Lincoln Electric REDI-MIG 255 Integrated User manual

IMA 598B
February 2004
OPERATING MANUAL
THE LINCOLN ELECTRIC COMPANY
(AUSTRALIA) PTY. LTD. A.B.N. 36 000 040 308
SYDNEY. AUSTRALIA
A Subsidiary of
THE LINCOLN ELECTRIC CO. U.S.A.
Associated Subsidiaries in Australasia, Asia, Canada, Europe, North and South America.
THE WORLD’S LEADER IN WELDING AND CUTTING PRODUCTS
SAFETY DEPENDS ON YOU
Lincoln Electric welders are designed and built with safety in mind. However, your overall safety can be
increased by proper installation and thoughtful operation on your part. Read and observe the general safety
precautions on page 2 and follow specific installation and operating instructions included in this manual.
Most importantly, think before you act and be careful.
REDI-MIG 255 Integrated
REDI-MIG 255 Remote
Semi Automatic Arc Welding Machine
for codes 70037 and above
EMC Compliant
Part No. Description Input Volts
KA1432-1 REDI-MIG 255i 240
KA1432-11 REDI-MIG 255i 220
KA1432-2 REDI-MIG 255R 240
KA1432-12 REDI-MIG 255R 220

Page 2 REDI-MIG 255 IMA 598B
PROTECT YOURSELF AND OTHERS FROM POSSIBLE SERIOUS INJURY OR DEATH. READ AND UNDERSTAND BOTH
THE SPECIFIC INFORMATION GIVEN IN THE OPERATING MANUAL FOR THE WELDER AND/OR OTHER EQUIPMENT
TO BE USED AS WELL AS THE FOLLOWING GENERAL INFORMATION.
ARC WELDING SAFETY PRECAUTIONS
1. a. The electrode and work (or ground) circuits are
electrically “hot” when the welder is on. Do not touch
these “hot” parts with your bare skin or wet clothing.
Wear dry, hole-free gloves to insulate hands.
b. In semi-automatic and automatic wire welding, the
electrode, electrode reel, welding head and nozzle or
semi-automatic welding gun are also electrically “hot”.
c. Insulate yourself from work and ground using dry
insulation. When welding in damp locations, on metal
framework such as floors, gratings or scaffolds, and
when in positions such as sitting or Lying, make certain
the insulation is large enough to cover your full area of
physical contact with work and ground.
d. Always be sure the work cable makes a good electrical
connection with the metal being welded. The
connection should be as close as possible to the area
being welded.
e. Ground the work or metal to be welded to a good
electrical (earth) ground.
f. Maintain the electrode holder, work clamp, welding
cable and welding machine in good, safe operating
condition. Replace damaged insulation.
g. Never dip the electrode holder in water for cooling.
h. Never simultaneously touch electrically “hot” parts of
electrode holders connected to two welders because
voltage between the two can be the total of the open
circuit voltage of both welders.
i. When working above floor level, protect yourself from
a fall should you get a shock.
j. Also see items 4c and 6.
2. a. Welding may produce fumes and gases hazardous to
health. Avoid breathing these fumes and gases. When
welding, keep your head out of the fume. Use enough
ventilation and/or exhaust at the arc to keep fumes and
gases away from the breathing zone. When welding
on galvanised, lead or cadmium plated steel and other
metals which produce toxic fumes, even greater care
must be taken.
b. Do not weld in locations near chlorinated hydrocarbon
vapours coming from degreasing, cleaning or spraying
operations. The heat and rays of the arc can react with
solvent vapours to form phosgene, a highly toxic gas,
and other irritating products.
c. Shielding gases used for arc welding can displace air
and cause injury or death. Always use enough
ventilation, especially in confined areas, to ensure
breathing air is safe.
d. Read and understand the manufacturer’ s instructions
for this equipment and the consumables to be used,
including the material safety data sheet (MSDS) and
follow your employer’s safety practices.
e. Also see Item 7b.
3. a. Use a shield with the proper filter and cover plates to
protect your eyes from sparks and the rays of the arc
when welding or observing open arc welding.
