Miller MTL-20 Owner's Manual
Millerfi
December
1993
Form:
OM-1568B
Effective
With
Style
No.
KB-8
OWNERS
MANUAL
MTL-20
Torches
U
Read
and
follow
these
instructions
and
all
Give
this
manualtothe
operator.
safety
blocks
carefully.
Have
only
trained
and
qualified
persons
install,
operate,
or
service
this
unit.
Call
your
distributor
if
you
do
not
understand
the
directions.
For
help,
call
your
distributor
or:
MILLER
Electric
Mfg.
Co.,
P.O.
Box
1079,
Appleton,
WI
54912
414-734-9821
Water-Cooled
Torches
For
GTAW
Welding
Rated
At
250
Amperes
100%
Duty
Cycle
Using
Argon
Shielding
Gas
.020
Thru
5/32
in
(0.5
Thru
4.0
mm)
Tungsten
Size
Capacity
Includes
12-1/2
Or
25
ft
(3.8
Or
7.6
m)
Cable
Remote
Contactor
And
Current
Control
Available
Tungsten
Electrode
And
Some
Torch
Parts
Needed
cover
7/93ST-141
476-A
'
1993
MILLER
Electric
MIg.
Co.
PRINTED
IN
USA
1F
MILLERS
TRUE
BLU
ETTM
LIMITED
WARRANTY
Effective
January
1,
1992
(Equipment
with
a
serial
number
preface
of
KC
or
newer)
This
limited
warranty
sapersedes
all
previous
MILLER
warranties
and
is
exclusive
with
no
other
gaarantees
or
warranties
expressed
or
implied.
LIMITED
WARRANTY
Subject
to
the
terms
and
conditions
below,
MILLER
Electric
MIg
Co
.
Appleton.
Wisconsin,
warrants
to
its
original
retail
purchaser
that
new
MILLER
equipment
sold
alter
the
effective
date
01
this
limited
warranty
is
tree
ot
de
tects
in
material
and
workmanship
at
the
time
it
is
skipped
by
MILLER
THIS
WAR.
RANTY
IS
EXPRESSLY
IN
LIEU
OP
ALL
OTHER
WARRANTIES,
EXPRESS
OR
IMPLIED,
INCLUDING
THE
WARRANTIES
OF
MERCHANTAPILITY
AND
FIT
NESS
Within
the
warranty
periods
listed
below
MILLER
will
reoair
or
replace
any
war
ranted
parts
or
components
that
tail
dyetosack
detects
in
material
or
workmanship.
MILLER
mast
be
notitied
in
writing
within
thirty
1301
days
01
sack
defect
or
tailare.
at
which
time
MILLER
will
provide
instructionsonthe
warranty
claim
procedures
to
be
toltawed
MILLER
shall
honor
warranty
claims
en
warranted
equipment
listed
belowinthe
eeent
01
sackadilute
within
the
warranty
time
periods
All
warranty
time
periods
start
on
the
date
that
the
equipment
was
delivered
to
the
original
retail
parchaser.
or
one
year
user
the
equipment
is
sent
to
the
distributor
5
Years
Parts
-
3
Yeats Labor
Original
main
power
rectiliers
2 3
YearsParts
and
Labor
Transformer/Rectifier
Power
Searces
*
Plasma
Arc
Catting
Power
Sources
*
Semi-Automatic
and
Automatic
Wire
Feeders
Robots
32YearsParts
and
Labor
Engine
Driven
Welding
Generators
(NOTE
Engines
are
warranted
separately
by
the
engine
manufacturer
for
a
period
01
two
years.(
*
Air
Compressors
1
Year
Parts
and
Labor
Motor
Driven
Guns
*
Process
Controllers
Water
Coolant
Systems
HP
Units
Grids
Spot
Welders
*
Load
Banks
SOX
Transformers
Running
Gearrrrailers
Field
Options
(NOTE
Field
options
are
covered
ander
Trae
BluenM
far
the
remaining
warranty
period
of
the
predact
they
are
installed
in,
or
for
a
minimam
of
one
year
-
whichever
is
greater
I
6
Months
Batreries
90
Days
Parts
and
Labor
MIG
Gsns/TIG
Torches
Plasma
Catting
Torches
Remote
Controls
*
Accessory
Kits
Replacement
Pans
MILLER
S
Trae
Efae
Limited
Watranty
shall
net
apply
to.
