ESAB Caddy Arc 251i User manual

Caddy®
Instruction manual
0460 324 101 GB 20210831 Valid for: from serial no. 112-xxx-xxxx
Arc 251i

TABLE OF CONTENTS
0460 324 101 © ESAB AB 2021
1SAFETY ....................................................................................................... 4
1.1 Meaning of symbols ............................................................................... 4
1.2 Safety precautions ................................................................................. 4
2INTRODUCTION.......................................................................................... 7
2.1 Equipment ............................................................................................... 7
2.2 Control panel A32, A34 .......................................................................... 7
3TECHNICAL DATA ...................................................................................... 8
4INSTALLATION............................................................................................ 10
4.1 Location................................................................................................... 10
4.2 Mains supply........................................................................................... 10
4.3 Mains power supply ............................................................................... 10
4.3.1 Recommended fuse sizes and minimum cable area............................ 10
5OPERATION ................................................................................................ 11
5.1 Connections and control devices ......................................................... 11
5.2 Connection of welding and return cable .............................................. 11
5.3 TIG welding ............................................................................................. 11
5.4 Overheating protection .......................................................................... 12
6MAINTENANCE........................................................................................... 13
6.1 Power source.......................................................................................... 13
6.2 Welding torch.......................................................................................... 13
7TROUBLESHOOTING ................................................................................. 14
8ORDERING SPARE PARTS ........................................................................ 15
DIAGRAM ............................................................................................................ 16
ORDERING NUMBERS....................................................................................... 18
ACCESSORIES ................................................................................................... 19
Rights reserved to alter specifications without notice.

1 SAFETY
0460 324 101 -4- © ESAB AB 2021
1 SAFETY
1.1 Meaning of symbols
As used throughout this manual: Means Attention! Be Alert!
DANGER!
Means immediate hazards which, if not avoided, will result in immediate,
serious personal injury or loss of life.
WARNING!
Means potential hazards which could result in personal injury or loss of life.
CAUTION!
Means hazards which could result in minor personal injury.
WARNING!
Before use, read and understand the instruction manual
and follow all labels, employer´s safety practices and
Safety Data Sheets (SDSs).
1.2 Safety precautions
Users of ESAB equipment have the ultimate responsibility for ensuring that anyone who
works on or near the equipment observes all the relevant safety precautions. Safety
precautions must meet the requirements that apply to this type of equipment. The following
recommendations should be observed in addition to the standard regulations that apply to
the workplace.
All work must be carried out by trained personnel well-acquainted with the operation of the
equipment. Incorrect operation of the equipment may lead to hazardous situations which can
result in injury to the operator and damage to the equipment.
1. Anyone who uses the equipment must be familiar with:
○ its operation
○ location of emergency stops
○ its function
○ relevant safety precautions
○ welding and cutting or other applicable operation of the equipment
2. The operator must ensure that:
○ no unauthorised person is stationed within the working area of the equipment
when it is started up
○ no-one is unprotected when the arc is struck or work is started with the
equipment
3. The workplace must:
○ be suitable for the purpose
○ be free from drafts