Headshield and filter lens should conform to AS
1674.2-1990 standards.
b. Use suitable clothing made from durable flame
resistant material to protect your skin and that of your
helpers from the arc rays.
c. Protect other nearby personnel with suitable non
flammable screening and/or warn them not to watch
the arc or expose themselves to the arc rays or to hot
spatter or metal.
4. a. Remove fire hazards from the welding area. If this is
not possible, cover them to prevent the welding sparks
from starting a fire. Remember that welding sparks
and hot materials from welding can easily go through
small cracks and openings to adjacent areas. Have a
fire extinguisher readily available.
b. Where compressed gases are to be used at the job
site, special precautions should be used to prevent
hazardous situations. Refer to AS1674 Parts 1 & 2
“Safety in Welding and Allied Processes”, WTIA
Technical Note 7 “Health and Safety in Welding” and
the operating information for the equipment being
used.
c. When not welding, make certain no part of the
electrode circuit is touching the work or ground.
Accidental contact can cause overheating and create
a fire hazard.
d. Do not heat, cut or weld tanks, drums or containers
until the proper steps have been taken to insure that
such procedures will not cause flammable or toxic
vapours from substances inside. These can cause an
explosion even though the vessel has been “cleaned”.
For information purchase AS 1674-1990.
e. Vent hollow castings or containers before heating,
cutting or welding. They may explode.
f. Sparks and spatter are thrown from the welding arc.
Wear oil free protective garments such as leather
gloves, heavy shirt, cuffless trousers, high shoes and
a cap over your hair. Wear ear plugs when welding out
of position or in confined places. Always wear safety
glasses with side shields when in a welding area.
g. Connect the work cable to the work as close to the
welding area as possible. Work cables connected to
the building framework or other locations away from
the welding area increase the possibility of the welding
current passing through lifting chains, crane cables or
other alternate circuits. This can create fire hazards or
overheat lifting chains or cables until they fail.
h. Also see Item 7c.
ELECTRIC SHOCK can kill
FUMES AND GASES
can be dangerous
ARC RAYS can burn
WELDING SPARKS can
cause fire or explosion

IMA 598B REDI-MIG 255 Page 3
5. a. Use only compressed gas cylinders containing the
correct shielding gas for the process used and
properly operating regulators, designed for the gas
and pressure used. All hoses, fittings, etc. should be
suitable for the application and maintained in good
condition.
b. Always keep cylinders in an upright position and
securely chained to an undercarriage or fixed support.
c. Cylinders should be located :
• Away from areas where they may be struck or
subjected to physical damage.
• A safe distance from arc welding or cutting
operations and any other source of heat, sparks or
flame.
d. Never allow the electrode, electrode holder, or any
other electrically “hot” parts to touch a cylinder.
e. Keep your head and face away from the cylinder valve
outlet when opening the cylinder valve.
f. Valve protection caps should always be in place and
hand-tight except when the cylinder is in use or
connected for use.
g. Read and follow the instructions on compressed gas
cylinders and associated equipment, and AS 2030
Parts 1 & 2.
6. a. Turn off input power using the disconnect switch at the
fuse box before working on the equipment.
b. Install equipment in accordance with the SAA Wiring
Rules, all local codes and the manufacturer’s
recommendations.
c. Ground the equipment in accordance with the SAA
Wiring Rules and the manufacturer’s
recommendations.
7. a. Turn the engine off before troubleshooting
and maintenance work unless the
maintenance work requires it to be
running.
b. Operate engines in open, well ventilated
areas or vent the engine exhaust fumes
outdoors.
c. Do not add fuel near an open flame,
welding arc or when the engine is running.
Stop the engine and allow it to cool before
refuelling to prevent spilled fuel from
vaporizing on contact with hot engine
parts and igniting. Do not spill fuel when
filling tank. If fuel is spilled, wipe it up and
do not start engine until fumes have been
eliminated.
d. Keep all equipment, safety guards, covers
and devices in position and in good repair.
