Manufacturer of Air Compressor change & innovation

VENDOR AIR COMPRESSOR

INSTRUCTION MANUAL

NEX-A
NEX A SERIES

A 2012.03.02 For Estimate D.S Kim - C.H Yun

Rev. No. Date Description Prep. By Chk’D By App’D By

DONGHWA PNEUTEC CO., LTD. 1

INTRODUCTION & GENERAL change & innovation

Introduction

We wish to appreciate you for choosing this DongHwa Pneutec’s NEX-series Compressor
(Oil Injection Screw Compressor).

● Before installation and starting operation of the compressor, be sure to read this instruction
manual carefully to understand the contents.
● Keep
p the manual in the p
place where it is available whenever necessary.
y
● If you lost or damaged this manual, be sure to order the same.
● In case of transferring the compressor, this manual should be handed over to the next owner.
● Information contained in this manual is subject to change without notice for improvement.
● “Model and type No.”, “Serial No.”, and “INST. No. of this instruction manual” should be
informed when making inquiry on the compressor.
● Do
D nott remodel
d l th
the compressor without
ith t our permission.
i i W
We assume no responsibility
ibilit ffor th
the
remodeling.
● The Compressor have finished a performance test from the Donghwa Pneutec so don’t prohibit
a random or arbitrary operate and disassembly regarding components.
● This manual is normal regarding a compressor specification so can be a little change according to
components and option specification.

General
● Features :
DongHwa Compressors, Model NEX-series are air-cooled single stage screw compressor
which
hich are mainly
mainl used
sed to the ser
service,
ice control and also used
sed for the general p
purpose
rpose such
s ch as
pressure test.

● Construction :
The compressor consists of the following components: driving unit governed by power supply,
air
i compressing
i unit,
it air-cooling
i li unit
it to
t cooll the
th compressed
d air,
i air
i receiver
i thank
th k to
t store
t the
th
compressed air(Option), and control panel to control the compressor.

! ＊＊ For air receiver tank or auxiliary equipment that provided by the user,
be sure to check that they conform to the specifications
specifications.

2
Index change & innovation

IIntroduction
t d ti
General
Index

1. Safety Attention
1-1. Notice before Operation
1-2. Notice during Operation
1-3. Notice for Maintenance & Check
1-4. Position to stick Warning Label
1-5. Warning Label

2. Term and Function of Each Part

3. How to Install
3-1. Confirmation of Product
3-2. Notice for Transportation
3-3. Notice for Installation
3-4. Notice for Piping
3-5. Notice for Wiring

4. How to Operate
4-1. Test Run of Compressor
4-2. Daily Operation
4-3. Control System

5. Check and Maintenance

5-1. Periodical Maintenance of Compressor & Notice after Maintenance
5-2. Daily Check & Operation Record
5-3. Standards & List for Compressor Maintenance
5-4. Know-how of Check & Maintenance
5-5. Daily Maintenance Record Sheet

6. Causes of Troubles and Troubleshooting

7. Machine Long-term Storage

8. Warranty

3
1. Safety Attention change & innovation

Mishandling of the oil injection screw compressor may cause a fire or electric-shock accident. Before
installation, operation, or maintenance check, be sure to read this manual carefully and make correct
operation. Operate only after acquiring all of knowledge about the machine, safety information, and
directions. The marks of Warning
g and Attention emphasize
p critical and important
p information.

About the Marks of Warning and Caution

This indicates that, if one mishandles against this mark, he/she may die
or receive a serious injury.

This indicates that if one mishandles against this mark, he/she may
receive an injury or property damage may occur.

◆ Serious Injury: It refers to loss of sight, a wound, a burn (high/low temperature), dislocation,

intoxication, etc. which leave aftereffects and require hospitalization or a long-term hospital visit.

◆ Injury: It refers to a burn, an electric shock, etc. which do not require hospitalization or a long-term

hospital visit.

◆ Property Damage: It refers to expanded damage related to property destruction and mechanical

damage.

Such safety attention is a suggestion providing more important points about the DONGHWA PNEUTEC
oil injection screw compressor. Our customer is requested to establish safety measures in accordance
with all sorts of standards for operation & maintenance, for the safety of machine and equipment.
DONGHWA PNEUTEC does not take responsibility
p y for results arising
g out of disregard
g for such safetyy
attentions.

4
1. Safety Attention change & innovation

1-1. Notice before Operation

[ Danger ]

● Don’t use with the object of CPR using the compressed air for body.
Th C
The Compressed
d air
i hhas carbon
b monoxide,
id pollutant
ll and
d so on. IIt can b
be get
from serious injury to death while it use for breath action.
● This compressor isn’t design with the object of diving working or air
compression pressurization structure method.
● Don’t use the compressed air with the object of breath action for diving air tank compression
and so on.
Customer can death during diving while the compressed air breathe.

[ Warning ] Comply to safety rule

● Comply
C l with
ith read
d a manuall and
d nameplate
l t contents
t t carefully
f ll .
● Retain clean condition about a warning label.
Put a new label in case damage or miss.
● No transform a compressor without prior permission.
It can be curtail a compressor’s life-span and the safety can be worse
and the function can be a decrease.
● Don’t use a vacuum pump or a gas compressor excepting air use about compressor.
It can be occur a serious accident.

[ Warning ] Retain a rest mental and physical health.

● Don’t use a compressor in a dose of medicine and drink of alcohol and tire state.
Careless a compressor use can an accident or a sudden injury.
Customer shall be carefully handle in a stable state from mental and physical health during
use a compressor.

5
1. Safety Attention change & innovation

[ Alarm ] Safety Clothes

● Don’t wear a baggy clothes while customer use a compressor.

● Close a sleeve button surely.
● Don’t fasten up a necktie and a scarf.
● Avoid to an accessories.
Otherwise customer or engineer can be a serious injury so clothes get
jammed in a compressor or reel.

[ Caution ] Safety Device

● Please put on a helmet, safety glasses, earplug, safety shoes,

safety gloves and mask surely.

[ Caution ] Safety Tools

● Store the fire extinguisher at a near by a compressor and

first-aid kit box prepare for emergency such as injury of fire
● Store a compressor at a near by a phone number of a doctor, an
ambulance the fire station prepare for emergency
ambulance, emergency.

[Caution ] Transportation

● Use the crane surely when a compressor transportation.

● Also, fix to tie up a rope, if needs, put a wooden support in the bottom of truck.

6
1. Safety Attention change & innovation

● Notice for Installation

[ Alarm ]

● Use a compressor at a near by in place without a fire, explosion component, a organic solvent,
a flammability gas (acetylene, propane gas and so on), explosiveness.
● Don’t use a compressor in place to inflow a salt, humid, moisture of rain and steam.
(short circuit, grease life-span fall, cause of production’s life-span decrease)

[ Caution ]

● Don’t use a compressor in place like a corrosiveness of ammonia, acid, salt, ozone gas, sulfurous
acid gas and oil, oil mist. (life-span decrease, cause of damage)
● Don’t use a compressor in place like a alien substance of iron, dust, chips of wood, flocks.
(early pollution of suction filter and cooler, temperature rise of compressor, life-span decrease)
● Check-out the main power of rated voltage, 220/380,440V(50/60Hz). Also, use a rated frequency
surely. (operating faulty, cause of motor damage)
● Carry out the grounding work surely. (short circuit, electric shock)
● Remove the transportation tools just before operating surely. (strange vibration, damage)

[ Warning ] Installation

● A compressor have to install a flat ground of indoor so as not to incline. A compressor become the
cause of a vibration and noise in such a case gap between a compressor and bottom.

[ Alarm ] Test before a compressor operating

● Test a compressor before operating surely. If a problem was discover, it is stop a power and use
after repair.
● Test and check-out a compressor everyday before operating.
If compressor is occur a problem for neglecting during operating, it can be cause of the fire as well
as damage
d iin compressor.