I
Items
tarnishedbyMILLER.
bat
manafactared
by
others.
sack
as
engines
er
trade
accessories
These
items
are
covered
by
the
manafecturers
warranty,
it
any
2
Consumable
components,
sack
as
contact
tips.
catting
nozzles,
centacters
and
relays
or
parts
that
tail
dye
to
normal
wear
3
Equipment
that
has
been
modrfied
by
any
party
ether
than
MILLER.
or
equip
ment
that
has
been
improperly
installed,
improperly
operated
or
misased
based
apon
indastry
standards.
or
eqaipment
which
has
net
had
reasonable
and
necessary
maintenance.
or
equipment
whick
has
been
axed
tsr
operation
outsideofthe
specifications
br
the
equipment
MILLER
PRODUCTS
ARE
INTENDED
FOR
PURCHASE
AND
USE
BY
COMMER
CIALINDUSTRIAL
USERS
AND
PERSONS
TRAINED
AND
EXPERIENCED
IN
THE
USE
AND
MAINTENANCE
OP
WELDING
EQUIPMENT.
In
the
event
of
a
warranty
claim
coveredbythis
warranty,
the
exclusixe
remedies
shall
be.atMILLER
S
option
(11
repair.
or
(2(
replacement,
or,
where
authorized
in
writing
by
MtLLER
in
appropriate
cases.
(3)
the
reasonable
cost
of
repairer
replace
ment
at
an
authorized
MILLER
sernrce
station.
or
(4)
payment
of
or
credit
br
the
pur
chase
price
(less
reasonable
deprecrutrOn
based
upon
actual
ase(
apes
return
eb
the
goods
at
customers
risk
and
espense.
MILLERS
option
01
repair
or
replacement
will
be
P0
B
Factory
at
Appleton,
Wisconsin,
or
F
0
B
at
a
MILLgR
authorized
ser
vice
facility
us
determined
by
MILLER.
Therefore
no
compensation
or
reimburse
ment
for
trunsportatiee
costs
of
any
kind
will
be
allowed,
TO
THE
EXTENT
PERMITTED
BY
LAW.
THE
REMEDIES
PROVIDED
HEREIN
ARE
THE
SOLE
AND
EXCLUSIVE
REMEDIES
IN
NO
EVENT
SHALL
MILLER
BE
LIABLE
FOR
DIRECT
INDIRECT,
SPECIAL.
INCIDENTAL
OR
CONSEQUENTIAL
DAMAGES
INCLUDING
LOSS
OF
PROFIT),
WHETHER
BASED
ON
CON
TRACT TORT
OR
ANY
OTHER
LEGAL
THEORY
ANY
EXPRESS
WARRANTY
NOT
PROVIDED
HEREIN
ANO
ANY
IMPLIED
WAR
RANTY
GUARANTY
OR
REPRESENTATION
AS
TO
PERFORMANCE
AND
ANY
REMEDY
FOR
BREACH
OF
CONTRACT
TORT
OR
ANY
OTHER
LEGAL
THEORY
WHICH.
BUT
FOR
THIS
PROVISION.
MIGHT
ARISE
BY
IMPLICATION.
OPERATION
OF
LAW,
CUSTOM
OF
TRADE
OR
COURSE
OP
DEALING.
IN
CLUDING
ANY
IMPLIED
WARRANTY
OF
MERCHANTABILITY
OR
PITNESS
FOR
PARTICULAR
PURPOSE,
WITH
RESPECT
TO
ANY
AND
ALL
EQUIPMENT
FURNISHED
BY
MILLER
IS
EXCLUDED
AND
DISCLAIMED
BY
MILLER
Some
states
in
the
U
S
A
do
not
allow
limitations
01
how
long
an
implied
warranty
lasts,
or
the
exclusion
of
incidental,
indirect,
special
or
consequential
damages,
so
the
above
limitationorexclusion
may
not
apply
10
you
This
warranty
pronides
spe
citic
legal
rights,
and
sther
rights
may
be
aeuilable,
but
may
eury
trem
statetostate.
In
Canada.
legislation
in
some
proxinces
proeides
or
certain
additional
warranties
or
remedies
other
thanasstaled
herein,
and
to
the
extent
that
they
may
not
be
waived,
the
limitations
and
exclusions
set
out
aboxe
may
net
apply.
This
Limited
Warranty
pieuides
specific
legal
rights.
and
other
rights
may
be
uxailuble.
but
map
vary
Irom
province
to
proxince.
:JU
B,
IF
RECEIVING-HANDLING
Before
unpacking
equipment,
check
carton
for
any
damage
that
may
have
occurred
duhng
shipment.
File
any
claims
for
loss
or
damage
with
the
delivering
carrier.
Asststance
for
filing
or
settling
claims
may
be
obtained
from
distributor
and/or
equipment
manufacturers
Transportation
Department.