Keep hands, hair, clothing and tools away
from V-belts, gears, fans and all other
moving parts when starting, operating or
repairing equipment.
e. In some cases it may be necessary to
remove safety guards to perform required
maintenance. Remove guards only when
necessary and replace them when the
maintenance requiring their removal is
complete. Always use the greatest care
when working near moving parts.
f. Do not put your hands near the engine
fan. Do not attempt to override the
governor or idler by pushing on the throttle
control rods while the engine is running.
g. To prevent accidentally starting petrol
engines while turning the engine or
welding generator during maintenance
work, disconnect the spark plug wires,
distributor cap or magneto wire as
appropriate.
h. To avoid scalding do not remove the
radiator pressure cap when the engine is
hot.
CYLINDER may explode if
damaged
FOR ELECTRICALLY
powered equipment
FOR ENGINE
powered equipment
HAVE ALL INSTALLATIONS, OPERATION, MAINTENANCE AND REPAIR WORK PERFORMED BY QUALIFIED PEOPLE
HOW TO ORDER REPLACEMENT PARTS
To ensure that you receive the correct replacement part the following procedure should be followed:
1. Quote Serial Number and Code Number.
2. Quote the Description, Item Number and Parts List Number of the desired part. When ordering parts for items carrying brand
names of other companies, such as fan motors, drive shafts, etc., be sure to include the other company’s name and part number
and other relevant information.
3. Should the primary cord be damaged, a special cord is required, and is available from Lincoln Electric.
4. Parts should be ordered from Lincoln, its offices or the nearest Authorised Field Service Shop. (The “Lincoln Service Directory”
listing these shops geographically is available on request.)
Note: “Hardware” in the Lincoln Parts Lists are not Lincoln stock items but can be obtained via the Field Service Shop network.
Component parts of assemblies such as stator coils or armature coils, etc., which require electrical testing or locating fixtures are not
considered replaceable items. This is to ensure that the customer receives parts which will keep the welder in the best operating condition.
BUY ONLY GENUINE REPAIR PARTS
For more detailed information it is strongly recommended that you purchase a copy of “Safety in Welding and Cutting - ANSI Standard Z
49.1” and WTIA Technical Note 7. All WTIA publications and ANSI/AWS Standards are available from the Welding Technology Institute of
Australia, P.O. Box 6165, Silverwater NSW 2128. For copies of various Australian Standards contact your local S.A.A. office.

Page 4 REDI-MIG 255 IMA 598B
WELDING, EMF & PACEMAKERS
All welders should follow safe practices that minimise their
exposure to electric and magnetic fields (EMF).
For welders wearing implanted pacemakers, safe welding
practices are particularly important and additional procedures
should be followed by those who have decided to continue to
weld. (Hopefully in keeping with a doctor’s advice).
The following procedures will not eliminate exposure to EMF or
the possibility of arc welding having an effect on a pacemaker,
however if followed, they will significantly reduce exposure to
electric and magnetic fields. Electric and magnetic fields are
created any time electric current flows through a conductor,
however it is not clear whether such exposure affects ones
health.
Some researchers have reported that exposure to EMF may
cause leukemia or other illnesses. These claims originally arose
in relation to high voltage electric power lines and are very much
in dispute in the medical and scientific arena, however the best
advice is to minimise your exposure to EMF to protect your health
should doctors eventually decide there is a risk.
There are four fundamental facts about EMF:
• With direct current (DC), the field strength is relatively
constant and does not change.
• With alternating current (AC), the field strength constantly
changes.
• The greater the current flow, i.e. the higher the amps, the
stronger the field created by the current
• The closer the conductor or electrical device is to the body,
the greater the exposure to the field.
Minimising exposure
All welders should use the following procedures to minimise EMF
exposure.
• Route electrode or gun and work cables together. Secure
them with tape if possible.
• Never coil the electrode lead around your body.
• Do not place your body between the electrode and work
cables. If your electrode cable is on your right side the work
cable should also be on your right side.
• Connect the work cable to the work piece as close as
possible to the area being welded. (This is also a good
practice to eliminate a common problem on welding - a
poor work connection.
• Do not work next to the welding power source.
Welders with pacemakers
There is no question that the fields in arc welding can interfere
with a pacemakers function. Generally the interference does not
permanently damage the pacemaker. Once the wearer leaves the
arc welding environment or stops welding, the pacemaker returns
to normal functioning. The welding arc has little or no effect on the
operation of some pacemakers, especially designs that are bi-
polar or designed to filter out such interference.