1 SAFETY
0460 324 101 -5- © ESAB AB 2021
4. Personal safety equipment:
○ Always wear recommended personal safety equipment, such as safety glasses,
flame-proof clothing, safety gloves
○ Do not wear loose-fitting items, such as scarves, bracelets, rings, etc., which
could become trapped or cause burns
5. General precautions:
○ Make sure the return cable is connected securely
○ Work on high voltage equipment may only be carried out by a qualified
electrician
○ Appropriate fire extinguishing equipment must be clearly marked and close at
hand
○ Lubrication and maintenance must not be carried out on the equipment during
operation
WARNING!
Arc welding and cutting can be injurious to yourself and others. Take precautions
when welding and cutting.
ELECTRIC SHOCK - Can kill
• Install and ground the unit in accordance with instruction manual.
• Do not touch live electrical parts or electrodes with bare skin, wet gloves or
wet clothing.
• Insulate yourself from work and ground.
• Ensure your working position is safe
ELECTRIC AND MAGNETIC FIELDS - Can be dangerous to health
• Welders having pacemakers should consult their physician before welding.
EMF may interfere with some pacemakers.
• Exposure to EMF may have other health effects which are unknown.
• Welders should use the following procedures to minimize exposure to
EMF:
○ Route the electrode and work cables together on the same side of
your body. Secure them with tape when possible. Do not place your
body between the torch and work cables. Never coil the torch or work
cable around your body. Keep welding power source and cables as
far away from your body as possible.
○ Connect the work cable to the workpiece as close as possible to the
area being welded.
FUMES AND GASES - Can be dangerous to health
• Keep your head out of the fumes.
• Use ventilation, extraction at the arc, or both, to take fumes and gases
away from your breathing zone and the general area.
ARC RAYS - Can injure eyes and burn skin
• Protect your eyes and body. Use the correct welding screen and filter lens
and wear protective clothing.
• Protect bystanders with suitable screens or curtains.
NOISE - Excessive noise can damage hearing
Protect your ears. Use earmuffs or other hearing protection.

1 SAFETY
0460 324 101 -6- © ESAB AB 2021
MOVING PARTS - Can cause injuries
• Keep all doors, panels and covers closed and securely in place. Have only
qualified people remove covers for maintenance and troubleshooting as
necessary. Reinstall panels or covers and close doors when service is
finished and before starting engine.
• Stop engine before installing or connecting unit.
• Keep hands, hair, loose clothing and tools away from moving parts.
FIRE HAZARD
• Sparks (spatter) can cause fire. Make sure that there are no inflammable
materials nearby.
• Do not use on closed containers.
MALFUNCTION - Call for expert assistance in the event of malfunction.
PROTECT YOURSELF AND OTHERS!
CAUTION!
This product is solely intended for arc welding.
WARNING!
Do not use the power source for thawing frozen pipes.
CAUTION!
Class A equipment is not intended for use in residential
locations where the electrical power is provided by the
public low-voltage supply system. There may be
potential difficulties in ensuring electromagnetic
compatibility of class A equipment in those locations,
due to conducted as well as radiated disturbances.
NOTE!
Dispose of electronic equipment at the recycling
facility!
In observance of European Directive 2012/19/EC on
Waste Electrical and Electronic Equipment and its
implementation in accordance with national law,
electrical and/or electronic equipment that has reached
the end of its life must be disposed of at a recycling
facility.
As the person responsible for the equipment, it is your
responsibility to obtain information on approved
collection stations.
For further information contact the nearest ESAB dealer.
ESAB has an assortment of welding accessories and personal protection equipment
for purchase. For ordering information contact your local ESAB dealer or visit us on
our website.

2 INTRODUCTION
0460 324 101 -7- © ESAB AB 2021
2 INTRODUCTION
Arc 251i is a welding current power source intended for use with coated electrodes (MMA
welding) and TIG welding.
ESAB accessories for the product can be found in the "ACCESSORIES" chapter of
this manual.
2.1 Equipment
The power source is supplied with:
• Instruction manual for the welding power source
• Instruction manual for the control panel
• 3 m return cable
• 3 m welding cable
Instruction manuals in other languages can be downloaded from the Internet: www.esab.com
2.2 Control panel A32, A34
Welding process parameters are controlled via the control panel.
See the separate instruction manual for a detailed description of the control panels.

3 TECHNICAL DATA
0460 324 101 -8- © ESAB AB 2021
3 TECHNICAL DATA
Arc 251i
Mains voltage 400V ±15%, 3~ 50/60Hz
Mains supply Ssc min 3.3MVA
Primary current
Imax MMA 14A
Imax TIG 10A
No-load power demand when in the
energy-saving mode, 6.5 min. after welding
30W
Setting range
MMA 4–250A
TIG 3–250A
Permissible load at MMA
30% duty cycle 250A / 30V
60% duty cycle 190A / 27.6V
100% duty cycle 150A / 26V
Permissible load at TIG
30% duty cycle 250A / 20V
60% duty cycle 190A / 17.6V
100% duty cycle 150A / 16V
Power factor at maximum current
MMA 0.94
TIG 0.93
Efficiency at maximum current
MMA 83%
TIG 79%
Open-circuit voltage
without VRD 65V
with VRD <35V
Operating temperature -10 to +40°C (+14 to +104°F)
Transportation temperature -20 to +55°C (-4 to +131°F)
Continual sound pressure at no-load <70db(A)
Dimensions lxwxh 418×188×208mm
(16.5×7.4×8.2in.)
Weight 10.5kg (23.1lb)
Insulation class transformer H
Enclosure class IP23
Application class
Mains supply, Ssc min
Minimum short circuit power on the network in accordance with IEC 61000-3-12.

