FScurtis NxB/V Series User manual

CAP-834
MAY, 2018
Rev. E
WARNING
Personal injury and/or equipment damage will be result by failing to pay attention to the vital safety information and instructions
in this manual. Carefully read, understand, and retain all safety information and instructions before operating this compressor.
NxB/V Series
OIL-INJECTED ROTARY SCREW COMPRESSORS
Operator Manual
4 –15 kW

CAP-834 3
Information on these operating instructions
These instructions enable you to use the machine
safely and efficiently. The instructions are a compo-
nent part of the machine and must be accessible for
staff at all times.
Staff must have carefully read and understood
these instructions before starting all work. The basic
prerequisite for safe working is compliance with all
the safety instructions and instruction for actions
included in these operating instructions.
The local occupational health and safety regulations
and general safety rules for operational area of the
machine also apply.
The instructions for the machine do not cover op-
eration of the controller. Therefore, the instructions
and content of the instructions for the controller in
question must also be taken into account.
Copyright
These instructions are protected by copyright and
for internal purposes only.
These instructions must not be made available to
third parties, reproduced in any way -
even excerpts - and the content must not be uti-
lized and/or communicated, except for internal pur-
poses, without the written permission of the manu-
facturer.
Any infringement shall be subject to compensation
for damages. We reserve the right to assert further
claims.
Limitation of liability
All information and instructions in this manual have
been compiled taking account of the applicable
standards and regulations, state-of-the-art technol-
ogy and our years of knowledge and experience.
The manufacturer assumes no liability for damages
caused by:
◼ failure to adhere to these instructions
◼ improper use
◼ use of unqualified staff
◼ unauthorized conversions
◼ technical modifications
◼ use of non-approved spare parts
The actual scope of supply may differ from the de-
scriptions and illustrations in these instructions in
the case of special designs, the inclusion of addi-
tional ordering options or as a result of the latest
technical modifications.
The obligations agreed in the contract of supply, the
manufacturer's general terms and conditions of
business and delivery and the legal regulations
valid at the time of completion of the contract apply.
Customer service
Our Customer Service department is available to
provide technical information.
In addition, our employees are always interested in
receiving new information and hearing of your expe-
riences from usage which could be valuable for the
improvement of our products.

Table of contents
CAP-834
4
1Design and function...............................................................................................................................7
1.1 Overview ........................................................................................................................................ 7
1.2 Brief description .............................................................................................................................. 9
1.3 Assembly description ..................................................................................................................... 9
1.3.1 Controller ................................................................................................................................... 9
1.3.2 Enclosure panels ....................................................................................................................... 9
1.3.3 Drive unit ................................................................................................................................... 9
1.3.4 Intake filter ...............................................................................................................................10
1.3.5 Compressor airend ..................................................................................................................10
1.3.6 Oil separator tank ....................................................................................................................11
1.3.7 Air/oil separator .......................................................................................................................11
1.3.8 Minimum pressure and non-return valve ................................................................................11
1.3.9 Coolers ....................................................................................................................................12
1.3.10 Oil filter ....................................................................................................................................12
1.3.11 Cooling air fan .........................................................................................................................12
1.3.12 Refrigeration dryer ..................................................................................................................13
1.4 Interfaces ......................................................................................................................................13
2Safety.....................................................................................................................................................14
2.1 Symbols in these instructions .......................................................................................................14
2.2 Proper use ....................................................................................................................................15
2.3 General safety ..............................................................................................................................16
2.4 Safety devices ..............................................................................................................................16
2.4.1 Position of the safety devices .................................................................................................16
2.4.2 Description of the installed safety devices ..............................................................................17
2.5 Environmental protection .............................................................................................................17
2.6 Instructions on the machine .........................................................................................................18
3Technical data.......................................................................................................................................20
3.1 Serial tag ......................................................................................................................................20
3.2 General specifications ..................................................................................................................21
3.2.1 Operating conditions ...............................................................................................................21
3.2.2 Oil ............................................................................................................................................21
3.2.3 Consumables ..........................................................................................................................21
4Transportation, packaging and storage.............................................................................................22
4.1 Safety instructions for transportation ............................................................................................22
4.2 Inspection on receipt of delivery ...................................................................................................22
4.3 Packaging .....................................................................................................................................22
4.4 Symbols on the packaging ...........................................................................................................22
4.5 Transportation ..............................................................................................................................23