For a welder or anyone working around electrical equipment the
selection of a pacemaker is very important. Get a doctor’s advice
about which pacemaker is the least sensitive to interference from
welding while still being medically suitable.
In addition to the normal safety precautions, the following
additional procedures should be adopted by welders with
pacemakers.
• Use gas welding when the application is suitable.
• Use the lowest current setting appropriate for the
application. Do not exceed 400 amps. Low current
(75-200 amps) direct current (DC) welding should be used
if arc welding is necessary. Do not TIG weld with high
frequency.
• Do not use repeated, short welds. Wait about ten seconds
between stopping one weld and starting the next. When
having difficulty starting an electrode, do not re-strike the
rod repeatedly.
• If you feel light headed, dizzy or faint, immediately stop
welding. Lay the electrode holder down so that it does not
contact the work and move away from any welding being
performed. Arrange your work in advance so that, if you
become dizzy and drop the electrode holder, the electrode
holder will not fall on your body or strike the work.
• Do not work on a ladder or other elevated position or in a
cramped, confined place.
• Do not work alone. Work only in the presence of an
individual who understands these precautions and the
possible effect welding may have on your pacemaker.
• Do not work near spot welding equipment.
• If you have a pacemaker and wish to continue arc welding,
discuss this and any other questions you may have with
your physician and follow his or her advice. The doctor may
wish to contact the pacemaker manufacturer for a
recommendation. As mentioned before, the design of the
pacemaker significantly affects the degree to which it is
subject to interference from a welding circuit. Do not rely on
the fact that you know another welder with a pacemaker
who has welded for years without experiencing a problem.
That welder and his or her pacemaker may be quite
different from you and your pacemaker.

IMA 598B REDI-MIG 255 Page 5
Conformance
Products displaying the C-Tick mark are in conformity with
Australian/New Zealand requirements for Electromagnetic
Compatibility (EMC). They are:
• manufactured in conformity with Australian/New Zealand
Standard (Emission):- AS/NZS 3652 ‘Electromagnetic
Compatibility - Arc Welding Equipment’ (Identical to and
reproduced from British Standard EN 50199)
• for using with other Lincoln Electric/LiquidArc equipment.
• designed for industrial and professional use.
Introduction
All electrical equipment generates small amounts of
electromagnetic emission. Electrical emission may be transmitted
through power lines or radiated through space, similar to a radio
transmitter. When emissions are received by other equipment,
electrical interference may result. Electrical emissions may effect
many kinds of electrical equipment: other nearby welding
equipment, radio and TV transmitters and receivers, numerical
controlled machines, telephone systems, computers, etc. Be
aware that interference may result and extra precautions may be
required when a welding power source is used in a domestic
establishment.
Installation and Use
The purchaser/user is responsible for installing and using the
welding equipment according to the manufacturer’s instructions.
If electromagnetic disturbances are detected then it shall be the
responsibility of the purchaser/user of the welding equipment to
resolve the situation with the technical assistance of the
manufacturer. In some cases this remedial action may be as
simple as earthing (grounding) the welding circuit (see note
below). In other cases it could involve constructing an
electromagnetic screen enclosing the power source and the work
complete with associated input filters. In all cases
electromagnetic disturbances must be reduced to the point where
they are no longer troublesome.
Note: The welding circuit may or may not be earthed for safety
reasons according to national codes. Changing the earthing
arrangements should only be authorised by a person who is
competent to assess whether the changes increase the risk of
injury, eg. by allowing parallel welding current return paths which
may damage the earth circuits of other equipment.
Assessment of Area
Before installing welding equipment the purchaser/user shall
make an assessment of potential problems in the surrounding
area.
The following shall be taken into account:
a. Other supply cables, control cables, signalling and
telephone cables above, below and adjacent to the welding
equipment;
b. Radio and television transmitters and receivers;
c. Computer and other control equipment;
d. Safety critical safety equipment, eg. guarding of industrial
equipment;
e. The health of people around, eg. the use of pacemakers
and hearing aids;
f. Equipment used for calibration or measurement;
g. The immunity of other equipment in the environment. The
purchaser/user shall ensure that other equipment being
used in the environment is compatible. This may require
additional protection measures;
h. The time of the day that welding or other activities are to be
carried out.