When
requesting
information
about
this
equipment,
always
provide
Model
Designation
and
Serial
or
Style
Number
Use
the
following
spaces
to
record
Model
Designation
and
Serial
or
Style
Number
of
your
unit.
The
information
is
located
on
the
rating
label
or
nameplate.
Model
__________
Serial
or
Style
No.
DateofPurchase
miller
9/93
SAFETY
PRECAUTIONS
FOR
GTAW
TORCHES
Always
wear
dry
insulating
gloves.
Insulate
yourself
from
work
and
ground.
Do
not
touch
live
electrode
or
electrical
parts.
Repair
or
replace
worn,
damaged,
or
cracked
torchorcable
insulation.
Turn
off
welding
power
source
before
changing
tungsten
electrodeortorch
parts.
Keep
all
covers
and
handle
securely
in
ARC
RAYS
can
burn
eyes
and
skin.
Wear
welding
helmet
with
correct
shade
of
filter.
Wear
correct
eye
and
body
protection.
Cover
exposed
skin.
FUMES
AND
GASES
can
be
hazardous
to
your
health.
Keep
your
head
out
of
the
fumes.
Ventilate
area,
or
use
breathing
device.
Read
Material
Safety
Data
Sheets
(MSDSs)
and
manufacturers
instructions
for
material
used.
WELDING
can
cause
fire
or
explosion.
1.
Do
not
weld
near
flammable
material.
2.
Do
not
weldonclosed
containers.
3.
Watch
for
fire;
keep
extinguisher
nearby.
HOT
SURFACES
can
burn
skin.
1.
Allow
torch
to
cool
before
touching.
2.
Do
not
touch
hot
metal.
3.
Protect
hot
metal
from
contact
by
others.
NOISE
can
damage
hearing;
SOME
APPLICATIONS,
SUCH
AS
PULSING,
are
noisy.
1.
Check
for
noise
level
limits
exceeding
those
specified
by
OSHA.
2.
Use
approved
ear
plugs
or
ear
muffsifnoise
level
is
high.
3.
Warn
others
nearby
about
noise
hazard.
EMF
INFORMATION
a
WARNING
GTAW
WELDING
can
be
hazardous.
PROTECT
YOURSELF
AND
OTHERS
FROM
POSSIBLE
SERIOUS
INJURY
OR
DEATH.
KEEP
CHILDREN
AWAY.
PACEMAKER
WEARERS
KEEP
AWAY
UNTIL
CONSULTING
YOUR
DOCTOR.
In
welding,
as
in
most
jobs,
exposure
to
certain
hazards
occurs.
Welding
is
safe
when
precautions
are
taken.
The
safety
information
given
below
is
only
a
summary
of
the
more
complete
safety
information
found
in
the
welding
power
source
Owners
Manual.
Read
and
follow
all
safety
precautions.
HAVE
ALL
INSTALLATION,
OPERATION,
MAINTENANCE,
AND
QUALIFIED
PEOPLE.
ELECTRIC
SHOCK
can
kill.
REPAIR
WORK
PERFORMED
ONLY
BY
A
NOTE
D~
Considerations
About
Welding
And
The
EffectsOfLow
Frequency
Electric
And
Magnetic
Fields
The
following
is
a
quotation
from
the
General
Conclusions
Section
of
the
U.S.
Congress,
Office
of
Technology
Assessment,
Biological
Effects of
Power
Frequency
Electric
&
Magnetic
Fields
Backg
round
Paper,
OTA-BP-E-53
(Washington,
DC:
U.S.
Government
Printing
Office,
May
1989):
...
there
is
now
a
very
large
volume
of scientific
findings
based
on
experiments
at
the
cellular
level
and
from
studies
with
animals
and
people
which
clearly
establish
that
low
frequency
magnetic
fields
can
interact
with,
and
produce
changes
in,
biological
systems.
While
most
of
this
work
is
of
very
high
quality,
the
results
are
complex.
Current
scientific
understanding
does
not
yet
allow
us
to
interpret
the
evidence
in
a
single
coherent
framework.
Even
more
frustrating,
it
does
not
yet
allow
us
to
draw
definite
conclusions
about
questions
of
possible
risk
or
to
offer
clear
science-based
advice
on
strategies
to
minimize
or
avoid
potential
risks.
To
reduce
magnetic
fields
in
the
workplace,
use
the
following
procedures:
1.
Keep
cables
close
togetherbytwisting
or
taping
them.
2.
Arrange
cables
to
one
side
and
away
from
the
operator.
3.
Do
not
coil
or
drape
cables
around
the
body.
4.