Table of contents
CAP-834 5
4.6 Storage ......................................................................................................................................... 23
5Installation and commissioning .........................................................................................................24
5.1 Safety instructions for the installation and commissioning .......................................................... 24
5.2 Requirements in the installation location ..................................................................................... 25
5.3 Installation .................................................................................................................................... 25
5.3.1 Remove shipping spacers ...................................................................................................... 25
5.3.2 Ventilation ............................................................................................................................... 25
5.3.3 Connection to the compressed air network ............................................................................ 26
5.3.4 Connecting to the power supply ............................................................................................. 27
5.4 Checking the oil level ................................................................................................................... 28
5.5 Start-up lubrication of the compressor airend .............................................................................. 28
5.6 Switching on after installation ...................................................................................................... 29
5.7 Work after the initial commissioning ............................................................................................ 29
5.8 Setting parameters ....................................................................................................................... 30
6Operation ..............................................................................................................................................31
6.1 Safety instructions for operation .................................................................................................. 31
6.2 Controller ...................................................................................................................................... 31
7Maintenance..........................................................................................................................................32
7.1 Safety instructions for maintenance ............................................................................................. 32
7.2 Spare parts ................................................................................................................................... 34
7.3 Maintenance schedule ................................................................................................................. 34
7.4 Maintenance work ........................................................................................................................ 36
7.4.1 Checking for leaks .................................................................................................................. 37
7.4.2 Checking the electrical connections ....................................................................................... 37
7.4.3 Checking the oil level/topping up the oil ................................................................................. 37
7.4.4 Checking the build-up of condensation .................................................................................. 38
7.4.5 Checking the compressor temperature................................................................................... 39
7.4.6 Inspect/clean coolers .............................................................................................................. 39
7.4.7 Checking the drive unit ........................................................................................................... 40
7.4.8 Replacing the oil/changing the oil filter ................................................................................... 40
7.4.9 Replacing the air/oil separator ................................................................................................ 41
7.4.10 Replacing the intake filter ....................................................................................................... 42
7.5 Measures after maintenance has been performed ...................................................................... 43
8Faults.....................................................................................................................................................44
8.1 Safety instructions for fault clearance .......................................................................................... 44
8.2 Fault displays ............................................................................................................................... 45
8.3 Fault table .................................................................................................................................... 46
8.4 Work for fault clearance ............................................................................................................... 48

Table of contents
CAP-834
6
8.5 Commissioning after remedied fault .............................................................................................48
9Index ......................................................................................................................................................49
10 Appendix ...............................................................................................................................................51
10.1 Bolt tightening torque requirements .............................................................................................51

Design and function
CAP-834 7
1 Design and function
1.1 Overview
Screw compressor
Fig. 1: Standard screw compressor with belt drive 3 - 15 kW)
1
Controller
2
Emergency stop button
3
Electrical cabinet
4
Enclosure panels
This chapter shows the screw compressors described in these instructions. They mainly differ in their construc-
tion, with or without receiver, and with the attachment of an additional section in which the refrigeration dryer and
the frequency converter are installed. However, their basic construction is the same.

Design and function
CAP-834
8
Components
The basic construction is the same for all screw compressor variants. The position or look of the
assemblies may vary from the illustration
Fig. 2: Overview of the assemblies: Screw compressor with frequency converter, refrigeration dryer (optional) and air receiver
(optional)
1
Pressure gauge
2
Refrigeration dryer (optional)
3
Air receiver (optional)
4
Discharge port
5
Frequency converter (optional)
6
Air/oil separator
7
Electrical cabinet
8
Safety valve (second safety valve on tank for the
option with compressed air tank, positioned
behind the pressure gauge)
9
Compressor airend
10
Separator tank
11
Power connection
12
Drive unit
13
Minimum pressure and non-return valve
14
Intake filter
15
Thermostat valve
16
Oil cooler
17
Air after-cooler

Design and function
CAP-834 9
1.2 Brief description
The fresh air supplied by the cooling air fan is fil-
tered through the intake filter. The air flows through
the intake valve into the compressor airend, where it
is compressed together with the injected oil to the
final pressure. The oil is largely separated from the
compressed air in the oil separator tank. The air/oil
separator removes the remaining oil from the com-
pressed air. The compressed air then flows through
the minimum pressure and non-return valve into the
air after-cooler and is cooled down before it leaves
the screw compressor via the discharge port.
The oil is separated from the compressed air in the
oil separator tank and the air/oil separator and flows
to the oil cooler. The oil temperature thermostat
adds the cooled oil to the hot oil via the oil cooler
bypass according to the set point temperature. Fi-
nally, the oil filter cleans the oil before it is injected
into the compressor airend again.
1.3 Assembly description
1.3.1 Controller
Controller variants
For detailed information about the
controller installed, consult the
separate  Controller documentation.
1.3.2 Enclosure panels
Fig. 3: Enclosure panels
Only qualified personnel may remove the enclosure
doors (Fig. 3/1) with the included special wrench.
Enclosure doors are a part of the electric shock
protection and reduce the sound level emitted by
the unit.
1.3.3 Drive unit
Various drive units are installed in the screw com-
pressors. They differ in construction, their technical
data and their functional principle as follows:
Screw compressor with V-belt drive
Fig. 4: Screw compressor with V-belt drive