The size of the surrounding area to be considered will depend on
the structure of the building and other activities that are taking
place. The surrounding area may extend beyond the boundaries
of the premises.
Methods of Reducing Emissions
Mains Supply
Welding equipment should be connected to the mains supply
according to the manufacturer’s recommendations.If interference
occurs, it may be necessary to take additional precautions such
as filtering the mains supply. Consideration should be given to
shielding the supply cable of permanently installed welding
equipment in metallic conduit or equivalent. Shielding should be
electrically continuous throughout its length. The shielding should
be connected to the welding power source so that good electrical
contact is maintained between the conduit and the welding power
source enclosure.
Maintenance of the Welding Equipment
The welding equipment should be routinely maintained according
to the manufacturer’s recommendations. All access and service
doors and covers should be closed and properly fastened when
the welding equipment is in operation. The welding equipment
should not be modified in any way except for those changes and
adjustment covered in the manufacturer’s instructions. In
particular, the spark gaps of arc initiation and stabilising devices
should be adjusted and maintained according to the
manufacturer’s recommendations.
Welding Cables
The welding cables should be kept as short as possible and
should be positioned close together, running at or close to the
floor level.
Equipotential Bonding
Bonding of all metallic components in the welding installation and
adjacent to it should be considered. However, metallic
components bonded to the work piece will increase the risk that
the operator could receive a shock by touching these metallic
components and the electrode at the same time. The operator
should be insulated from all such bonded metallic components.
Earthing of the workpiece
Where the workpiece is not bonded to earth for electrical safety,
nor connected to earth because of its size and position, eg. ship’s
hull or building steelwork, a connection bonding the workpiece to
earth may reduce emissions in some, but not all instances. Care
should be taken to prevent the earthing of work pieces increasing
the risk of injury to users, or damage to other electrical
equipment. Where necessary, the connection of the workpiece to
earth should be made by direct connection to the workpiece, but
in some countries where direct connection is not permitted, the
bonding should be achieved by suitable capacitance, selected
according to national regulations.
Screening and Shielding
Selective screening and shielding of other cables and equipment
in the surrounding area may alleviate problems of interference.
Screening of the entire welding installation may be considered for
special applications.*
* Portions of the preceding text are contained in AS/NZS3652:
‘Electromagnetic Compatibility - Arc Welding Equipment’.
INSTRUCTIONS FOR ELECTROMAGNETIC COMPATIBILITY
This welding machine must be used by trained operators
only. Read this manual carefully before attempting to use
the welding machine.
WARNING

Page 6 REDI-MIG 255 IMA 598B
Thank You for selecting a QUALITY product by Lincoln Electric. We want you to
take pride in operating this Lincoln Electric Company product - as much
pride as we have in bringing this product to you!
Please record your equipment identification information below for future reference. This information can be found
on your machine nameplate.
Model Name & Number________________________________________________
Code & Serial Number ________________________________________________
Date of Purchase ____________________________________________________
Whenever you request replacement parts or information on this equipment, always supply the information you
have recorded above.
Read this Operator’s Manual completely before attempting to use this equipment. Save this manual and keep it
handy for quick reference. Pay particular attention to the Safety Instructions we have provided for your protection. The
level of seriousness to be applied to each is explained below:
This statement appears where the information must be
followed exactly to avoid serious personal injury or loss of
life.
WARNING
This statement appears where the information must be
followed to avoid minor personal injury or damage to this
equipment.
