cover 8/92 − ST-148 531-A PRINTED IN USA
Read and follow these instructions and all
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.
Give this manual to the operator.
For help, call your distributor
or: MILLER ELECTRIC Mfg. Co., P.O. Box
1079, Appleton, WI 54912 414-734-9821
OWNER’S
MANUAL
September 1992 Form: OM-1029
Effective With Style No. KC38
GA-21C & GA-21CM
OM-1029 − 9/92
TABLE OF CONTENTS
SECTION 1 − SAFETY SIGNAL WORDS 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 2 − SPECIFICATIONS
2-1. Duty Cycle 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 3 − INSTALLING THE GUN 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 4 − OPERATING THE GUN 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 5 − MAINTENANCE
5-1. Inspection And Upkeep 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-2. Replacing Gun Contact Tube 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-3. Cleaning Or Replacing Gun Liner 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 6 − PARTS LIST
Figure 6-1. Exploded View Of Gun (GA-21CM Model Illustrated) 7. . . . . . . . . . . . . . . . . . . . . . . . . . . .
OM-1029 Page 1
SECTION 1 − SAFETY SIGNAL WORDS
mod1.1 9/91
The following safety alert symbol and signal words are used throughout this manual to call attention to and identify
different levels of hazard and special instructions.
WARNING
WARNING statements identify procedures or practices which must be followed to avoid serious personal
injury or loss of life.
CAUTION
CAUTION statements identify procedures or practices which must be followed to avoid minor personal
injury or damage to this equipment.
IMPORTANT: statements identify special instructions necessary for the most efficient operation of this equipment.
SECTION 2 − SPECIFICATIONS
Table 2-1. Specifications
Specifications Description
Rated Output 200 Amperes Using CO
2
Shielding Gas
Duty Cycle 100%
Cooling Method Air
Wire Diameter .023 to .045 in. (0.6 to 1.1 mm) Hard Or Flux-Cored Wires
Cable Length 12-1/2 ft. (3.8 m)
15 ft. (4.5 m)
Weight 12-1/2 ft. Gun: Net: 4.9 lbs. (2.2 kg); Ship 7.4 lbs. (3.4 kg)
15 ft. Gun: Net: 5.2 lbs. (2.4 kg); Ship 7.7 lbs. (3.5 kg)
2-1. Duty Cycle
Duty cycle is the percentage of a ten minute period that the gun can be operated using CO
2
shielding gas without
causing damage or overheating. This gun is rated at 100% duty cycle allowing continuous operation at rated output.
CAUTION
USING GUN BEYOND DUTY CYCLE RATING can damage gun.
• Do not use gun beyond rated amperage when using CO
2
shielding gas.
• Use gun at 50% duty cycle when using mixed shielding gas.
wfwarn8.1 10/91
OM-1029 Page 2
SECTION 3 − INSTALLING THE GUN
WARNING
ELECTRIC SHOCK can kill.
• Do not touch live electrical parts.
• Turn OFF welding power source, and disconnect
input power before inspecting, maintaining, or
servicing.
HOT PARTS can cause severe burns.
• Allow cooling period before maintaining or servicing.
MOVING PARTS can cause injury.
• Keep away from moving parts.
• Keep away from pinch points such as drive rolls.
swarn8.2* 10/91
12
3
4
5
6
1 Gun Opening
2 Gun Trigger Receptacle
3 Drive Assembly
4 Gun Securing Knob
5 Gun End
Loosen securing knob. Insert gun
end through opening until it bottoms
against drive assembly. Tighten
knob.
6 Gun Trigger Plug
Insert into receptacle, and tighten
threaded collar.
Close door.
Ref. ST- 150 256-B / Ref. SD-147 592
Figure 3-1. Gun And Trigger Connections
OM-1029 Page 3
SECTION 4 − OPERATING THE GUN
WARNING
ELECTRIC SHOCK can kill.
• Always wear dry insulating gloves.
• Insulate yourself from work and ground.
• Do not touch live electrical parts.
• Keep all panels and covers securely in place.
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.
• Do not weld near flammable material.
• Watch for fire; keep extinguisher nearby.
• Do not locate unit over combustible surfaces.
• Do not weld on closed containers.
• Allow work and equipment to cool before handling.
ARC RAYS can burn eyes and skin;
NOISE can damage hearing.
• Wear welding helmet with correct shade of filter.
• Wear correct eye, ear, and body protection.
MOVING PARTS can cause injury.
• Keep away from pinch points such as drive rolls.
• Keep all doors, panels, covers, and guards closed
and securely in place.
MAGNETIC FIELDS FROM HIGH CUR-
RENTS can affect pacemaker operation.
• Pacemaker wearers keep away.
• Wearers should consult their doctor before going
near arc welding, gouging, or spot welding opera-
tions.
See Safety Rules at beginning of wire feeder or welding
power source Owner’s Manual for basic welding safety
information.
swarn6.2* 10/91
1 Gun Trigger
When pressed, wire feeds and is
energized, and gas flows.
2 Gun Decrease (Microproces-
sor Models)
Push down to decrease selected
value. For dual scheduling, push
and release to activate Switch B
program.