7
1. Safety Attention change & innovation

[ Warning
W i ] Wiring
Wi i

● Install the ground fault circuit in a compressor power supply wiring in order to short circuit
protection surely.
Use only a rated circuit in the power supply surely.
Engineer
g or customer can be cause of accident a electric shock and the fire if the capacity
p y of p
power
circuit isn’t enough or electric work don’t.
● Bury an earth bar ground. Don’t connect a gas piping and water piping or existing iron structure.
● Wiring no hang or step outward a cable.

1-2. Notice during Operation

[ Caution ] Cooling Fan Caution

● Don
Don’tt take a hand at a near by a cooling fan during operating.
Engineer or customer can be cause of a serious injury if your hand
get jammed.

[ Caution ] Rotation part(Reel) and Belt Caution

● Don’t take a hand at a near by a reel and belt when operating.

Engineer or customer can be cause of a serious injury
if your hand get jammed.

[ Caution ]

● Don’t spray the compressed air toward peoples.

Engineer or customer can be cause of a serious injury for skin
and an eye from all sorts of pollution material in the middle of
the compressed air
air.

8
1. Safety Attention change & innovation

[ Warning
g ] Fire Prevention

● Don’t put all sorts of oil surroundings a lighted cigarette or

match in every possible case.
Oil shall be handle with care so inflammables are very dangerous.
● Store the fire extinguisher at a near by a compressor for a fire.

[ Warning ] Don’t touch a red-hot parts

● Don’t touch red-hot parts in case carry out a check-out

during a compressor operating.
Be careful a burn so hot discharge piping and etc.

[ Warning ]

● Contact with Donghwa Pneutec’s agency or supplier in case get damaged or no working order
and it shall not be operating a compressor.
● If pressure of air receiver tank is decrease in case a compressor was stop in the operating state,
a compressor is start automatically.
Don’t take a hand and face at a near by a reel(belt, fan) when operating and switch ON.
● The compensation pressure valve and cooler, connection piping of tank, discharge piping and air
end by operating is high temperature.
Don’t touch the compensation pressure valve and cooler, connection piping of tank, discharge
piping and air end after operating stop and during operating
operating.

1-3. Notice for Maintenance & Check

[ Caution ] Hang up the mark “during

during check-out
check out and maintenance
maintenance”.

● Hang up the mark “during check-out and maintenance” noticeable and

shut off the power before carry out a check-out.
Inspector shall be store the key during check-out and maintenance surely.

9
1. Safety Attention change & innovation

[Caution ] Electric Shock

● Don’t touch the electric device or power supply source with wet hands.
Engineer or customer can be a serious accident or until a death
if receive an electric shock.

[ Caution ] The Compressed

p Air Explosion
p Caution

● The compressed air can remain within cooler and discharge piping.
Check-out the pressure gauge 0Mpa(0 kgf/cm2) after a compressor
operating is stop.
Discharge remaining the compressed air within piping and open the
service valve once after a compressor operating is stop.
● Operator can be a serious injury by explosion of remaining the
compressed air getting pressure.

[Caution ] Air Spray Cleaning

● Engineer of customer shall be wear a safety glasses in order to

protection an eye in case removing a burden of dust within devices of air
filter etc, with the compressed air spray.

[ Warning ] Fire

● Check-out periodically the devices surely such as motor.

The fire can be occur if oil is overheat for neglecting a check-out

10
1. Safety Attention change & innovation

[ Warning ]

● Carry out a check-out and maintenance periodically.

● Engineer or customer shall be shut off a main power during a check-out and maintenance surely
and remove a pressure of air receiver tank.
● Don
Don’tt use beyond a change period
period. Engineer or customer shall be carry out a check
check-out
out and
maintenance early according to use situation and contact with Donghwa Pneutec or supplier.
● Don’t convert a parts or component and production or disassembly a isolation parts and safety
device.
● Use the Donghwa Pneutec’s articles of the best quality in case change a parts surely.

[ Caution ]

● Carry to unload operating in case again operating after compressor operating is stop beyond
1 month.

11
1. Safety Attention change & innovation

1-4. Position to stick Warning Label

12
1. Safety Attention change & innovation

1-5. Warning Label

＊＊ This compressor is provided with five warning labels to be stuck.

＊＊ In case the label is damaged, peeled off, or discolored, be sure to order

a new label
l b l and
d stick
ti k it
it.

Do not touch the electrical equipment and wirings without reasons.

Be sure to disconnect the both of main power supply and operating power
supply during repair and maintenance. Work with the wet hand is
dangerous.

Do not touch the electrical equipment and wirings without reasons.

Be sure to disconnect the both of main power supply and operating power
supply during repair and maintenance.
maintenance Work with the wet hand is
dangerous.

V-Belt or coupling is rotating at high-speed in the cover. Never put the

hand in the cover. Hand will be entangled.
Disconnect both of main power supply and operating power supply, then
remove the cover when starting the work.

Compressed air or oil spouts when pressure is being applied or when

pressure remains.
When starting work, make sure no pressure is left in the compressor after
it was stopped.
t d

The compressor is hot during operation and immediately after the

stopping.
Do not touch. Work with it after completely cooled.

13
2. Term and Function of Each Part change & innovation

■ Term and Function of Each Part

EXHAUST
OIL & AFTER
COLLER
OPERATING
MIM.PRESSURE PANEL
VALVE
FAN MOTOR
PRESS.SENSOR

PANEL
AIR FILTER
&CASING

SUC.CONTROL
VALVE

AIR END
VIBRATION
PROOF
RUBBER

AIR OUTLET
TEMP.SENSOR

SAFETY VALVE

OIL
COOLING FAN SEPERATOR
&TANK
MAIN MOTOR SUPPLY OIL
HOLE
AIR IN
OIL GAUGE

CABLE INLET
OIL FILTER

OIL DRAIN

14
3. How to Install change & innovation

3-1. Confirmation of Product

1) Make sure whether the model, voltage, and frequency on the name plate are the same as ones
you ordered.
2) Make sure whether there was no breakage or deformation during transportation.
3) Make sure whether there are all the accessories.

15
3. How to Install change & innovation

3-2. Notice for Transportation

(1) Site & Installation

[ Caution ] Installation
● A compressor shall be install a flat ground of indoor so as not to incline. A compressor become the
cause of vibration and noise in case gap between compressor and ground.

● A compressor shall be operate below next condition :

Ambient Temperature ……………. 0℃ ~ Max. 50℃ (Maker Standard)
Humidity …………………... 0 ~ Max. 100%
Height …………………... Below 1,000 from sea level

● Install a compressor in dry indoor possible and well ventilate, a low temperature & humidity.
● If a compressor install in many humidity such as basement, It become the cause of short circuit and
corrosion.
● Do inhale always clean air and install a compressor of the lowest dust occurrence in clean place possible.
● A compressor shall be install avoid to exhaust place from toxic gas such as chlorine gas, hydrogen
sulfide gas, sulfurous acid gas and highly enriched ozone. Such a toxic gas give rise to oil aging and
a component corrosion
corrosion.
● A compressor shall be install a flat ground of indoor so as not to incline. A compressor become the
cause of vibration and noise in case gap between compressor and ground.

(2) Ventilation

1) Ventilation using a fan

If a compressor install no ventilation place, a compressor shall be install using a ventilation fan
of many capacity more than right schematic in order to keeping below
indoor room temperature 40℃.
* This fan capacity assume when indoor room temperature is a rising range 5℃
and
d reference.
f
This fan capacity can be change according to indoor room size of compressor
installation.

2) Install using a ventilation fan of many capacity more than ventilation capacity
of ② when it install duct inside an exhaust p
piping.
p g
Install a duct of widen space more than a duct diameter and install a hood type
in suction duct. Don’t connect a duct directly in a compressor air discharge port
in such a case.