CAUTION

IMA 598B REDI-MIG 255 Page 7
Page
Section 1 INSTALLATION 8
1.1 Location 8
1.2 Connection to Mains Supply 8
1.3 Shielding Gas Supply (for the Gas Metal Arc Welding Process) 9
1.4 Gun and Cable Installation 9
1.5 Output Polarity Connection 9
Section 2 OPERATING INSTRUCTIONS 10
2.1 Duty Cycle 10
2.2 Control Panel 10
Section 3 SETTING UP FOR WELDING 11
Section 4 WELDING 13
4.1 Changing Electrode Size and Type 13
4.2 Adjusting Spool Tension 13
Section 5 LEARNING TO WELD 13
5.1 The Arc-Welding Circuit 13
5.2 The Self-Shielded (Gasless) FCAW Welding Arc 14
5.3 The GMAW (MIG) Welding Arc 14
5.4 Process Selection 14
5.5 Common Metals 14
5.6 Machine Set Up for the Self-Shielded (Gasless) FCAW Process 14
5.7 Welding Techniques for the Self-Shielded (Gasless) FCAW Process 15
5.8 Machine Set Up for the GMAW (MIG) and Gas-Shielded FCAW Processes 16
5.9 Welding Techniques for the GMAW (MIG) Process 16
5.10 Joint Types and Positions 17
5.11 Butt Welds 17
5.12 Penetration 17
5.13 Fillet Welds 18
5.14 Welding in the Vertical Position 18
5.15 Vertical-Up and Overhead Welding 18
5.16 Vertical-Down Welding 18
5.17 Troubleshooting Welds 18
Section 6 MAINTENANCE 19
6.1 Routine Maintenance 19
6.2 Gun and Cable Maintenance 19
6.3 Gun Tips and Nozzles 19
6.4 Input Lead 19
6.5 Liner Removal, Installation and Trimming Instructions
for REDI-MIG 240 MIG Gun 20
Section 7 ACCESSORIES 20
Section 8 GROUND TEST PROCEDURE 20
Section 9 TROUBLESHOOTING 21
PARTS LISTS REDI-MIG 255 23
WIRING DIAGRAM REDI-MIG 255 Remote 31
WIRING DIAGRAM REDI-MIG 255 Integrated 32
PARTS LISTS REDI-MIG 4D Remote 33
WIRING DIAGRAM REDI-MIG 4D Remote Wire Feeder 37
WIRE DRIVE ASSEMBLY 38
PARTS LISTS REDI-MIG 240 MIG GUN 40
INDEX

Machine Installation
1.1 Location
Place the welder where clean cooling air can freely
circulate in through the front louvers and out through the
rear louvers. Dirt, dust or any foreign material that can be
drawn into the welder should be kept at a minimum. Failure
to observe these precautions can result in excessive
operating temperatures and nuisance thermostat trips.
1.2 Connection to Mains Supply
Before connecting the machine to the mains supply check
that the voltage and current capacity correspond to the
machine voltage and rated input current. Use a fuse or C/B
per AS3000 or local wiring rules.
The machine is supplied with an input lead fitted.
Have a qualified electrician fit a suitable input plug.
Page 8 REDI-MIG 255 IMA 598B
• Turn the input power off at the
disconnect switch before installing
or servicing this machine.
• Do not touch electrically
“hot” parts such as output
terminals or internal wiring.
• Connect earthing screw ( ) to
a good earth ground.
• Do not operate with covers
removed.
• Turn power switch “off” before
connecting or disconnecting
cables or other equipment.
WARNING
HIGH
VOLTAGE
can kill
Only qualified personnel should install or service this equipment.
PRODUCT DESCRIPTION
The REDI-MIG 255 Integrated is a fully integrated semi-automatic Constant Voltage DC arc welding machine. The REDI-MIG 255 Remote
offers a remote wire feeder and a separate Constant Voltage DC arc welding machine. They combine a solid state power source with
electronically controlled wire feeding equipment.
Excellent arc characteristics are provided for both gas shielded and self shielded welding within its current range.
Standard features include output volt and amp meters, a spot timer, gas purge facilities, wire inch, burnback control, a dual position 2 or 4
step trigger interlock, a REDI-MIG 240 MIG gun, a Harris 801 regulator/flowmeter and gas hose, ground cable assembly, (3m on the REDI-
MIG 255 Integrated and 5m on the REDI-MIG 255 Remote), a 3m long input lead and an easy load cylinder undercarriage on which a gas
cylinder can be mounted.
SECTION 1 - INSTALLATION
Never connect the green/yellow conductor to any of the
active supply lines from the mains. This conductor is to
earth the machine as required by Electrical Regulations.
Once the above has been followed the machine can be
plugged into the mains outlet.