Design and function
CAP-834
10
Screw compressor withV-belt drive and
frequency converter
Fig. 5: Screw compressors with V-belt drive and
frequency convertor
On the screw compressor with frequency converter
the electric motor is speed-controlled by the fre-
quency converter. Actuation is provided by a V-belt.
1.3.4 Intake filter
Fig. 6: Standard intake filter
The standard intake filter (Fig. 6/1) is fitted directly
on the compressor airend (Fig. 6/2).
1.3.5 Compressor airend
Fig. 7: Compressor airend
The air is compressed by the compressor airend
(Fig. 7/1) and fed to the oil separator tank (Fig. 7/2)
together with the injected oil. The compressor
airend and the oil separator tank are enclosed in the
same housing.

Design and function
CAP-834 11
1.3.6 Oil separator tank
Fig. 8: Oil separator tank
1
Oil separator
2
Sight glass
3
Filler nozzle
4
Oil drain
Fig. 9: Relief valve (1)
The compressor airend and the oil separator tank
(Fig. 8/1) are enclosed in the same housing.
The oil separator tank comprises several compo-
nents. The level of the oil can be read through the
inspection glass (Fig. 8/2). The oil is topped up via
the filler nozzle (Fig. 8/3) and removed via the oil
drain (Fig. 8/4).
1.3.7 Air/oil separator
Fig. 10: Air/oil separator
The air/oil separator (Fig. 10/1) removes the residu-
al oil from the compressed air.
1.3.8 Minimum pressure and non-
return valve
Fig. 11: Minimum pressure and non-return valve
The minimum pressure and non-return valve
(Fig. 11/1) does not open until the system pressure
has risen to 72 psi (5 bar). After switching off the
screw compressor the minimum pressure and non-
return valve prevents the compressed air from flow-
ing back out of the network.

Design and function
CAP-834
12
1.3.9 Coolers
Fig. 12: Coolers
The compressed air is cooled in the air after-cooler
(Fig. 12/1) before it leaves the screw compressor
via the discharge port (Fig. 12/1).
The oil is cooled by the oil cooler (Fig. 12/2) and fed
back into the oil circuit.
The plate (Fig. 12/3) can be removed for cleaning
the coolers.
1.3.10Oil filter
Fig. 13: Oil filter
The oil filter (Fig. 13/1) cleans the oil before it is
injected into the compressor airend once again.
1.3.11Cooling air fan
Fig. 14: Screw compressor with air receiver (optional),
refrigeration dryer (optional) and/or frequency converter
3–15 kWn
The cooling of the air after-cooler and of the oil
cooler is performed by the cooling air fan. The cool-
ing air fan also supplies the intake filter (Fig. 14/1)
with sufficient intake air.
The cooling air inlet and outlet openings must be
kept clear. The required cooling air rates must be
provided in accordance with the technical data for
the screw compressor.
The forced ventilation and bleeding
equipment must be dimensioned so
that the required supply and exhaust air
can be supplied and extracted taking
into account the existing residual thrust
from the cooling air fan. The exhaust
air can also be used for heat
reclamation.

Design and function
CAP-834 13
1.3.12Refrigeration dryer
Fig. 15: Refrigeration dryer
The refrigeration dryer (Fig. 15/1) dries the com-
pressed air using a heat exchange process. The
compressed air is fed from the oil separator tank
into the refrigeration dryer and then directed into the
compressed air network via the compressed air
port.
The condensate which accumulates is discharged
via the condensate drain (Fig. 15/2).
Depending on the variant, a hose for
discharging the condensate may
already be attached to the condensate
drain; otherwise, the user will need to
attach one.
1.4 Interfaces
Air supply
Fig. 16: Screw compressor with frequency converter, air
receiver (optional) and refrigeration dryer (optional) 3–
15 kW
The cooling air fan in the compressor housing di-
rects the fresh air to the intake filter and is also used
for process cooling. The intake filter filters the fresh
air and directs it into the compressor unit for com-
pression.
The refrigeration dryer (optional) in the upgrade
module has its own fan. It cools the compressed air
and extracts the heat.
Discharge port
Fig. 17: Discharge port
The air compressed by the compressor is available
to the compressed air network at the discharge
connection after it has been filtered and cooled.