16
3. How to Install change & innovation

3-2. Notice for Transportation

(3) Space secure for check-out and maintenance

● Engineer and customer shall be secure the requisite space in and around a compressor for check-out
and maintenance.
● It needs to space
p degree
g of enough
g moving
g compressor
p cover.
● A compressor installation shall be an enough space in and around a compressor for overhaul

(4) Transportation

● Carry out method like below next paragraph in order to protection of production so a compressor can be
occur a transform and fall during transportation.

[ Caution ] Transportation

● Use a crane during a compressor move or transport surely.

● Fasten your rope(1) when a compressor transport by truck.
In case need, Fix your a cross tie(2).

[ Notice ]
● If engineer or customer would like to move and change a position of a compressor, please load by
truck using a cross tie.
● Please choose a truck enough capacity of the same or excess a weight and size of a compressor
and refer to this manual specification
specification.
● Operate a crane by a skilled worker.

17
3. How to Install change & innovation

3-2 Notice for Transportation

3-2.
● In case transportation using a forklift

① Transport or move using pad to preventing damage like scratch of cover when it transport by a forklift.
② Check-out whether to operation possibility scope and check-out use load of a forklift.
③ Don
Don’tt too incline a forklift foothold
foothold.
④ Transport or move slowly so as not to damage for safety of production.

Protect a damage of production put a cushion of schematic 1.

Stick out a forks from pallet hole of schematic 2.

● Case of transportation hanging by crane

① Check-out whether to operation possibility scope and check-out use load of crane.
② Maintain below the angle 60 of wire when a compressor lift by crane.
A compressor can be get twist a package or I-bolt in case short a wire.

● Don’t damage a compressor, lift up a machine using of crane

put a cushion in “1” between a compressor and crane rope.
Put a cushion in “2” in proper face in order to not damage in package.
Check-out a surrounding persons before lifting a compressor.
Be careful not fall when lifting a compressor so center of a compressor
weight is a little to much to left position.

Compressor load and unload

Load and unload a compressor in flat ground enough to endure.

18
3. How to Install change & innovation

3-3. Notice for Installation

1) A compressor can’t be install a outdoor. A compressor shall be install a indoor.

2) A compressor shall be install a good place of ventilation and bright, wide, a small dust.
Otherwise a filter element can be short a life span.
3) A compressor shall be avoid a lot of humid place . It can be short a life span so mixed drain
water with oil.
4) A compressor shall be avoid a place more than a surrounding temperature 45~50 ℃.
5) A compressor shall be install a flat ground place. It can be the cause of strange vibration and noise.
6) A compressor installed with mounting for vibration prevent in common base of air end and motor.
So it is not needs foundation.
foundation
7) A compressor shall be secure a space in order to avoid to temperature rise, check-out of a production and
maintenance.
8) Carry out implement a indoor ventilation put an exhaust port on the upper and an suction port in the lower.
It is structure that can be exhaust on the upper and suction in the lower inner machine from fresh the air.
9) Secure a maintenance space that it shall be secure beyond 1m from front, rear, right, left of production.

※ Contact with a Donghwa Pneutec or a purchaser in case difficult of space secure.

19
3. How to Install change & innovation

3-3. Notice for Installation

1. Install indoors in a bright, spacious, dry, and well-ventilated place.
2. In consideration of temperature rising and maintenance, secure space shown below.
3. According to the structure, fresh air is taken in from the bottom, and air is taken out of the top. So, for
ventilation, place suction and exhaust apparatus as shown in the diagram below.
※ If it is difficult to secure space,
space consult your place of purchase or DONGHWA PNEUTEC
PNEUTEC’s
s head office.
office

Ventilation·Exhaust
Ventilating Fan Space
• Be sure to use a • Secure ventilation
space.
ventilating
g fan which
has a capacity more • If exhaust
h t space is
i
Exhaust insufficient, exhaust
than necessary.
resistance increases
and temperature inside
1.5m or the equipment rises,
more which causes the
shortening of every
80cm or Exhaust component's life.
more
Suction Space Back Space
• Secure
S space ffor good
d Suction
ventilation. • Secure space for
80cm or opening the door and
more checking.
1m or
Maintenance Space more Suction
Suction·Piping Space
• Secure space for
opening the door and
80cm or • Secure sufficient air-
more suction space.
checking.

( * When installed in a borrow place or closed room. )

! Warning

™ Installing at a high place may cause the falling of the product or the falling of parts during maintenance.
D nott install
Do i t ll att a high
hi h place.
l

20
3. How to Install change & innovation

3-3. Notice for Installation

4 Install on a horizontal bottom surface.
4. surface
! Attention
Install on a horizontal • Do not install on a bottom of insufficient strength. Nor
bottom surface which install on a pallete or a box. (The cause of abnormal
has sufficient strength.
vibration, noise, or breakage)
• Donot fasten to a concrete surface, etc. by force.
Rubber Plate (The cause of abnormal vibration, breakage)
• If there is any space
from the bottom, put
a rubber plate, etc.
into it so that there is
not any gap.

5. In the event of installing several compressors together, make arrangements that

exhaust g
gas of one machine does not enter the suction p
part of the others.

! Warning ! Attention
Operation or installation at the following places are In the following places, the life-shortening of the product or
very dangerous. Be sure to avoid them. disorder may be caused. Prohibit installation or use.

A place exposed to water such as rain or vapor. A place of A place where ammonia, acid substance, salt, or
high humidity. (The cause of a short-circuit, rust in parts, and corrosive gas such as sulfurous acid gas exists; a
life shortening) place having much oil or oil mist. (The cause of rust,
life shortening, or breakdown)

Prohibited Prohibited

A place having no explosive, inflammable gas Applace exposed

p to a foreign
g substance such as iron content,,
(acetylene, propane gas, etc.), an organic solvent, sands, dust, sawdust, a piece of thread, etc. (The cause of
explosive dust, or heat of fire nearby. (The cause of a breakage, and the early blockage of suction filter element or a
inner-cooler cooling pin, etc., whereby the temperature of the
fire accident)
body rises and life is shortened.)

Prohibited
Prohibited

21
3. How to Install change & innovation

3-4 Notice for Piping

3-4.
(1) Requirement for safety

[ Caution ] Caution for piping work

● Avoid the lower part of piping line and install a drain valve under joint surely because of drain water
can be a discharge, in case needs the L-type vertical joint. If drain water isn’t a discharge, piping is
cause of injectionze and burst.
● Install a drain valve in order to prevent backward to compressor from main discharge piping.
● Engineer and customer shall be consider a maintenance when a piping line arrange.

[ Notice ]
● install a service valve between a stop valve and a compressor.
And install stop valve in main discharge piping in order to test-run, alignment, maintenance.

● Vendor is recommend that engineer and customer shall be use to discharge piping of no oil piping.
● Install adjust connection piping and flange to compressor disassemble when it connect a gas piping directly
directly.
● Engineer and customer shall be minimize elbow number of compressed air piping, joint, valve consider
of pressure loss decrease.
● Engineer and customer shall be decision diameter of discharge piping consider pressure loss of inner
piping in case a discharge piping length long.
● Connection piping size consider of pressure loss prevention that it must be beyond or equal size like
compressor discharge piping.
● Install stop valve in discharge piping of a compressor when a compressor is installs beyond 2 set.
Also, Close automatic valve of motor-operated valve during a compressor stop and in case automatic shift
operation, automatic valve like motor-operated valve exchange to a stop valve.
● Engineer and customer shall be install drain valve under piping in case vertical piping or uneven part in
piping Drain water can be accumulate under piping.
piping. piping
● Connect use of union joint or flange so a compressor discharge part is easy a moving and disassemble,
maintenance after installation of a compressor.

22
3. How to Install change & innovation

3-4 Notice for Piping

3-4.
(2) A special installation of air receiver tank

● Install a air receiver tank so capacity control system is 0% and 100% of 2stage type.
If a compressor is operate no air receiver tank, a compressor is short long-span owing to overload and
unload operation
p change
g repeatedly.
p y
● Vendor is recommend that it is connect a screw compressor in discharge piping of air receiver tank so
vibration of reciprocating compressor not travel to a screw compressor, when a screw compressor operate
parallel to reciprocating compressor.