CAUTION
* Dimensions do not include Wire Feeder
Model REDI-MIG 255 Integrated REDI-MIG 255 Remote
Part No. KA1432-1 (240V) KA1432-11 (220V) KA1432-2 (240V) KA1432-12 (220V)
Maximum Open Circuit Voltage 43V
Output Current Range 20 to 300A
Duty Cycle 30% 60% 100%
Rated Output 255A/26.5V 180A/23V 120A/20V
Rated Input 240V 1ph 50Hz 25A 220V 1ph 50Hz 27A 240V 1ph 50Hz 25A 220V 1ph 50Hz 27A
Wire Speed Range 1-20 m/min
Weight (complete with u/c) 112 kg 129kg
H x W x L (mm) Over handle
cylinder tray & wheels 760 x 447 x 905 mm 760 x 447 x 905 mm*
Operating Temperature -20˚C to 40˚C
Specifications

IMA 598B REDI-MIG 255 Page 9
1.3 Shielding Gas Supply (For the Gas Metal
Arc Welding Process)
Refer “Safety in welding and cutting” - ANSI Standard Z49-
1 and WTIA Technical Note 7, available from the Welding
Technology Institute of Australia.
Obtain cylinder of appropriate type shielding gas for the
process being used.
1. Set gas cylinder on rear platform of the machine. Hook
chain in place to secure cylinder to rear of welder.
2. Remove the cylinder cap. Inspect the cylinder valve for
damaged threads, dirt and dust. For cylinders having an
external thread fitting, remove any dust and dirt from the
threads with a clean cloth.
DO NOT ATTACH THE REGULATOR/FLOWMETER IF
OIL, GREASE OR CYLINDER VALVE DAMAGE IS
PRESENT. OIL OR GREASE IN THE PRESENCE OF
HIGH PRESSURE OXYGEN IS EXPLOSIVE! Inform your
gas supplier of this condition.
3. Stand to one side away from the outlet and open the
cylinder valve for an instant. This blows away any dust or
dirt which may have accumulated in the valve outlet.
4. Inspect the regulator/flowmeter for damaged threads and
seals, dirt and dust. Remove dust and dirt with a clean
cloth.
DO NOT USE THE REGULATOR/FLOWMETER IF
DAMAGE IS PRESENT! Have an authorised repair station
repair any damage.
5. Attach the regulator/flowmeter to the cylinder valve and
tighten the union nut(s) securely with a spanner.
6. Attach the machines inlet gas hose to the outlet fitting of the
regulator/flowmeter, and tighten the union nut securely with
a spanner.
7. Before opening the cylinder valve, turn the regulator
adjusting knob counter-clockwise until the adjusting spring
pressure is released.
8. Open the cylinder valve slowly a fraction of a turn. When
the cylinder pressure gauge pointer stops moving, open the
valve fully.
9. The regulator/flowmeter is adjustable. Set it for the flow rate
recommended for the procedure and process being used
before starting to weld.
1.4 Gun and Cable Installation
The REDI-MIG 240 MIG gun and cable provided with the
machine has a factory fitted 08-1.0mm liner and a 0.9mm
contact tip.
1. Lay the cable out straight.
2. Make sure all pins on the gun cable connector are
aligned with the proper mating sockets on the front
panel gun connector and then join the connectors and
tighten the hand nut on the gun cable connector.
Note: If a gun and cable other than the supplied gun is to
be used, it must conform to standard European-style
connector specifications. See diagram under.
The gun trigger switch must be capable of switching 10
milliamps at 60 volts DC—resistive.
1.5 Output Polarity Connection
The REDI-MIG 255 Integrated is shipped from the factory
connected electrode (+)ve. This is the normal polarity for
gas shielded welding. The gun polarity can be changed by
placing the flexible lead connected to the wire drive
assembly in the wire bay area to the required output stud,
eg. for electrode (-)ve, connect the lead to the (-)ve output
stud.
The REDI-MIG 4D is connected to the REDI-MIG 255
Remote power source via a control/electrode/gas cable
assembly. The electrode cable is connected to the required
output stud inside the tool storage area of the REDI-MIG
255 Remote power source.
The control cable connects to the plug in the tool storage
area of the REDI-MIG 255 Remote power source, below
the output studs.