3 TECHNICAL DATA
0460 324 101 -9- © ESAB AB 2021
Duty cycle
The duty cycle refers to the time as a percentage of a ten-minute period that you can weld or
cut at a certain load without overloading. The duty cycle is valid for 40°C/104°F, or below.
Enclosure class
The IP code indicates the enclosure class, i.e. the degree of protection against penetration
by solid objects or water.
Equipment marked IP23 is intended for indoor and outdoor use.
Application class
The symbol indicates that the power source is designed for use in areas with increased
electrical hazard.

4 INSTALLATION
0460 324 101 - 10 - © ESAB AB 2021
4 INSTALLATION
The installation must be carried out by a professional.
4.1 Location
Position the power source so that its cooling air inlets and outlets are not obstructed.
4.2 Mains supply
NOTE!
Mains supply requirements
This equipment complies with IEC 61000-3-12 provided that the short-circuit power
is greater than or equal to Sscmin at the interface point between the user's supply
and the public system. It is the responsibility of the installer or user of the equipment
to ensure, by consultation with the distribution network operator if necessary, that
the equipment is connected only to a supply with a short-circuit power greater than
or equal to Sscmin. Refer to the technical data in the TECHNICAL DATA chapter.
4.3 Mains power supply
Make sure that the welding power source is connected to the correct supply voltage and that
it is protected by the correct fuse rating. A protective earth connection must be made in
accordance with regulations.
Rating plate with supply connection data
4.3.1 Recommended fuse sizes and minimum cable area
Arc 251i
Mains voltage 400 V
Mains cable area (mm2)4 G 1.5
Phase current (I1eff ) 8 A
Fuse
anti-surge 10 A
type C MCB 10 A
NOTE!
The mains cable areas and fuse sizes as shown above are in accordance with
Swedish regulations. For other regions, supply cables must be suitable for the
application and meet local and national regulations.

5 OPERATION
0460 324 101 - 11 - © ESAB AB 2021
5 OPERATION
General safety regulations for handling the equipment can be found in the "SAFETY"
chapter of this manual. Read it through before you start using the equipment!
5.1 Connections and control devices
1 Mains voltage switch 4 Connection for remote control unit
2 Connection (+)
TIG: return cable
MMA: welding cable or return cable
5 Control panel,
see separate instruction manual
3 Connection (-)
TIG: torch
MMA: return cable or welding cable
5.2 Connection of welding and return cable
The power source has two outputs, a positive terminal (+) and a negative terminal (-), for
connecting welding and return cables. The output to which the welding cable is connected
depends on the type of electrode used. The connecting polarity is stated on the electrode
packaging.
Connect the return cable to the other output on the power source. Secure the return cable's
contact clamp to the work piece and ensure that there is good contact between the work
piece and the output for the return cable on the power source.
5.3 TIG welding
At TIG-welding complete the power source with:
• a TIG torch with gas valve
• an argon gas tube
• an argon gas regulator
• tungsten electrode

5 OPERATION
0460 324 101 - 12 - © ESAB AB 2021
5.4 Overheating protection
The welding power source has overheating protection that operates if the temperature
becomes too high. When this occurs the welding current is interrupted and a fault code is
displayed on the control panel.
The overheating protection resets automatically when the temperature has fallen.