[ Installation example ]

23
3. How to Install change & innovation

3-4 Notice for Piping

3-4.
(3) Drain piping

1) Connect each manual or auto drain valve between cooler and clean-air-unit.
Also, arrange and align of discharge port in order to decrease a compressed air.
2)) It is difficult check a drain water whether drain or no drain so drain p
piping
p g is g
group
p each component
p and
another machine, no drain because of pressure difference of drain water.
3) A drain water of cooler comes out drain through orifice continuously.
So engineer and customer shall not be install that valve like automatic drain valve in drain port of cooler.
4) Engineer and customer shall be drain a cooler discharge port on the cooling or drain water level.
It is cause of absorb a cooling or drain water when unload operation, if discharge port beneath
a cooling or drain water.

[ Notice ]

● Engineer and customer shall be coincide with next data in order to prevent pressure loss about piping
diameter
● Use a piping next diameter in order to prevent pressure loss.
Below 10m : more than 25A(1B), Below 10m : more than 50A(2B)
Engineer and customer shall not be put outdoor piping nearby a ventilation fan suction port.
It is cause of inhale to suction port about oil mist.

24
3. How to Install change & innovation

3-4. Notice for Piping

p g
(4-1) Directions for General Piping Work

① As for discharge line, use pressure piping ⑤ Install a stop valve at the discharge line.
materials from which oil is removed.
⑥ In case of a vertical pipe, keep it about 500
② When connecting directly to piping, connect by mm and more from the surface of the
means of union or flange so that the soundproof cover, in consideration of the
disassembly of the compressor may be easy
easy. maintenance of compressor
compressor.

500mm or
more

③ When discharge line is long, select the size of ⑦ In the event of connecting the discharge line to
pipe in consideration of pressure loss within a the main line, connect the discharge line from
pipe. above the main line so as to prevent drain
back-flow.
④ In case of 凹凸 part or a vertical pipe, be sure
to install a drain valve at the lower part.

Valve

Compressor Main Air

D i V
Drain Valve
l
Discharge Line Line

Matters to Be Attended to
™ Conduct piping work lest drain flow back from
the discharge line.

25
3. How to Install change & innovation

3-4. Notice for Piping

(4-2) Directions for Piping Work When
• In the case of shift operation equipment, close
Using Parallel completely a stop valve in the discharge line of
equipment at a stop. Also, in the case of automatic
shift equipment, replace the stop valve with an
automatic valve such as an electric valve so that the
automatic valve may be shut while the compressor is
at a stop.

Matters to Be Attended to
In the event that one is operating and the other is at a
stop as in the picture, if the stop valve in the discharge
line of a compressor at a stop is opened, a back flow
occurs at a after cooler and a minimum pressure valve
in the compressor at a stop, which causes the rust of
the after cooler and the minimum pressure valve.

(4-3) Air Tank

! Attention

In the event of operating without installing an air tank,

the frequency of load and unload increases, which
lowers machine life remarkably.

26
3. How to Install change & innovation

35 N
3-5. Notice
ti ffor Wi
Wiring
i
● All compressor shall be wiring and ground with a power supply. Supply electric power voltage shall be keep
within ±3% of phase and within ±10% of rated voltage.

[ Notice ]

● Engineer and customer shall be install ground fault circuit in a compressor electric power wiring in
order to protect of short-term circuit. Engineer and customer shall be use appointed circuit to electric
power supply. So it is cause of accident of electric shock or fire and so on if capacity of electric power
circuit has not enough and electric work has not do.
● Engineer and customer shall be bury an earth bar in the ground directly. And engineer and customer
shall not be connect in existing heavy iron structure or gas piping, water piping.
● Wiring no hang or step outward a cable.

● Wiring of inner compressor is completed.

● Carry out incoming power connection and grounding connection only.
● Screw a bolt tightly. It can be generate heat in the connecting part of overload relay if tie loosely.
● Carry out safety check-out and all power cut when it check a power panel and maintenance of
a compressor, fueling.

▣ An Example of Main Power Wiring (a distributing circuit breaker is bilt into a circuit breaker.)

Main Power
Supply Line

Connected to
Compressor

! Attention

™ At the main power, be sure to place a distributing circuit breaker. Only with a circuit breaker such as a
knife switch, the compressor can not be protected and may be damage by a fire in the event of a
short-cut
short cut accident,
accident etc.
etc
™ Be sure to conduct earthing from the compressor. Without earthing, an electric shock accident or the
disorder of the compressor may be caused. Using as the earth a steel frame other than a building also
may cause malfunction. Be sure to earth into the ground separately.

27
4. How to Operate change & innovation

4-1. Test Run of Compressor

(1) Test run prepare and maintenance

① Customer shall be test run so compressor isn’t operate beyond 1 weekend or a period after install.
[ Notice ]
● Wire and piping before power turn on and check for installation state.
● Keep a voltage within specified value scope and put to earth.

② Check-out oil level of a compressor.

Keep beyond oil level gauge between upper and center of lower
of a compressor oil level.
Full oil beyond center in the lower from oil level gauge of oil.

[ Notice ]
Use recommendation oil of Donghwa pneutec.

● Use recommendation oil below next.

● Another brand oil is sticky if oil mix, it is cause of adhesive property rise.
If worstt condition,
diti a compressor air
i end
d can be
b cause off trouble
t bl or no operate.
t
Also that air end repair needs expensive cost.
Therefore no mix another brand oil and avoid.
Clean inner air end completely if a compressor oil change the current oil.
In that case contact with Donghwa Pneutec or agency.

< Recommended Lub. Oil For Air Compressor >

Donghwa Pneutec Nex Komp’ Oil

28
4. How to Operate change & innovation

4-1
4 1. Test Run of Compressor

③ Check a tension of V-Belt in case V-Belt pulley type.

④ Open a stop valve of air receiver tank and stop valve of a compressor discharge side.

⑤ Check-out 0 bar of pressure gauge.

⑥ Check-out that rotation direction of pulley or belt equal to direction of machine.

If rotation direction is reverse, engineer and customer shall be check-out a rotation direction
and main power cut and change wire of 2phase in the middle of 3phase.

Terminal

Change the connection of

2 lines among 3 lines
each other.

[ Caution ]

● Micom Panel can be damage a LCD when it exposure to direct rays of the sun.
In case it can not be quality guaranteed.

29
4. How to Operate change & innovation

4-1. Test Run of Compressor

(2) Test Rum

1) Check-out the power of micom panel after main power connection.

2) Check the inner pressure 0 bar of oil tank.

3) Push a start button of micom panel.

4) Checking increase the discharge air pressure gradually.

(3) During Test Run

1) Proper a temperature and pressure during operate.

2) Check-out pressure of full-load return and unload of discharge pressure gauge.

3) Check a leak of air and oil and so on.

4) Check-out a compressor state of noise, vibration and so on.

5) Check-out operation state from the micom panel of discharge pressure and temperature
during operating.
Micom panel set below next setting values in the micom panel display generally

Setting Discharge Pressure

7.0 bar 8.0 bar 9.0 bar

Loading/Unloading Operation 6~7 bar 7~8 bar 8~9 bar

Operation Temp’ of Cooling Fan STOP : 75℃ / START : 85 ℃

Setting Pressure of Safety Valve 7.5 bar 8.5 bar 9.5 bar

Air High Temp’ Setting Alarm : 100℃ / Trip : 110℃

※ In case of modulating of working pressure, contact with Donhwa Pneutec’s head office.

30
4. How to Operate change & innovation

4-1. Test Run of Compressor

[ Notice ]
● Engineer and customer shall not be take a face and hand of safety valve of discharge side a nearby.
It is danger because of compressed air discharge of high pressure.