Safety
CAP-834
14
2 Safety
This section is a summary of important safety as-
pects to ensure optimum protection of the personnel
and safe and trouble-free operation.
The owner, lessor or operator of this com-
pressor is hereby notified and forewarned that
failure to observe these safety precautions may
result in injury and/or property damage.
FS Curtis does not mean to imply that the following
safety precautions are all-inclusive or that the ob-
servance of these precautions will prevent all injury
or property damage.
FS Curtis expressly disclaims responsibility or
liability for any injury or property damage caused by
failure to follow these specified precautions or by
failure to exercise ordinary caution and due care
required in operating or handling this equipment
even though not expressly specified.
2.1 Symbols in these instructions
Safety instructions
The safety instructions and safety information in
these instructions are denoted by symbols. The
safety instructions are prefaced by signal words
which express the extent of the risk.
DANGER!
This combination of symbol and signal
word indicates a directly hazardous
situation which will lead to serious or
even fatal injuries if not avoided.
WARNING!
This combination of symbol and signal
word indicates a possibly hazardous
situation which may lead serious or
even fatal injuries if not avoided.
CAUTION!
This combination of symbol and signal
word indicates a possibly hazardous
situation which may cause minor or
light injuries if not avoided.
NOTICE!
This combination of symbol and signal
word indicates a possibly hazardous
situation which may cause material
damage if not avoided or possible
hazards for the environment.
Safety instructions in action sequences
Safety instructions may relate to certain, individual
instructions for actions. These safety instructions
are embedded in the instruction for action so that
they do not interrupt the flow of reading when per-
forming the action. The signal words described
above are used.
Example:
1.
Unfasten the screw.
2.
CAUTION!
Risk of entrapment on the cover!
Close the cover carefully.
3.
Tighten the screw.
Special safety instructions
The following symbols are used in conjunction with
the safety instructions in order to draw attention to
particular hazards:

Safety
CAP-834 15
Warning – high-voltage.
Warning – explosive
substances.
Warning – danger zone.
Tips and recommendations
This symbol indicates tips and
recommendations and information for
efficient and fault-free operation.
Further markings
The following markings are used in these instruc-
tions for emphasizing instructions for actions, re-
sults, lists, cross references and other elements:
Marking
Explanation
Step-by-step instructions for ac-
tions

Results of actions
References to sections of these
instructions and other applicable
documents
Lists without a set order
[Button]
Operating controls (e.g. buttons,
switches), display elements (e.g.
indicator lamps)
"Display"
Screen elements (e.g. buttons,
assignment of function keys)
2.2 Proper use
The machine is designed and constructed exclu-
sively for the proper use described here.
The screw compressor serves exclusively to gener-
ate compressed air in an environment not subject to
explosion. The screw compressor must be supplied
exclusively with cool, dry and dust-free cooling air.
Do not operate the compressor in excess of its
rated pressures and speeds indicated on the
compressor nameplate.
The proper use also includes adherence to all de-
tails in this manual.
Any use beyond the proper use or other type of use
counts as misuse.
WARNING!
Danger due to misuse!
- The compressed air may not be
used for breathing without
appropriate after-treatment.
- The compressed air may not be
used directly for pharmaceutical or
sanitary purposes or for the direct
handling of food without appropriate
after-treatment.
- The screw compressor may not be
operated outdoors.
- The screw compressor or individual
components may not be rebuilt,
modified or re-equipped.
- The screw compressor may not be
used in an atmosphere subject to
explosion.
- The intake of media other than cool,
dry and dust-free cooling air is
forbidden.
Claims of any type for damage due to misuse are
excluded.

