Material

Stainless steel

Item number

KGA81MTＷ-L-S

Material

Stainless steel

This is used to connect a stainless steel pipe with an outer
diameter of 6 ± 0.1 mm.

Item number

KGA81FBA-H

Brass

Item number

Material

KGA81FBA-L

BrassWhen arranging an MT base on the rear face of the WO81F type, thisadapter is required as a spacer for hooking a stabilizing wrench to thebase at the time of pipe connection. This adapter is also required whenarranging the VR base or MR base (excluding MTW base) on the rearface in order to avoid interference between the base and panel. Whenconnecting an R1/8 joint, use an R1/8 base adapter.

R1/8 base adapter

Low-pressure side

High-pressure side

EMRT1

HWS15A

Accessories

R1/8 base adapter (SUS)

Low-pressure side

High-pressure side

Material

Application

Precautions
MaintenanceItem number

KGA81R1/8AD-H

Material

Brass

Item number

KGA81R1/8AD-L

Material

Brass

It is possible to connect an R1/8 joint.
*The specifications of this adapter differ from those of theadapter for rear face piping.

Item number

KGA81R1/8AD-H-S

Material

Stainless steel

Item number

KGA81R1/8AD-L-S

Material

Stainless steel

It is possible to connect an R1/8 joint.
*The specifications of this adapter differ from those of theadapter for rear face piping.

22

Warranty■Warranty period
The warranty period for our product is one (1) year from delivery to the location specified by the orderer who makes a direct transaction
with us.

■Scope of warranty
If any failure or defect attributable to us becomes clear during the above warranty period, we will repair the product or supply asubstitute product free of charge. However, even during the warranty period, we will exclude the product from the scope of the warranty
if the failure or defect corresponds to any of the following:(1) The failure or defect was caused by an unreasonable condition, environment, handling, or usage not mentioned in the
instruction manual, specifications, and our product catalog.
(2) The failure or defect was caused by a factor other than our product.
(3) The failure or defect was caused by a modification or repair conducted by a party other than us.
(4) The failure or defect was caused by an event that could not be foreseen at the scientific and technical levels at the time of
product shipment from us.
(5) The failure or defect was caused by an external factor not attributable to us, such as acts of God and disasters.
Please note that the warranty mentioned here means the warranty for our individual product, and damage provoked by a failure or
defect of the product is excluded from the scope of the warranty.
*This warranty is valid only in Japan.

Application and usage
Our products are designed and manufactured as general-purpose instruments for general industries.
Therefore, our products are not intended for the following uses, and our products used in such a manner are outside the scope of
application.
(1) Equipment that is anticipated to greatly affect lives and properties, such as nuclear power generation, aviation, railways, marine
vessels, vehicles, and medical devices(2) Utilities that include electricity, gas, and service water(3) Use in outdoor locations and under similar conditions or environments other than those stipulated in the instruction manual(4) Usage to which considerable safety consideration and attention equivalent to (1) and (2) above need to be given

Service■Scope of service
Because the product price does not include service expenses, such as the dispatch of engineers, we will separately charge for the
expenses in the following cases:(1) Instruction for installation and adjustment and a witnessed test run(2) Maintenance inspection, adjustments, and repairs(3) Technical guidance and technical education(4) Witnessed inspections of products at our factory<<Note>> The product specifications and information in this catalog are subject to change without prior notice for product improvement orother reasons.

●For order placement, contact

Generalagent

Manostar Shop Co., Ltd.

1-2-3 Nishishiriike-cho, Nagata-ku, Kobe City, Hyogo 653-0031
TEL. +81-78-621-7000 FAX. +81-78-621-7788

Manufacturer

Yamamoto Electric Works Co., Ltd.

1-2-3 Nishishiriike-cho, Nagata-ku, Kobe City, Hyogo 653-0031
TEL. +81-78-631-6000 FAX. +81-78-631-6020

SEPTEMBER 2021 YAMAMOTO ELECTRIC WORKS CO., LTD., JAPAN