Connect the work lead to the other output stud.
(See connection diagrams Page 11).
Gas under pressure is explosive. Always keep gas
cylinders in an upright position and always keep chained
to undercarriage or stationary support. Refer “Safety in
Welding and Cutting” - ANSI Standard Z49-1 and WTIA
Technical Note 7 available from the Welding Technology
Institute of Australia.
WARNING
Never stand directly in front of or behind the
regulator/flowmeter when opening the cylinder valve.
Always stand to one side.
WARNING
The gun trigger switch connected to the gun trigger
control cable must be a normally open, momentary switch.
The terminals of the switch must be insulated from the
welding circuit. Improper operation of, or damage to, the
machine might result if this switch is common to an
electrical circuit other than the machine trigger circuit.
CAUTION
Turn the welder power switch off before installing gun and
cable.
WARNING
Turn the welder power switch off before changing polarity.
WARNING
Be sure to keep your face away from the valve outlet when
“cracking” the valve.
WARNING
CYLINDER may explode if
damaged

Page 10 REDI-MIG 255 IMA 598B
2.1 Duty Cycle
The machine is rated at the following duty cycles:
(1) Based on 10 min. time period (i.e., for 60% duty cycle, it is 6
minutes actual welding and 4 minutes with no welding output,
but with the input power remaining on keeping the cooling fan
operative.)
2.2 Control Panel
Note: Burnback control located inside wire bay area (not shown).
a) Power Switch
The mains power switch is incorporated in the “coarse”
output voltage control rotary switch. In the “OFF” position
the input mains power is switched off.
b) Pilot Light
This light illuminates when the input mains power is
switched on.
c) Volts Control
The output voltage is controlled by two rotary switches.
One rotary switch provides four “course” voltage setting as
well as switching the machines power on. The other rotary
switch provides the user with a selection of eight fine
voltage settings. The selection between these two rotary
switches allows the user to select any one of thirty-two
welding voltages.
The approximate weld voltages for the rotary switch
positions are:
d) Wire Feed Speed Control *
Use this control to adjust the speed at which the electrode
wire feeds when welding. This is in effect a current control
as the power source will deliver the current necessary to
melt the wire. The higher the speed, the more current will
be required. Wire feed speed range is approximately 1 to
20 meters/min (40 to 790 inches/min.).
Operation of the gun trigger switches the wire feed motor
on and off, depending upon the trigger mode setting. The
wire feed motor is dynamically braked to minimise wire
overrun after welding has ceased.
Welding voltage is available immediately the gun trigger is
operated. When welding is stopped there is a delay to allow
the electrode to burn back slightly and prevent sticking in
the crater. [See Burnback Control 2.2 e)]
Duty Cycle(1) Amps Volts
30% 255 26.5
60% 180 23
100% 140 21
WARNING
ELECTRIC
SHOCK
can kill
FUMES AND GASES
can be dangerous
WELDING SPARKS can
cause fire or
explosion
ARC RAYS
can burn
• Do not touch electrically live
parts or electrode with skin or
wet clothing.
• Insulate yourself from work and
ground.
•Always wear dry insulating
gloves.
• Keep your head out of fumes.
• Use ventilation or exhaust to
remove fumes from breathing
zone.
• Keep flammable material away.
• Do not weld upon containers
which have held combustibles.
• Wear eye, ear and body
protection.
IMPORTANT SAFETY NOTE: In 2T mode {refer 2.2 (h)}, this
DC Constant Voltage wire welder provides “COLD” electrode
when the gun trigger is not operated. Conversely, the output
terminals are “LIVE” when the gun trigger is “activated” when
pressed in 2T mode, or triggered on in 4T mode.
Section 2 - OPERATING INSTRUCTIONS
Coarse Fine Volts Coarse Fine Volts
A a 12.0 B a 16.0
A b 12.5 B b 16.5
A c 13.0 B c 17.0
A d 13.5 B d 17.5
A e 14.0 B e 18.0
A f 14.5 B f 18.5
A g 15.0 B g 19.0
A h 15.5 B h 19.5
C a 20.0
C b 21.0
C c 22.0
C d 23.0
C e 24.0
C f 25.0
C g 26.0
C h 27.0