Safety
CAP-834
16
2.3 General safety
1. Read and understand all the instructions found in
this manual before operating your compressor.
2. Disconnect the main power source before
working on or performing any maintenance
procedures on this unit. Use a lock out and tag
out process.
3. Do not attempt to remove any parts, break any
connection, loosen oil fill plug or drain plug until the
unit has been shut down and air pressure has been
relieved.
4. Do not operate the compressor in excess of its
rated pressures and speeds indicated on the com-
pressor nameplate.
5. Do not remove guards, shields, or screens while
the compressor is in operation. If removed for
maintenance replace before resuming operation.
6. Observe the delivery pressure gauge daily to be
sure the automatic control system is operating
within proper limits.
7. Periodically check all safety and relief devices for
proper operation.
8. Use compressed air properly. Pressurized air can
cause serious injury to personnel.
9. Be sure that no tools, rags or loose parts are left
in or on the compressor or drive parts.
10. Do not use flammable solvents for cleaning
parts.
11. Exercise cleanliness during maintenance and
when making repairs. Keep dirt away from parts and
exposed openings by covering with clean cloth or
Kraft paper.
12. Do not install a shut-off valve in the discharge
line without installing a pressure relief valve
between the shut-off and the compressor package.
13. Do not operate the compressor in areas where
there is a possibility of flammable or toxic
substances entering the system.
14. Never disconnect (or jump) the air discharge
temperature switch or any other safety device and
attempt to operate the compressor.
15. Know what mode of operation the compressor is
in before working around the unit. The power may
be on but the machine not running if it is in the auto
restart mode. Adhere to note #2 above.
2.4 Safety devices
WARNING!
Danger to life from nonfunctional
safety devices!
If safety devices are not functioning or
are disabled, there is a danger of grave
injury or death.
- Check that all safety devices are
fully functional and correctly
installed before starting work.
- Never disable or bypass safety
devices.
- Ensure that all safety devices are
always accessible.
2.4.1 Position of the safety devices
The following illustrations show the position of the
safety devices.
Fig. 18: Screw compressor with refrigeration dryer
(optional), tank (optional) and/or frequency converter 3 –
15 kW )

Safety
CAP-834 17
2.4.2 Description of the installed
safety devices
Emergency stop button
Fig. 19: Emergency stop button
By pressing the emergency stop button, the ma-
chine is stopped by an immediate switching off of
the power supply. After an emergency stop button
has been pressed, it must be unlocked by turning it
so that switching on is possible.
WARNING!
Danger to life from an unauthorized
restart!
An uncontrolled restart of the machine
may cause serious injuries including
death.
- Before switching the machine back
on, make sure the cause of the
emergency stop has been removed
and all safety devices have been
installed and function properly.
- Do not unlock the EMERGENCY-
STOP button until there is no more
danger.
Relief valves
Relief valves are unburdening equipment for areas
under pressure such as boilers, pressure vessels
and pipes. In case of an impermissible pressure
increase, relief valves bleed off gases, vapors or
liquids into the atmosphere.
Do not change the pressure setting of the pres-
sure relief valve, restrict the function of the re-
lief valve or replace the relief valve with a plug.
2.5 Environmental protection
NOTICE!
Danger to the environment from
incorrect handling of pollutants!
Incorrect handling of pollutants,
particularly incorrect waste disposal,
may cause serious damage to the
environment.
- Always observe the instructions
below regarding handling and
disposal of pollutants.
- Take the appropriate actions
immediately if pollutants escape
accidentally into the environment. If
in doubt, inform the responsible
municipal authorities about the
damage and ask about the
appropriate actions to be taken.
The following chemicals are used:
Oil
Oils can contain substances that are harmful to the
environment. They must not be allowed to escape
into the environment. Catch replaced oils in suitable
containers and dispose of in accordance with appli-
cable local, state and federal regulations
Lubricants
Lubricants such as greases and oils can contain
harmful substances. They must not be allowed to
escape into the environment. Dispose of lubricants
in accordance with applicable local, state and fed-
eral regulations.

Safety
CAP-834
18
2.6 Instructions on the machine
WARNING!
Danger of injury from illegible
symbols!
Stickers and signs can become dirty or
otherwise obscured over time, with the
result that dangers cannot be
recognized and the necessary
operating instructions cannot be
complied with. This, in turn, poses a
risk of injury.
- All safety, warning and operating
instructions must always be
maintained in a completely legible
condition.
- Damaged signs or stickers must be
replaced immediately.
Direction of rotation
There is a direction of rotation sticker on the drive
unit and on the cooling air ventilator. This sticker
shows the appropriate direction of rotation.
Hazardous Voltage

Safety
CAP-834 19
Brief instructions for operation
This sticker is on the enclosure and contains brief
instructions for operation.

Technical data
CAP-834
20
3 Technical data
For more information refer to the technical data sheet.
3.1 Serial tag
Fig. 20: Serial tag
The serial tag can be found on the enclosure. It includes the following details:
1. Manufacturer
2. Part number
3. Serial number
4. Motor power [HP]
5. Discharge pressure [PSI]
6. Voltage [V]
1
2
3
4
5
6