Miller MTL-20 Torches User manual

Millerfi
December
1993
Form:
OM-1568B
Effective
With
Style
No.
KB-8
OWNERS
MANUAL
MTL-20
Torches
U
Read and follow
these
instructions and all

Give
this
manual
to
the
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
7/93

ST-141
476-A
'
1993
MILLER
Electric
MIg.
Co.
PRINTED
IN
USA

1F
MILLERS
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
dye
to
sack
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
instructions
on
the
warranty
claim
procedures
to
be
toltawed
MILLER
shall honor
warranty
claims
en
warranted
equipment
listed below
in
the
eeent
01 sack
a
dilute
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
Years

Parts
and
Labor

Transformer/Rectifier Power Searces
*
Plasma
Arc
Catting
Power
Sources
*
Semi-Automatic
and
Automatic
Wire
Feeders

Robots
3 2 Years

Parts 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 tarnished
by
MILLER.
bat
manafactared
by
others.
sack
as
engines
er
trade
accessories
These
items
are
covered
by
the
manafecturers
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
outside
of
the
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 covered
by
this
warranty,
the
exclusixe
remedies
shall
be.
at
MILLER
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
customers risk and
espense.
MILLERS
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
limitation
or
exclusion
may
not
apply
10
you
This
warranty
pronides
spe
citic
legal
rights,
and
sther
rights
may
be
aeuilable,
but
may eury
trem
state to state.
In
Canada.
legislation
in
some
proxinces
proeides
or
certain
additional
warranties
or
remedies
other
than
as
staled
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.
:JU
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
manufacturers
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.
Date of Purchase
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
torch
or
cable insulation.
Turn off
welding
power
source
before
changing
tungsten
electrode
or
torch
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
manufacturers
instructions
for material
used.
WELDING
can cause
fire
or
explosion.
1.
Do
not
weld
near
flammable
material.
2.
Do
not
weld
on
closed
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
muffs
if
noise
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
Owners
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
Effects
Of
Low
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
together by twisting
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
cables
as
far
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
sbl
5
8/93
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

3-2.
Adjusting
Flex-Lok
Head
£~
CAUTION
TOOLS
can
damage
torch.

Do
not
use
hand
tools
to
adjust
torch
flex-bk head.
Hold
stem
and
turn
head
one
full
turn.
1
Stem
2 Head
Turn head and
stem to
desired
angle.
Figure
3-2.
Adjusting
Flex-Lok
Head
Ret. ST-14~
477-B
I
Hold
stem
and
turn
head
until
tight.
OM-1568
Page
3

3-3.
Connecting
Torch
_~\
~
READ SAFETY
BLOCKS at
beginning
of
manual before
proceeding.
BUILDUP
OF SHIELDING GAS
can
harm health
or
kill.

Shut
off
shielding
gas
supply
when
not
in
use.
warnl.1
9/91
Turn
Ott
welding
power
source,
and disconnect
input
power
before
installing
torch.
Obtain
the
following
hoses:
1
Gas
Hose With
5/8.18
Right-
Hand
Fittings
2
Coolant
Hose With 5/8-18
Left-Hand
Fitting
Connections:
3
Regulator/Flowmeter
4
Gas
Cylinder
5
Welding
Power
Source
6
Gas-In
Hose
7
Gas Valve
Valve controls
gas
preflow
and
postflow.
Preflow
aids
arc
starting.
Preflow
and
postflow
prevent
elec
trode from
forming
a
black
surface
(oxidizing).
After
welding,
allow
10 seconds
of
gas
postflow
for
every
100
am
peres
of weld
current.
8
Coolant-In
Hose
9
Power
Cable/Coolant-Out
Hose
10
Power
Cable
Adapter
Connect
hoses
to
adapter
before
connecting
adapter
to
weld
output
terminal.
11
Cooling
System
Mix
coolant
according
to
cooling
system
owners
manual.
Torch
is rated
at
1
qtimin
(0.94U
mm)
coolant
flow
rate.
Maintain
proper
flow
rate at
all
times.
12
Input
Power
Plug
13
Grounded
AC
Receptacle
Connect
plug
to
proper
receptacle.
14
Work
Clamp
Connect
work
clamp
to a
clean,
paint-free
location
on
workpiece,
as
close
to
weld
area as
possible.
Use wire brush
or
sandpaper
to
clean
metal
at
weld
joint
area.
~
5/8,
7/8
in
Ref.
$T-800
454
Figure
3-3.
Connecting
Torch
If
applicable,
install
high-frequency
unit.
14
11
Tools Needed:
OM-1568
Page
4

