mycom UD Series User manual

2200X2JE-MY-S2-N_2020.09.
UD-series Screw Compressor
Instruction Manual
CAUTION
Read this manual carefully and thoroughly before operating, maintaining or inspecting this
product. It is important to fully comprehend the contents of this manual. Keep the operation
manual in a safe, designated place for future reference whenever the need arises.
Specifications of this product are subject to change without prior notice.
125SUD/125LUD
160SUD/160MUD/160LUD
200SUD/200MUD/200LUD
250SUD/250MUD/250LUD
320SUD/320MUD/320LUD/320LLUD
400SUD/400MUD/400LUD/400LLUD/
400XLUD

Preface
UD-series Screw Compressors
i
Preface
Thank you for purchasing the UD-series/screw compressor (hereinafter referred to as
"this product").
This instruction manual (hereinafter referred to as "this manual") describes safety information,
operational and detailed maintenance procedures for safe and effective use of this product、It is
applicable to the following compressor types
125SUD, 125LUD, 160SUD, 160MUD, 160LUD, 200SUD, 200MUD, 200LUD, 250SUD, 250MUD,
250LUD, 320SUD, 320MUD, 320LUD, 400SUD, 400MUD, 400LUD, 400LLUD, 400XLUD
Before installing or using this product, make sure you read this manual.
Keep this manual in a safe place near this product for quick reference whenever needed.
Revision History
Title of Instruction Manual Document No. Date of Initial Issue
UD series Instruction Manual 2200X2JE-MY-S2-N_2020.09. September, 2020
Rev. No.
Issue Date Revision Details Prepared/Approved by
00 Sep. 03, 2020 Completely revised by re-issuing as electronic version
and Document number change Takita/ Muta

Warranty and Disclaimer
UD-series Screw Compressors
ii
Warranty and Disclaimer
Warranty Clauses
If malfunctions or damages occur under proper usage and conditions following documents such as
specifications or instruction manual of this product, or, if MAYEKAWA judges that malfunctions or
damages are related to design or manufacture of the product, and if the malfunctions or damages are
within the warranty period, MAEKAWA will repair this product or replace parts without any charges.
The warranty period is “12 months from factory shipment of this product”. However, if any separate
agreement has been concluded, such an agreement will have the priority in principle.
Disclaimer Clauses (Exclusion of Warranty Clauses)
Please note that we disclaim any responsibility for malfunction and/or damage to this product in case of
the following incidents:.
Malfunction or damage of this product caused by force majeure such as windstorm, intense
rainfall, flood, tidal wave, earthquake, land subsidence, thunderbolt, fire, etc.
Malfunction, damage, or defect to this product due to abuse or misuse such as storing this
product outdoors or in hot and humid locations, operation with excessive liquid flow-back and
start-and-stop.
Malfunction or damage caused by devices or equipment not provided by MAYEKAWA
including operation control methods of those devices or equipment.
Malfunction or damage due to operation of this product outside the operation limits as
described in this manual.
Malfunction or damage caused by the usage of refrigerants, gases, and/or lubricants which
are not approved by MAYEKAWAfor this product as described in this manual.
Malfunction or damage caused by maintenance or inspection procedures which are not
recommended by MAYEKAWA.
Malfunction or damage caused by parts which are not MAYEKAWA genuine.
Malfunction or damage caused by parts which are not MAYEKAWA genuine.
MAEKAWA shall not be liable to buyer for any incidental, indirect, special or consequential
damages that buyer may suffer in relation to this product.