(4) Stop

1) If a compressor is stop, a compressor stop after 60 second(Stop after unloading operation).

2) If a emergency stop button, a compressor stop just.

3) Check
Ch k a pressure 0 b
bar after
ft a compressor stop.
t

4) Check an oil gauge of oil separator.

5) Close a stop valve when a compressor is stop.

6) Check the inner pressure 0 bar of oil tank when re-start after stop or emergency stop

7) Shut down the power after a compressor stop.

[ Notice ]

● The Compressor have finished a performance test from the Donghwa Pneutec so don’t
don t prohibit
a random or arbitrary operate and disassembly regarding components.

31
4. How to Operate change & innovation

4-2. Daily Operation

4-2-1 Check before operation
4-2-1.

(1) Check-out of a compressor oil level gauge

[ Caution ]
● Don’t touch in the blush part or rotation of compressor while open door.
Engineer and customer can be seriously injured.

● Check-out oil level of a compressor.

Keep beyond oil level gauge between upper and center of lower
of a compressor oil level.
Full oil beyond center in the lower from oil level gauge of oil.
※ Oil shall be use a NEX Komp’ Oil of Donghwa Pneutic.

[ Notice ]
● Wire and piping before power turn on and check-out for installation state.
● Keep a voltage within specified value scope and put to earth
earth.

(2) Check-out the air filter of suction side and clean.

● Clean dust and dirty things by clean air from separate a compressor if dust remain in the air filter
filter,
check-out a dust in air filter. If no cleaning, clean use a detergent.
Change the air filter reasonable period according to state after clean.
And change the air filter in case of damage terribly.

(3) Open the stop valve of air tank and a compressor discharge part.
(4) Check-out that rotation direction of pulley or belt equal to direction of machine.
If rotation direction is reverse, engineer and customer shall be check-out a rotation direction
and main power cut and change wire of 2phase in the middle of 3phase.
[ Caution ]

● Micom Panel can be damage a LCD when it exposure to direct rays of the sun.
In case it can not be quality guaranteed.

32
4. How to Operate change & innovation

4-2. Daily Operation

4-2-2. Operation
1) Check-out the power of micom panel after main power connection.

2) Check the inner pressure 0 bar of oil tank.

3) Push a start button of micom panel.

4) Checking increase the discharge air pressure gradually.

4-2-3. During Operation

1) Proper a temperature and pressure during operate.

2) Check-out pressure of full-load return and unload of discharge pressure gauge.

3) Check a leak of air and oil and so on.

4) Check-out a compressor state of noise, vibration and so on.

5) Check-out operation state from the micom panel of discharge pressure and temperature
during operating.
Micom panel set below next setting values in the micom panel display generally

Setting Discharge Pressure

7.0 bar 8.0 bar 9.0 bar

Loading/Unloading Operation 6~7 bar 7~8 bar 8~9 bar

Operation Temp’ of Cooling Fan STOP : 75℃ / START : 85 ℃

Setting Pressure of Safety Valve 7.5 bar 8.5 bar 9.5 bar

Air High Temp’ Setting Alarm : 100℃ / Trip : 110℃

※ In case of modulating of working pressure, contact with Donhwa Pneutec’s head office.

33
4. How to Operate change & innovation

4-2. Daily Operation

[ Notice ]
● Engineer and customer shall not be take a face and hand of safety valve of discharge side a nearby.
It is danger because of compressed air discharge of high pressure.

4-2-4. Stop

1) If a compressor is stop, a compressor stop after 60 second(Stop after unloading operation).

2) If a emergency stop button, a compressor stop just.

3) Check
Ch k a pressure 0 b
bar after
ft a compressor stop.
t

4) Check an oil gauge of oil separator.

5) Close a stop valve when a compressor is stop.

6) Check the inner pressure 0 bar of oil tank when re-start after stop or emergency stop

7) Shut down the power after a compressor stop.

[ Notice ]

● The Compressor have finished a performance test from the Donghwa Pneutec so don’t
don t prohibit
a random or arbitrary operate and disassembly regarding components.

34
4. How to Operate change & innovation

4-2. Daily Operation

4-2-5 Piping & Instrument Diagram
4-2-5.

35
4-2-6. Sequence Diagram
4. How to Operate change & innovation

4-2-7. Capacity Control Block Diagram

Starting Unloading Operation Loading Operation Stop

Resetted

System Pressure 0 Amount of compressed air Amount of compressed air STOP Button ON
㎏f/㎠ used decreases used increases

Solenoid Valve OFF

Rising to the max. pressure Decreasing to min.
START Button ON pressure

Suction valve closed

Motor full voltage
Pressure switch contact Solenoid Valve ON
Y-△Starting converted
Solenoid valve open
p and
discharge internal
Suction valve opened
pressure.
Solenoid Valve ON Solenoid Valve OFF

Loading operation starts

Magnet contact resetted
Suction Valve Opened Suction valve closed

Motor stops
Loading Operation Unloading Operation Pressure rises

Solenoid valve open and

START Lamp OFF
Loading Operation
discharge internal pressure

Decreasing up to the
min. pressure

37
4. How to Operate change & innovation

4-3. Control System

(1) Compressor air system

● Suction air is inhale to compressor air end through suction piping and air filter, unloader. Heated
air is cooling 45℃ to transfer air cooler approximately and compress until 7.0~9.0 bar in air end.
Cooled air is supply to work place through discharge piping.

(2) Lubricant System

● Oil is transfer to oil cooler pass strainer by oil pump of gear case lower part.
Cooled oil in oil cooler is lubricative to compressor bearing, timing gear, a multiplying gear and circulate
along the cartridge type oil filter.
Used lubricating oil is circulate and return in oil tank(gear case).

38
5. Check and Maintenance change & innovation

5-1. Periodical Maintenance of Compressor & Notice after

Maintenance
This manual provided a basic periodical check-out and maintenance period for need a normal operation of a
compressor. Engineer and customer shall be frequently check-out and maintenance of a compressor in case
operating during state in poor a compressor condition.

[ Caution ]

● Hang up the mark “Check-out and Maintenance” put up a notice in a conspicuous place and shut off
all power before check-out.
If compressor turn on the power during check-out and maintenance mistakenly, a compressor can be
occur electric shock accident as well as fire through short-circuit.

[ Notice ]

● Engineer and customer shall be change a oil every once a 2000 hr and twice a 1 year.
But if a oil was pollute terribly, oil shall be change quickly.
Provided that, a oil change period can be change according to operation environment condition.
● Don
Don’tt act that oil mix with another brand oil
oil, a oil can be fall a quality
quality.
Please change with oil filter.

[ Notice ]

● Use a recommended oil and grease surely.

● Use a articles of the best quality.
● Don’t assembly & disassembly a component like motor and a compressor air end.
If engineer and customer is need a assembly & disassembly, contact with agency nearby.
● Don’t put a compressor on electric component at a short distance water or steam.
C i &d
Caution danger to electric-short
l i h and d fifire.
● Don’t apply a transform on a compressor without pre-approval.
● Guarantee is except from as follows a problem that specified an article or material isn’t use on
a compressor or immatureness through user.

39
5. Check and Maintenance change & innovation

5-1. Periodical Maintenance of Compressor & Notice after

Maintenance
1) Use proper a tools in the check-out and maintenance work.
2) Engineer and customer can be accident unsuspected during work if user use improper tools.
3) Vent a oil before work starting in case expectation that a large oil flow out from compressor during
disassemble a compressor and cleaning.
4) P
Putt empty
t container
t i on b
bottom
tt off compressor oilil portt so residue
id oilil flflow outt tto b
bottom
tt or inner
i a
compressor
5) Don’t vent a residue oil toward land, river, lake and so on.
This is cause of environmental pollution.
Engineer and customer can be punish in case vent a oil, all sorts of solution, filter without permission
toward land, river, lake
6) Clean a compressor room so as not to remain a dust or residue oil after maintenance work.
7) Change a new alarm name plate in case damage or fall.
Keep to clean state so as to see a eye of nameplate contents.