3-4.
Coolant Guidelines
__
a
WARNING
ELECTRIC
SHOCK
can
kill;
MOVING
PARTS
can
cause
serious
injury.

Do
not
touch live
electrical
parts.

Keep
away
from
moving
parts.

Disconnect
input
power
plug
from
receptacle
before
cleaning
system components.
FAILURE
TO
PROPERLY
MAINTAIN
COOLANT SYSTEM
can
cause
damage
to
the coolant
system
and
torch/gun.

Circulate
and
flush
clear
water
through
entire
system,
and
replace
coolant
every
six
months.
INCORRECT
COOLANT
will
damage
torch and
cooling
system.

Use
plain
distilled
or
deionized
water,
or
use
high
quality
tap
water.

In
freezing
temperatures
use
only
a
mix
of
pure
ethylene glycol
and distilled
or
deionized
water
such
as
MILLER
coolant
Part
No.
128 705
or
equivalent.
DO NOT
USE
AUTOMOTIVE
ANTIFREEZE.
Follow these
guidelines
to
de
crease
corrosion
in
torch and cool
ing
system.
Material
in
contact
with
coolant
can
only
be
brass,
copper,
silver
solder,
300
Series
stainless
steel,
or
plastic.
1
Coolant
See table for
coolant mixture
need
ed for
operating
temperature.
2
Coolant
System
Tank
Keep
coolant
level full.
Length
of
coolant
hoses
affects
amount
of
coolant needed in
unit.
3
Changing
Coolant
Change
coolant
when
dirty
or
every
6 months.
4
Connections
Keep
connections
tight.
Make
elec
trical
connections
with
connectors
of
the
same
metal.
Figure
3-4. Coolant
Guidelines
2
o
00
Filling
I
I
Tighten
Connections
4
3
S-0760
OM-1568
Page
5

SECTION
4-
MAINTENANCE
&
TROUBLESHOOTING
Iz$~J ~
READ
SAFETY
BLOCKS
at
beginning
of
manual
before
proceeding.
Table
4-1.
Troubleshooting
N
OT
E
~
Before
using
trouble
shooting
table,
check selection
and
preparation
of
tungsten
electrode
according
to Section
5.
Trouble
Remedy
Lack of
high frequency:
difficulty
in
establishing

-~
Check
cables
and
torch
for cracks
or
bad
connections. Be
sure
that
torch
cables
arc.
are
not
close
to
any
grounded
metal.
Repair
or
replace
necessary
parts.
Check
welding power
source
high
frequency
control,
and
if
necessary,
check
and
adjust spark
gaps.
Wandering
arc

poor
control
of
direction of
arc.
 
...~
Reduce
gas
flow
rate
according
to
welding
power
source
Owners
Manual.
Tungsten
electrode
oxidizing
and
not
remaining



bright
after
conclusion of
weld.
Shield
weld
zone
from
drafts. Check
and
tighten
all
gas
fittings.
Increase
postflow
time
according
to
welding
power
source
Owners
Manual.
Check
gas
valve.
Torch
and/or
power
cable/coolant-out
hose
 
-~
Check
cooling
system
operation.
Make
sure
coolant
hoses
are
clear of
obstruc
overheats.
tions
and
are
not
pinched.
Turn
Off
all
power
before
maintaining.
Coolant
Hose
(Also Keep
Hose
Clean)
Torch Cable
Figure
4-1.
Maintenance Schedule
OM-1568
Page
6