Keep
welding
power
source
and
cablesasfar
away
as
practical.
5.
Connect
work
clamp
to
workpiece
as
close
to
the
weld
as
possible.
About
Pacemakers:
The
above
procedures
are
among
those
also
normally
recommended
for
pacemaker
wearers.
Consult
your
doctor
for
complete
information.
modlO.1
4/93
sr6
7/93
SECTION
1
-
SAFETY
INFORMATION
Read
all
safety
messages
throughout
this
manual.
Obey
all
safety
messages
to
avoid
injury.
Learn
the
meaning
of
WARNING
and
CAUTION.
Ampere
Rating
At
100%
Duty
Cycle
DCEN,
ACHF
Cooling
Method
Coolant
Flow
Rate
Tungsten
Size
Capacity
Torch
Body
Dimensions
And
Weight
Options
And
Accessories
Total
Weight
Figure
1-1.
Safety
Information
SECTION
2-
SPECIFICATIONS
Table
2-1.
Welding
Torch
modl,1
2193
1
2
2
a
CAUTION
!
:
3
__________
_____
=fl~S~9I~,ngPOw&Of0r~11
~
________________________
5
6
a
WARNING
7H
NOTE
~
READ
SAFETY
BLOCKS
at
start
of
Section
3-1
before
proceeding.
1
Safety
Alert
Symbol
2
Signal
Word
WARNING
means
possible
death
or
serious
injury
can
happen.
CAUTION
means
possible
minor
injury
or
equipment
damage
can
happen.
3
Statement
Of
Hazard
And
Result
4
Safety
Instructions
To
Avoid
Hazard
5
Hazard
Symbol
(If
Available)
6
Safety
Banner
Read
safety
blocks
for
each
sym
bol
shown.
7
NOTE
Special
instructions
for
best
oper
ation
not
related
to
safety.
Turn
Off
switch
when
using
high
frequency.
Specification
Model
Description
Description
MT:
Miller
Torch;
L:
Flex
Lok;
20:
250
Ampere
Rating;
12:
12-1/2
ft(3.8
m)
Cable;
25:25
ft(7.6
m)
Cable
Example:
MTL-20-12
Miller
Torch;
Flex
Lok;
250
Ampere
Rating;
12-1/2
ft
(3.8
m)
Cable
250
Amperes
Using
Argon
Gas
Water
Cooling
1
qt/min
(0.94
11mm)
.020
Thru
5/32
in
(0.5
Thru
4.0
mm)
Length:
9-1/2
in
(241
mm);
Handle
Diameter:
3/4
in
(19
mm);
Weight:
5
oz
(140
g)
See
Rear
Cover
12-1/2
ft
(3.8
m)
Cable
25
ft
(7.6
m)
Cable
Net:
2
lb
(0.9
kg);
Ship:
2
lb
(0.9
kg)
Net:
3
lb
(1.4
kg);
Ship:
3
lb
(1.4
kg)
OM-1568
Page
1
2-1.
Duty
Cycle
a
CAUTION
WELDING
LONGER
THAN
RATED
DUTY
CYCLE
can
damage
torch
and
void
warranty.
Do
not
weld
at
rated
load
longer
than
shown
below.
3-1.
Required
Torch
Parts
And
Torch
Assembly
Installing
Tungsten
Loosen
~ia
Obtain
the
following
parts
(see
Section
6):
1
Tungsten
Electrode
(See
Section
5)
-~
2
Cup
-~
3
Collet
Body
4
Standard
Collet
5
Reverse
Collet
Reverse
collet
improves
electrical
contact
of
tungsten
electrode.
6
Power
Cable
Adapter
Assembling
Torch
Body
7
Flex-Lok
Head
8
Heat
Shield
9
Backcap
(Long
Backcap
Shown)
10
0-Ring
Installing
Tungsten
To
adjust
tungsten
position,
loosen
backcap.
Keep
connections
tight.
Replace
cup,
heat
shield,
backcap,
and
0-rings
if
cracked.
wlwacnB.r
8/93
0
Definition
Duty
Cycle
is
percentage
of
10
10
minutes
that
torch
can
weld
at
rated
load
without
overheating.
Minutes
100%
Duty
Cycle
At
250
Amperes
Using
Argon
Gas
G~
Continuous
Welding
sbl58/93
Figure
2-1.
Duty
Cycle
SECTION
3-INSTALLATION
&
OPERATION
Required
Torch
Parts
Assembling
Torch
Parts
2
-4
5
Tighten
Figure
3-1.
Required
Torch
Parts
And
Torch
Assembly
~ef.
ST-800
454
OM-1568
Page
2
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