40
5. Check and Maintenance change & innovation

5-2. Daily Check & Operation Record

1) Carry out check-out every morning and daily before operation.
2) Observe the following in detail during daily check-out or test, maintenance work.
Solve and examine a cause and effect immediately if problem is discover.
Contact with agency nearby if problem was occur or if it not showed in the manual or if problem was
occur in parts.
p

a) Check a control and gauge during operation

b) Check a oil lever, leak, pollution
c) Check the exterior, abnormal noise and over heat
d) Check a loose screws and bolts
bolts, nuts
e) Check a damage, corrosion, miss of parts
f) Check a operation state of each parts
g) Check a tension of V-belt

3) Engineer and customer can be discover a problem of a compressor quickly, if user was record each parts
check-out result continuously. Then, it can be a rapid action.
Record a information of a compressor operating time, discharge pressure, oil level
through make out a maintenance schedule efficiently and look into a change of each parts at a glance.
Engineer and customer is a help to a record with information and oil supplement period, maintenance item.

41
5. Check and Maintenance change & innovation

5-2. Daily Check & Operation Record

(1) Daily operating control

① Do a daily control that user is record every operating state in the daily record of compressor.
② Carry out a maintenance when it exceed control value.

(2) Periodical check-out

① Carry out periodically a check-out and maintenance according to a compressor maintenance standard.
② Comply a maintenance standard in the normal operating condition and maintain a maintenance standard
time in half shorten in place poor operating condition.
③ Maintenance standard isn’t a guarantee period.
④ Change a problem parts during check-out.
⑤ Prevent a maintenance and carry out a periodical check-out once a year at least.
⑥ Use the Donghwa Pneutec’s articles of the best quality about changing parts surely.

(3) Overhaul
① Carry out total maintenance of compressor per 5 year.
② Change a bearing of air end and motor during total maintenance.
Change of a bearing of air end and motor needs to a detail assembly, Donghwa Pneutec’s engineer of
head quarter can be only change. It is cause of a compressor damage in case repair of unqualified
engineer.
i

42
5. Check and Maintenance change & innovation

5-3. Standards & List for Compressor Maintenance

Compressor
p Periodical check-out
◎ : Clean ○ : Check ● : Change

Maintenance Check Hours

Checking Knack 1000 h 2000 h 4000 h 20000h

Checking Item Remarks
· Measures Taken Daily
3 months 6 months 1 year 5 year

Oil Level Check ○ Replenish if insufficient

Compressor Temp. Check ○

Check pressure difference

Oil Separator Element
between compressor and ○
(Differential Pressure)
air tank

Electric Starter and Wiring Check deterioration. ○ Change deteriorated part.

Electric Starter Bolt, Pipe

Check, Refastening ○
Connecting Part

Safety Valve Check operating conditions. ○ Change if abnormal

Cleaning inside Starting Board Clean with dry air. ◎

Oil Return Line Check, Cleaning ◎

Oil & After Cooler Cleaning ◎

Cooling Fan Cleaning ◎

Oil Change ○ ●

Change after initial 500 h

Oil Filter Element Change ●
(1month).

Change after 3,000h

Air Filter Element Cleaning and Change ◎ ●
(9 months).
Ch
Change after
ft 3,000h
3 000h
Separator Element Change ●
(9 months).

Suction Valve Check operating conditions. ○ Change if abnormal.

Min. Pressure Valve Check operating conditions. ○ Change if abnormal.

Belt Check abrasion. ○ ○ Change if abnormal.

High-pressure Hose, Tube Check hardening. ● Change after 8,000h (2 years).

O-ring and Gaskets Check oil leak. ● Change after 8,000h (2 years).

AirEnd Bearing & Oil Seal Check joint & oil leak. ● Change after 30,000h.

Motor Bearing Check joint. ●

① If surrounding environment is poor due to dust

dust, temperature
temperature, humidity,
humidity etc
etc., reduce the periods by half
half.
② Conduct check & maintenance at a point of time reached earlier between operating hours and operating years.
③ As to the check & maintenance of parts, entrust them to your place of purchase or DONGHWA PNEUTEC’s head office.
(Cause of a serious accident)

43
5. Check and Maintenance change & innovation

5-4. Know-how of Check & Maintenance

■ Motor grease supply

Grease shall be a supply during operating.

(Supply procedure)
① Open a grease exhaust port.
② Supply a grease through a grease supply port using grease gun
gun.
③ Stop a grease supply if new grease is flow out to grease exhaust port.
④ Close a cover of grease exhaust port.

■ Change of Oil Filter Element

Oil filter filter out the iron contents and carbon from oil, and supply clean oil to air end.
When 500 hours (1 month) passes after the test run of a compressor, change an oil filter element.
After then, change oil every 2,000 hours (6 months).
Shut off the power, and check whether pressure inside the compressor is 0 ㎏f/㎠.

■ Change of Air Filter Element

The air filter filter out dust, iron, motes, wood chips, flocks, etc. during air suction, and prevent the burning
g of a compressor.
damage p .
Clean it every 1,000 hours (3 months).
For cleaning, separate the air filter element, and blow high-pressure dry air from the inside toward the outside.
Cleaning is possible up to twice; change it after 3,000 hours (6 months.).
In case of cleaning or change, wipe the air filter housing or the entrance of the suction valve with a clean
cloth.
If the air filter housing has a dust bag, push it lengthwise to remove dust.

■ Check-out of tube and rubber hose

Check-out the tube a damage and crack excessively.

Engineer and customer contact with an agency nearby in case tube change.
Check-out the tube a damage
g and crack between oil p
pump
p and rubber hose in suction p
part of oil cooler
Contact with an agency nearby in case rubber hose change.

44
5. Check and Maintenance change & innovation

5-4. Know-how of Check & Maintenance

■ Cleaning of Oil & Air Cooler
Shut off the power; check the contamination degree of cooler fin. Clean it, if necessary.
Blow compressed air from the cooling air exit side toward the suction side.
When a cooler was contaminated by oil stain, etc., separate it from a compressor, and clean it with a
washing solvent, etc.
Operation under contaminated condition cause of the over-temperature of a compressor.

■ Cleaning of Cooling Fan

Check whether oil stain or dust has adhered to a cooling fan. If necessary, remove by means of high-pressure
dry air.
Operation with foreign substances may cause of vibration, the burning damage of a fan motor, and so on.

■ Supplement and Change of Oil

Oil is perform a role cooling of oil cooler, bearing lubrication and rotor of air end of a compressor.
Check every day the condition of oil, and whether the amount of oil is within the normal range.
Replenish within the prescribed time of change, when oil amount is less than the prescribed range.
In addition,
addition in case of replenishment within the time,
time there may be influences such as over-temperature
over temperature,
poor minimum pressure maintenance, etc. Check them and take necessary measures.
When changing oil, used oil shall be drained completely.
Shut off the power, and check whether pressure inside a compressor is at 0 kgf/㎠.
Open the drain valve, and drain completely a oil inside the tank to a waste oil receptacle. After operation,
oil is hot; beware of a burn.
Shut the drain valve; open the oil supply hole; and fill the recommended oil from DONGHWA PNEUTEC
up to the maximum on the oil gauge.
Close the oil supply hole; make a test run; and check the oil gauge to see whether it is within the normal
range.

▣ Oil Recommend

Donghwa Pneutec Nex Komp’ Oil

45
5. Check and Maintenance change & innovation

5-4. Know-how of Check & Maintenance

■ Check-out of check valve
Check-out the check valve so compressed air from check valve isn’t leak when full-load and unload is repeat
frequently and so compressed air from check valve is a little leak.
Open the service valve in order to vent a compressed air from air end of a compressor and stop valve is stop
of main discharge piping
piping.
Remove the piping of discharge of aftercooler.
Contact with Donghwa Pneutec’s head quarter or agency in order to check-out.