Important Information
UD-series Screw Compressors
iii
Important Information
Intended Use of this Product
This product is a screw compressor intended use for freezing and refrigeration.
Do not use this product for any other purposes for which it is not intended or deviate from the
specifications which are described in Chapter 2, Article 2.3 “Compressor Specifications”.
The maintenance service should be performed according to the procedures described in this manual.
Always pay attention to perform the works in a safe manner and working environment.
Important Information for Safe Use of This Product
Although MAYEKAWA has paid a lot of attention to safety measures for this product, all hazards
including potential hazards caused by human errors, or due to environmental conditions can not be
anticipated.
There are guidelines that must be followed to ensure proper use of this product. However, the warnings
in this manual and safety labels on this product are not all inclusive. When operating the product, pay
extreme caution on personnel safety as well as on items described in this manual or required by
common safety practice.
Important rules for safety work with the product that apply to all workers including managers and
supervisors are listed below.
Before using this product, carefully read and fully understand the contents written in this manual and
pay attention to safety.
Operation, maintenance, and inspection of this product should be performed by qualified
personnel educated about the fundamentals of the product and trained about hazards
involved and measures to avoid danger.
Do not allow any person other than those educated on the fundamental expertise of the
product and trained about hazards involved and measures to avoid dangers to approach the
product while it is operating or during maintenance.
Observe all related federal/national and local codes and regulations.
To prevent accidents, do not carry out any operation or maintenance other than those
described in this manual, or use the product for any unapproved purpose.
Replace the parts with the genuine parts.
Not only workers but also managers should actively participate safety and health activities in
the workplace to prevent accidents.
When closing or opening valves during work, apply lockout/tagout without failure, to prevent
the valves from closing or opening accidentally during the work.
[Lockout] To lock with a key in order to keep people, except the workers involved, from
operating the product.
“Lockout” is a safety procedure to make sure that machines or equipment are property shut off and
not able to be started up again by locking the power source to them.
Lockout is not just simply turning off the switches to stop the power supply, but includes immobilizing
them with a key or similar device to prevent unauthorized access.
Lockout devices are devices such as keys, covers, and latches, to immobilize and shut-off switches,
valves, opening and closing levers, etc.
[Tagout] To prevent any inappropriate work by hanging tag plates indicating like “work in
progress”.
“Tag-out” means to clearly indicate that a device is in lockout and that operation of the device is

Important Information
UD-series Screw Compressors
iv
prohibited. The sole purpose of the tag plates such as prohibition of operation or commissioning is to
warn others that it is prohibited to operate the locked out product. It should always be accompanied by
a suitable lockout device to make operation impossible.
Observe the following precautions when performing maintenance work on electrical control.
Electrical maintenance of the product must be performed by certified/qualified personnel and
only those who have been trained in the potential danger and its avoidance relevant to the
electrical control of the product.
Before servicing or inspecting the electrical equipments or devices, turn "OFF" the motor main
power and control power, and perform lockout/tagout to prevent the power from being turned
on during work.
During maintenance work, make sure that the power supply on the power source side is shut off and
perform lockout/tagout to prevent the product from being accidentally turned on.
About this Manual
This product may be modified without prior notice. Therefore, the appearance of actual
machine may differ from the descriptions in this manual. If you have any questions contact
your sales offices or service centers. For each sight of MAYEKAWA, refer to following URL.
http://www.mayekawa.com/about/network/
This manual is in English. If any other language is required it is the customers responsibility to
prepare a manual for safety education and operation instructions.
This manual is copyrighted. Drawings and technical references including this manual shall not,
in whole or part, be copied, photocopied, or reproduced into any electronic medium or
machine-readable form without prior permission from MAYEKAWA.
Photographs or drawings included in this manual may differ from the appearance of actual
product.
If this manual is lost or damaged, immediately place a purchase order to your local sales office
or service center for a new manual. Using the product without the manual may result in safety
issues.
In the event that this product or the compressor package is resold, don’t forget to supply this
manual together with the product.
Construction of this Manual
Title of section and
chapter
Description details
Preface Describes the outline of this manual and how to read it.
Warranty and Disclaimer
Describes clauses and coverage of warranty.
Exemption of warranty clauses is described as disclaimer.
Important Information
Describes important information related to this product and this
manual.
1. Safety
Describes safety information for the worker, safety rules for this
product, and management details regarding wor
k safety required for
handling the product.
2. Structure and Specifications
of the Compressor
Describes the main components of this product, functional
information, specifications, and operating limits.
3. Installation
Describes installation procedure of this product.
4. Compressor and Package
Operation
Describes precautions for operating this product.

Important Information
UD-series Screw Compressors
v
Title of section and
chapter
Description details
5. Maintenance and Inspection
Describes sections and period for inspecting, disassembly and
assembly of the product.
6. Troubleshooting
Describes troubleshooting methods for the product in case problems
occur during operation of the product.
7. Related Documents
Describes documents such as illustrated parts breakdown and parts
list.