6 MAINTENANCE
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6 MAINTENANCE
NOTE!
Regular maintenance is important for safe and reliable operation.
CAUTION!
Only persons with the appropriate electrical knowledge (authorised personnel) may
remove the safety plates.
CAUTION!
All warranty undertakings from the supplier cease to apply if the customer attempts
any work to rectify any faults in the product during the warranty period.
6.1 Power source
Check regularly that the welding power source is not clogged with dirt.
How often and which cleaning methods apply depend on:
• the welding process
• arc times
• positioning of welding power source
• the surrounding environment.
It is normally sufficient to blow the power source clean with dry compressed air (reduced
pressure) once a year.
Clogged or blocked air inlets and outlets otherwise result in overheating.
6.2 Welding torch
The wear parts should be cleaned and replaced at regular intervals in order to achieve
trouble-free welding.

7 TROUBLESHOOTING
0460 324 101 - 14 - © ESAB AB 2021
7 TROUBLESHOOTING
Try these recommended checks and inspections before sending for an authorized service
technician.
Type of fault Corrective actions
No arc. • Check that the mains power supply switch is turned on.
• Check that the welding current supply and return cables
are correctly connected.
• Check that the correct current value is set.
• Check the mains power supply fuses.
The welding current is
interrupted during welding.
• Check whether the thermal overload protections have
tripped (a fault code is displayed on the control panel).
• Check the mains power supply fuses.
The thermal overload
protection trips frequently.
• Make sure that you are not exceeding the rated data for
the welding power source (i.e. that the unit is not being
overloaded).
• Check that the welding power source is not clogged with
dirt.
Poor welding performance. • Check that the welding current supply and return cables
are correctly connected.
• Check that the correct current value is set.
• Check that the correct electrodes are being used.

8 ORDERING SPARE PARTS
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8 ORDERING SPARE PARTS
Arc 251i is designed and tested in accordance with the international and European
standards EN 60974-1 and EN 60974-10. It is the obligation of the service unit which has
carried out the service or repair work to make sure that the product still conforms to the
mentioned standard.
Spare parts and wear parts can be ordered through your nearest ESAB dealer, see
esab.com. When ordering, please state product type, serial number, designation and spare
part number in accordance with the spare parts list. This facilitates dispatch and ensures
correct delivery.

DIAGRAM
0460 324 101 - 16 - © ESAB AB 2021
DIAGRAM

DIAGRAM
0460 324 101 - 17 - © ESAB AB 2021

ORDERING NUMBERS
0460 324 101 - 18 - © ESAB AB 2021
ORDERING NUMBERS
Ordering no. Denomination Type
0460 300 880 Welding power source Caddy® Arc 251i, A32
0460 300 881 Welding power source Caddy® Arc 251i, A34
0459 839 021 Spare parts list Arc 251i
0460 449 * Instruction manual Control panel Caddy® A32, A34
The three last digits in the document number of the manual show the version of the manual.
Therefore they are replaced with * here. Make sure to use a manual with a serial number or
software version that corresponds with the product, see the front page of the manual.
Instruction manuals and the spare parts list are available on the Internet at: www.esab.com

ACCESSORIES
0460 324 101 - 19 - © ESAB AB 2021
ACCESSORIES
0459 491 896 Remote control unit AT1
MMA and TIG: setting of current
0459 491 897 Remote control unit AT1 CF
MMA and TIG: rough and fine setting of
current
0349 090 886 Foot pedal FS002 with 5 m cable

0459 552 880
0459 552 881
0459 552 882
0459 552 883
Remote cable 12 pole - 8 pole
5 m
10 m
15 m
25 m
0700 006 902
0700 006 903
Welding cable kit
Return cable kit
0460 265 002 Cable holder
0460 265 003 Shoulder strap
0700 300 539
0700 300 545
0700 300 553
0700 300 556
Tig torch TXH 151V 4 m
Tig torch TXH 151V 8 m
Tig torch TXH 201V 4 m
Tig torch TXH 201V 8 m

ACCESSORIES
0460 324 101 - 20 - © ESAB AB 2021

0459 366 885
Trolley
for 5-10 litre gascylinder

0459 366 886
Trolley
for 20-50 litre gascylinder

0460 330 880
Trolley
for 20-50 litre gascylinder