■ Cleaning of Starting Board Panel and Check of Part Fastening

Shut off the power, and remove dust, etc. by means of high-pressure dry air.
Check the connection state of wiring or parts. Check whether there is a deteriorated part or wire;
and change a necessary part.
Dust, etc. may cause of the malfunction of parts, burning damage, or a fire.

■ Change of Separator Element

The separator element separates air and oil in a state of mist; absorbs oil and sent it to the air end; and
sends the minimum oil contents and compressed air to the discharge line.
When 3,000 hours (6 months) passes after the compressor starts, change the separator element.
Shut off the power; and check whether pressure inside the compressor is at 0 kgf/㎠.
Disassemble the return line and the control piping connected to the separator tank cover and the min.
pressure valve; and detach the bolt of the cover.
Open the cover; remove a gasket (O-ring); and then detach the separator element.
After disassembling, check the inside of the tank, and remove impurities.
Check the condition of O-ring at the top of the separator tank.
Put in a new separator element, and assemble in the reverse order of disassembling.
D i assembling,
During bli check
h k whether
h th ththe return
t li lilies correctly
line tl att the
th llower partt off the
th element.
l t

46
5. Check and Maintenance change & innovation

5-4. Know-how of Check & Maintenance

■ Adjustment and Change of V-belt

Check whether V-belt tension is suitable with the table below.
When tension is small, adjust tension. If a belt is loose, slip
occurs, which causes breakage or abnormal sound.
Adjustment Below 1mm
When tension is great, adjust tension. Too great tension causes
the life-shortening of a motor and a bearing of the compressor,
and the severance of an axis.
Check whether the V-shaped grooves of a compressor pulley is
aligned with that of a motor pulley.
Tension Adjustment
j Bolt

※ Adjustment of Belt Tension

Model Pressure (kgf/㎠) Initial Tension (N)

7~8 196
NeX-15
9 206
7 216
Tension Gauge Bending Value
NeX-22 8 235
9 245
7~8 196
NeX-30
9 206
7~8 255
NeX 37
NeX-37
9 265
NeX-45 7~9 226

※ Power Transfer Unit (Reference)

Model Power Transfer Unit

NeX-15~45A
NeX-15 45A Belt-Pulley Type
More than NeX-55A Direct Coupling Type

■ Long Suspension of Operation

If not using the compressor for a long time (1 month), run it once a week for more than 10 min. to
prevent rust.
p

47
5. Check and Maintenance change & innovation

5-5. Daily Maintenance Record Sheet

Discharge Sep.
Operating Power Pressure Discharge element Load
hours Temp. Oil Level
Voltage Current MAX MIN D. P. Factor
Abnormality &
Date of Hour V A ㎏f/㎠ ㎏f/㎠ ℃ ㎏f/㎠ % Measures Taken Remarks
Check MAX. -
≤ 7.5
Under (1.0~1.5)
-5~+10% ≤ 9.5 71~95 0.2~0.6
Rating ,4.5 or
of Rating ≤12.5
more

48
6. Causes of Troubles and Troubleshooting
change & innovation

No. Phenomenon Checking Cause Troubleshooting

When the compressor does not start

Is there excessive current consumption, too Check rated current, rated voltage, a
small rated voltage, or a drop in press.? drop in voltage.

Is the compressor operate over the a Reset input. Remove the cause of
regulation pressure? pressure increase.

Change
g wires of 2 p
phases among
g3
Is the compressor backlash?
phases.

Is there EOCR setting error or malfunction? Reset or change EOCR.

Is there residual pressure within inner

Make pressure inside the tank 0 kg f/㎠.
Main motor overload a compressor during starting?
1
lamp is ON.
Grasp the cause. Change separator
Is a separator element a contaminated?
element.
element

Is not an air end operate? Change the Air End.

Overhaul. Check the operating state of

Is an oil viscosity operate?
temperature control valve.

Is the main motor damaged? Repair or change the motor.

Is there damaged to a fan? Change fan.

fan

Is there damaged a fan motor? Change fan motor.

Improve surrounding environment to be

Is the ambient temperature high?
45℃ and below through ventilation.

Is a regulation pressure operate over? Readjust pressure.

Is a cooler contaminated? Clean cooler.

Discharge over-temp. Is a dust filter contaminated? Clean cooling air filter.

2
lamp is on.
Is an oil insufficient? Replenish with oil.

Is a separator element contaminated? Grasp cause. Change separator element.

Is an air end bearing damaged? Change bearing

bearing. Check oil line
line.
Is a state of temp. sensor damaged
Change temp. sensor.
poorly?
Is the capacity of distributing circuit breaker
Replace with rated capacity.
Distributing circuit insufficient?
3
breaker operates.
Is a short circuit occur? Grasp cause, and take measures.

Is the operation or contact of a magnetic

Change
contactor or a timer operate?
4 Others
Is the contact of start/stop switch operate? Change

49
6. Causes of Troubles and Troubleshooting
change & innovation

No. Phenomenon Checking Cause Troubleshooting

When the compressor is started

Check whether the change lamp is on.

Is an air suction filter contaminated?
Clean or Change.

Check the conditions of servo-cylinder,

Is the opening of a suction valve operate? solenoid valve, proportional control valve,
butterfly angle, etc., and take measures

Check its operating

g condition; take
Is not a solenoid valve operate?
Compressed Air is measures; or change.
insufficient.
1 Check its operating condition; take
Compression is not Is not a pressure sensor operate?
measures; or change.
made.
Is the contact of a magnetic contactor or a Check its operating condition; take
timer operate? measures; or change.

Check an air leak from piping; take

I air
Is i consumption
ti capacity
it much?
h?
measures; or install more.

Is a safety valve under the a regulation Check its operating condition; take
pressure operate? measures; or change.

Check the conditions of packing, servo-

Is the opening of suction valve operate cylinder, solenoid valve, proportional
poor? control valve, butterfly angle, etc., and
take measures.

Check operating condition; take

Is not a solenoid valve operate?
Abnormal pressure measures; or change.
2
rises.
Check operating condition; take
Is not the pressure sensor operate?
measures; or change.

Is not a compressed
p air of Check solenoid valve valve,, and take
discharge side vent during unloading? measures.

Is the control line injectionzed? Improve surrounding environment.

Is the oil recovery line contaminated? Clean strainer and recovery line.
Is a separator element damaged? Change separator element.
Is a oil line contaminated or deteriorated? Change oil and the oil filter element.
Is a regulation oil capacity charge over? Maintain the optimum amount of oil drain.
Oil is consumed much.
3 Oil is much in Check surrounding environment, cooler
Is the temperature of discharge air high?
discharge air. contamination, etc., and take measures.

Adjust the pressure to the min. pressure

Is pressure 4.5㎏f/㎠ operate and below?
4.5 kg f/㎠ or more.

Is not the min.

min pressure of min.
min pressure Check min
min. pressure valve
valve, and take
valve maintain? measures.

50
6. Causes of Troubles and Troubleshooting
change & innovation

No. Phenomenon Checking Cause Troubleshooting

When the compressor is started

Is the connection of a belt or coupling Check belt tension and connecting

between the motor and the air end poor? condition, and take measures.

Is the fastening state of the cover, parts,

Fasten again.
etc. operate?

Is there noise or vibration when main

Check rotating parts, and take measures.
Abnormal noise or motor Air End,
motor, End fan
fan, or fan motor rotate?
4 abnormal vibration
occurs. Is there a fastener for transportation
Remove fasteners.
/maintenance mounted?

Is not the surface of an installation floor Readjust position, or insert a rubber plate
level flat? into a gap.

Is the location of installation to a wall

Readjust position
position.
close?

51
7. Machine Long-term Storage change & innovation

( ) Preparing ffor long-term storage

(1)

When the compressor is stored for a long time without operation, read and follow the below.