Table of Contents
UD-series Screw Compressors
vi
Table of Contents
Preface........................................................................................................................i
Revision history.....................................................................................................i
Warranty and Disclaimer ...........................................................................................ii
Warranty Clauses.................................................................................................ii
Disclaimer Clauses (Exclusion of Warranty Clauses)...........................................ii
Important Information...............................................................................................iii
Intended Use of this Product............................................................................... iii
Important information for Safe Use of this Product.............................................. iii
About this Manual...............................................................................................iv
Construction of this Manual.................................................................................iv
Table of Contents......................................................................................................vi
Chapter 1 Safety
1.1 Observation/Prevention.............................................................................1-1
1.1.1 Observance (Do’s).............................................................................................. 1-1
1.1.2 Prohibitions (Don’ts) ........................................................................................... 1-3
1.2 Warnings.....................................................................................................1-4
1.2.1 Types and Meanings of Warnings...................................................................... 1-4
1.2.2 Safety labels ....................................................................................................... 1-4
1.3 Residual Risks............................................................................................1-6
1.4 Safety Devices............................................................................................1-9
1.4.1 Emergency Stop Button...................................................................................... 1-9
1.4.2 Breakers for the Main Motor Power and Control Power..................................... 1-9
1.4.3 Compressor Protection Devices ....................................................................... 1-10
Chapter 2 Compressor Specifications and Structure
2.1 Features of UD-series Screw Compressors .............................................2-1
2.2 Model Designation of the Compressor .....................................................2-2
2.3 Compressor Specifications .......................................................................2-4
2.3.1 Standard Specifications...................................................................................... 2-4
2.3.2 Operation Limits.................................................................................................. 2-5
2.3.3 Outer Dimensions and Weight............................................................................ 2-7
2.4 Compressor Structure and Mechanism..................................................2-10
2.4.1 Overview of UD-series Screw Compressor......................................................2-10
2.4.2 Refrigerant Gas Compression Mechanism....................................................... 2-11
2.4.3 Internal Volume Ratio Vi................................................................................... 2-13
2.4.4 Bearings and Balance Piston............................................................................ 2-17

Table of Contents
UD-series Screw Compressors
vii
2.4.5 Shaft Seal ......................................................................................................... 2-17
2.4.6 Capacity Control ............................................................................................... 2-17
2.4.7 Oil Supply Route............................................................................................... 2-17
Chapter 3 Installation
3.1 General Installation Precautions...............................................................3-1
3.2 Installation Works.......................................................................................3-1
3.2.1 Unpacking........................................................................................................... 3-1
3.2.2 Storage ............................................................................................................... 3-1
3.2.3 Transportation..................................................................................................... 3-1
3.2.4 Preparation for Installation.................................................................................. 3-3
3.2.5 Installation........................................................................................................... 3-7
3.2.6 Airtightness Test................................................................................................. 3-9
3.2.7 Vacuuming.......................................................................................................... 3-9
3.2.8 Lubricating Oil Charge........................................................................................ 3-9
3.2.9 Charge of Refrigerant ......................................................................................... 3-9
3.2.10 Checkout after Installation ..........................................................................................3-9
Chapter 4 Compressor and Package Unit Operation
4.1 Lubricating Oil (Refrigerant Oil)................................................................4-1
4.1.1 Precautions for Selecting the Lubricating Oil...................................................... 4-1
4.1.2 Change of Lubricating Oil Brand......................................................................... 4-2
4.1.3 Precautions for Handling lubricating Oil ............................................................. 4-2
4.1.4 Lubricating Oil Control Criteria............................................................................ 4-3
4.1.5 Lubricating Oil Replacement Timing................................................................... 4-4
4.2 Precautions for Operation .........................................................................4-5
4.2.1 Prevention of Liquid Flow-back Operation.......................................................... 4-5
4.2.2 Purging of Non Condensable Gases.................................................................. 4-5
4.3 When Stopping the Compressor for a Long Time....................................4-6
Chapter 5 Maintenance and Inspection
5.1 Precautions for Maintenance and Inspection...........................................5-1
5.2 Maintenance and Inspection List ..............................................................5-3
5.2.1 Daily Management.............................................................................................. 5-3
5.2.2 Periodic Inspection ............................................................................................. 5-5
5.2.3 Guidelines for the Timing of Compressor Overhaul ........................................... 5-6
5.3 Compressor Disassembly Preparation.....................................................5-7
5.3.1 Disassembly Tools and Workplace .................................................................... 5-7
5.3.2 Replacement Parts ............................................................................................. 5-8
5.3.3 Refrigerant Gas Recovery................................................................................ 5-10
5.3.4 Removal of Connections to the Unit................................................................. 5-10
5.3.5 Removal of the Compressor from Base Flame ................................................ 5-12
5.3.6 Compressor Disassembly Order....................................................................... 5-13
5.4 Disassembly and Inspection ...................................................................5-14

Table of Contents
UD-series Screw Compressors
viii
5.4.1 Unloader Indicator Block................................................................................... 5-14
5.4.2 Shaft Seal Block................................................................................................ 5-17
5.4.3 Shaft Seal ......................................................................................................... 5-19
5.4.4 Unloader Cover................................................................................................. 5-20
5.4.5 Unloader Piston and Unloader Cylinder ........................................................... 5-23
5.4.6 Removal of Bearing Cover................................................................................ 5-24
5.4.7 Thrust Bearings................................................................................................. 5-25
5.4.8 Balance Piston Cover ....................................................................................... 5-32
5.4.9 Balance Piston.................................................................................................. 5-33
5.4.10 Oil Injection Pipe............................................................................................... 5-36
5.4.11 Suction Cover and Side Bearing....................................................................... 5-37
5.4.12 Rotor and Rotor Casing.................................................................................... 5-38
5.4.13 Bearing Head and Main Bearing....................................................................... 5-40
5.4.14 Unloader Slide Valve and Guide Block............................................................. 5-41
5.5 Reassembly ..............................................................................................5-42
5.5.1 Unloader Slide Valve and Guide Block(125-320)............................................. 5-42
5.5.2 Bearing Head and Main Bearing....................................................................... 5-43
5.5.3 Rotor ................................................................................................................. 5-44
5.5.4 Suction Cover, Side Bearing and Oil Injection Pipe ....................................... 5-45
5.5.5 Balance Piston Sleeve...................................................................................... 5-50
5.5.6 Balance Piston Cover ....................................................................................... 5-52
5.5.7 Thrust Bearing Block ........................................................................................ 5-52
5.5.8 Bearing Cover................................................................................................... 5-60
5.5.9 Unloader Piston and Unloader Cylinder ........................................................... 5-60
5.5.10 Unloader Cover................................................................................................. 5-62
5.5.11 Shaft Seal Block................................................................................................ 5-64
5.5.12 Disassembly and Assembly of the unloader Indicator...................................... 5-65
Chapter 6 Troubleshooting
01: Compressor does not start up.................................................................................... 6-1
02: Compressor stops immediately after startup............................................................. 6-1
03: Abnormally low pressure............................................................................................ 6-2
04: Low oil-supply pressure............................................................................................. 6-2
05: Abnormal high pressure............................................................................................. 6-3
06: Abnormally high discharge temperature.................................................................... 6-4
07: Leak from mechanical seal........................................................................................ 6-5
08: Squeaking sound from mechanical seal part............................................................. 6-6
09: Faulty indication of capacity control position ............................................................. 6-7
10: Capacity control malfunction...................................................................................... 6-7
11: Abnormal vibration and/or noise of compressor........................................................ 6-8
Chapter 7 Related Documents
7.1 Exploded Views, Sectional Views .............................................................7-1
7.2 Parts Configuration Table..........................................................................7-8
Table 7-1 Parts Configuration Table of 125*UD models ................................................. 7-8
Table 7-2 Parts Configuration Table of 160*UD models ............................................... 7-12
Table 7-3 Parts Configuration Table of 200*UD models ............................................... 7-16

Table of Contents
UD-series Screw Compressors
ix
Table 7-4 Parts Configuration Table of 250*UD models ............................................... 7-20
Table 7-5 Parts Configuration Table of 320*UD models ...............................................7-24
Table 7-6 Parts Configuration Table of 400*UD models ............................................... 7-29
7.3 Maintenance Data.....................................................................................7-33
7.4 Lock Nuts..................................................................................................7-35
7.5 Thrust Bearing Gland...............................................................................7-36
7.6 O-rings Used.............................................................................................7-37
7.7 Gaskets Used............................................................................................7-38
7.8 Tools for Disassembly .............................................................................7-39