● Location where is less dust, low temperature, low humidity, dry and well ventilated.
● Air intake is blocked with tapes or etc. to restrict dust or humidity.
● Measure insulation resistance of motor and check that it is over 1MΩ once in three months.
● Replace the stop position by turning the pulley or coupling to avoid rust formation at the bearing
once in three months.

(2) Treatment before shutdown

When the compressor is not operated for a long time, read and follow the below.

● Cut off power.

● Close
Cl stop
t valve
l att th
the outlet
tl t side,
id if applied.
li d
● Cover the entire machine with vinyl sheets.

(3) Treatment before re-operation

Check the follow items.

● Remove the vinyl sheets.

● Measure insulation resistance of motor and check that it is over 1MΩ.
● Check to turn the pulley or coupling smoothly
● Check the main power cable and the terminal.
● If any abnormal condition is sensed, immediately turn OFF the power and take a suitable action
according to the cause of trouble and remedy

52
8. Warranty change & innovation

Warranty
Product Type Model : NeF- / ㎏f/㎠ / V/ Hz
Serial No.
Date of Purchase

Date of Initial Use

Firm Name :
Place of
Address:
Purchase
Tel. : Fax :

In the event that any part of the compressor has gone wrong, within the period of guarantee below, due
to defective materials or defective manufacture, while normally used in accordance with the Operating
Manual, we repair it injection of charge. But, as to a case ruled out of guarantee, we will repair for a
consideration.

1. Period of Warranty : 1 year after the date of delivery

2. Cases Ruled Out of Guarantee

① When used at pressure exceeding the rated pressure (max. pressure)

② Consumable part to be changed periodically (filters, rubber products, bulbs, etc.)
③ Disorder caused byy neglectful
g change
g of consumables,, p
parts,, etc.
④ When used under severe environment (abnormal voltage, abnormal temperature, a dusty place, a
place of high humidity, etc.)
⑤ When remodeling voluntarily the product or its parts without DONGHWA PNEUTEC’s permission
⑥ Disorder caused by not conducting daily checks and periodical checks specified in the Operating
Manual
⑦ Insignificant strange sound,
sound vibration,
vibration etc.
etc regarded as having no influence on general quality or
performance
⑧ Disorder caused by a repair not done by DONGHWA PNEUTEC’s agency or head office, or by
use of parts other than genuine parts
⑨ Disorder caused by natural disaster

We do not guarantee secondary compensation such as production cost compensation, sales

compensation, etc. for the disorder or abnormality of this product.

53
DRAWING & PART LIST change & innovation

NeX 22A
NeX-22A
PART NO. ITEM NO. NAME OF PART SPECIFICATION QUANTITY

1 A601500101 AIR END CF75D8 1

2 A601500117 AIR END GASKET 116*116*φ65*3t 1

3 A602201212 AIR END PULLEY 30A7(16PK Ø115)2012*Ø45m6 1

4 A406302501 AIR SUCTION FILTER CASE (BODY,CAP,CLAMP) 1

5 A406302502 AIR SUCTION FILTER ELEMENT(65) Ø185*133L 1

6 A602200125 AIR SUCTION VALVE AIV50B-S 1

7 A602200601 COOLER 22kW (665*600*65t) 1

8 A602200603 COOLING FAN DR-DT1212(440V,3PH,60HZ,6P) 1

9 A601501029 DUST FILTER 325*320*5t 2

10 G090630265 FLEX.HOSE 10K-40A-600*220L(AIR END→OIL TANK) 1

11 G090630266 FLEX.HOSE 10K-20A-235*225L(MIN.PRESS.V/V→COOLER) 1

12 G090630267 FLEX.HOSE 10K-20A-950L (FILTER → COOLER) 1

13 G090630268 FLEX.HOSE 10K-20A-1350L (COOLER → AIR END) 1

14 G090630256 FLEX.HOSE 10K-8A-1140L (OIL FILTER→END BEARING) 1

15 G090630257 FLEX.HOSE 10K-8A-1050*30L (OIL TANK→INTAKE V/V, OIL TANK→AIR END) 2

16 G090630258 FLEX.HOSE 10K-8A-300L (INTAKE V/V→ AIR) 1

17 A800200103 FLEX.MOUNTING VNM-A-50 6

18 A601500801 MICOM PANEL NDA320D 1

19 A602200807 MIN. PRESSURE VALVE MPV25 1

20 A602201211 MOTOR PULLEY 30M(16PK Ø300)2517*Ø55m6 1

21 A602200418 OIL FILTER φ94*170L (30HP) 1

22 A602200403 OIL SEPARATOR ELEMENT φ200*φ168*230L (30HP) 1

23 A603700404 OIL SEPARATOR GASKET φ201*φ170*3t 2

24 A601500804 PRESSURE SENSOR 501.931003171 (DP520D) 2

25 A602201214 PULLEY BELT 16PK*1390mm 1

26 A800402003 SAFETY VALVE 7.5K-20A/25A 1

27 A601500805 TEMPERATURE SENSOR R T D 50L*5M

R.T.D 1

54
DRAWING & PART LIST change & innovation

NeX 37A
NeX-37A
PART NO. ITEM NO. NAME OF PART SPECIFICATION QUANTITY

1 A603700101 AIR END CF90D4 1

2 A603700118 AIR END GASKET 125*125*φ80*3t 1

3 A603701212 AIR END PULLEY 50A7(16PL Ø125)2012*Ø50m6 1

4 A406302501 AIR SUCTION FILTER CASE (BODY,CAP,CLAMP) 1

5 A406302502 AIR SUCTION FILTER ELEMENT(65) Ø185*133L 1

6 A603700125 AIR SUCTION VALVE AIV65C-S 1

7 A603700601 COOLER 37kW (780*696*100t) 1

8 A603700603 COOLING FAN DR-HT1512 1

9 A603701029 DUST FILTER 415*320*5t 2

10 G090630265 FLEX.HOSE 10K-50A-695*285L (AIR END→OIL TANK) 1

11 G090630266 FLEX.HOSE 10K-32A-265*135L (MIN.PRESS.V/V→COOLER) 1

12 G090630267 FLEX.HOSE 10K-20A-1030L (FILTER → COOLER) 1

13 G090630268 FLEX.HOSE 10K-20A-1460L (COOLER → AIR END) 1

14 G090630256 FLEX.HOSE 10K-8A-1140L (OIL FILTER→END BEARING) 1

15 G090630257 FLEX.HOSE 10K-8A-1050*30L (OIL TANK→INTAKE V/V, OIL TANK→AIR END) 2

16 G090630258 FLEX.HOSE 10K-8A-300L (INTAKE V/V→ AIR) 1

17 A800200103 FLEX.MOUNTING VNM-A-50 6

18 A601500801 MICOM PANEL NDA320D 1

19 A603700807 MIN. PRESSURE VALVE MPV32 1

20 A603701211 MOTOR PULLEY 50M(16PL Ø300)3020*Ø60m6 1

21 A603700418 OIL FILTER φ94*210L (50HP) 1

22 A603700403 OIL SEPARATOR ELEMENT φ200*φ168*305L (50HP) 1

23 A603700404 OIL SEPARATOR GASKET φ201*φ170*3t 2

24 A601500804 PRESSURE SENSOR 501.931003171 (DP520D) 2

25 A603701214 PULLEY BELT 16PL*1400mm 1

26 A800402003 SAFETY VALVE 7.5K-20A/25A 1

27 A601500805 TEMPERATURE SENSOR R T D 50L*5M

R.T.D 1

55
ˆBeyond air compressor˜
change & innovation

OFFICE & 1589-1, SONGJUNG-DONG, KANGSEO-KU,

PUSAN, REPUBLIC OF KOREA
FACTORY
TEL. +82-51-974-4800
FAX. +82-51-974-4810

http://www.dhkomp.co.kr
HOME PAGE

infocomp@dhkomp.co.kr
E-MAIL

54