3 Gun Increase (Microproces-
sor Models)
Push up to increase selected value.
For dual scheduling, push and re-
lease to activate Switch A program.
Ref. ST-148 531
1
2
3
Figure 4-1. Gun Switches
OM-1029 Page 4
SECTION 5 − MAINTENANCE
WARNING
ELECTRIC SHOCK can kill.
• Do not touch live electrical parts.
• Turn OFF welding power source, and disconnect
input power before inspecting, maintaining, or
servicing.
HOT PARTS can cause severe burns.
• Allow cooling period before maintaining or servicing.
MOVING PARTS can cause injury.
• Keep away from moving parts.
• Keep away from pinch points such as drive rolls.
Maintenance to be performed only by qualified persons.
swarn8.2 10/91
5-1. Inspection And Upkeep
READ SAFETY BLOCKS at start of
Section 5 before proceeding.
WARNING
Turn OFF all power before main-
taining.
3 Months
Replace
Unreadable
Labels
Clean
And
Tighten
Weld
Terminals
− −
3 Months
See
Section
6
Tape Or
Replace
Cracked
Weld
Cable
− −
Control Cord
Gas Hose Gun Cable
− −
Replace
Cracked
Parts
Blow Out
Gun
Casing
Each Spool Of Wire
Clean
Drive
Rolls
− −
− −
Figure 5-1. Maintenance
5-2. Replacing Gun Contact Tube
READ SAFETY BLOCKS at start of
Section 5 before proceeding.
WARNING
Turn OFF unit.
1 Nozzle
Cut off welding wire at contact tube.
Remove nozzle
2 Contact Tube
Remove contact tube and install
new contact tube. Reinstall nozzle.
Ref. ST-150 255
1
2
Figure 5-2. Replacing Contact Tube
OM-1029 Page 5
5-3. Cleaning Or Replacing Gun Liner
READ SAFETY BLOCKS at start of Section 5 before proceeding.
WARNING
CAUTION
FLYING METAL CHIPS AND DIRT can cause injury and damage equipment.
• Point gun away from people and in a safe direction when blowing out with compressed air.
Turn OFF unit and disconnect input
power.
1 Wire Spool
Cut welding wire off at contact tube.
Retract wire onto spool and secure.
2 Gun Securing Knob
Loosen knob and remove gun and
trigger plug.
3 Nozzle
4 Contact Tube
5 Contact Tube Adapter
6 Setscrew
7 Wire Outlet Guide
Disassemble gun as shown.
8 Liner
Pull liner from this end. Blow gun
casing out with compressed air.
Ref. ST-150 256-B / ST-145 478-C
Tools Needed:
3/8 in.
12
3
4
5
7
8
6
Figure 5-3. Removing Gun Liner
OM-1029 Page 6
Turn OFF unit and disconnect input
power.
1 Liner
Insert new liner into gun casing.
The liner end covered with clear
tubing goes to the head tube.
2 Wire Outlet Guide
Reinstall so that 1/8 in. (3 mm) of lin-
er sticks out. Hand tighten guide,
and then tighten two full turns more.
3 Head Tube
Cut liner off so that 1/2 in. (13 mm)
sticks out of head tube. Trim clear
tubing off 1/4 in. (6.3 mm) from end
of liner.
4 Setscrew
Tighten setscrew to secure liner in
head tube. Overtightening set-
screw crushes liner and causes
wire feed problems.
5 Contact Tube Adapter
6 Contact Tube
7 Nozzle
Reassemble gun.
Reinstall gun (see Section 3).
Thread welding wire. Close door.
Tools Needed:
3/8 in.
ST-150 438-A
1
2
3
4
5
6
Clear
Tubing
7
Figure 5-4. Installing Gun Liner
SECTION 6 − PARTS LIST
Quantity
Description
Part
No.
Item
No.
Figure 6-1. Exploded View Of Gun
Model
GA-21C GA-21CM
1 145 213 ACTUATOR, inc/dec 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 152 669 KIT, head tube (consisting of) 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 081 960 RING, retaining ext .500 shaft x .035thk 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 086 281 HOSE, nprn .500 ID x .687 OD x 3.375 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
154 731 SCREW, set stl sch 10-24 x .312 cup point 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 082 063 NUT, conduit .875-20 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6 082 241 INSULATOR, nozzle 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7 146 425 ADAPTER, tube contact .030 − .045 wire 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7 ♦146 426 ADAPTER, tube contact .023 wire 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 071 825 TUBE, cont scr .030 wire x 1.312 2 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 054 202 TUBE, cont scr .030 − .035 wire x 1.312 2 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 ♦087 300 TUBE, cont scr .023 wire x 1.312 3 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8 ♦054 201 TUBE, cont scr .045 wire x 1.312 3 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9 149 146 NOZZLE, scr type .625 orf x 2.250 lg 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10 145 377 SWITCH BLOCK 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11 144 344 CABLE/CONDUIT, 12-1/2ft (consisting of) 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11 145 375 CABLE/CONDUIT, 12-1/2ft (consisting of) 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11 +♦149 272 CABLE/CONDUIT, 15ft 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11 +♦149 275 CABLE/CONDUIT, 15ft 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12 089 902 TERMINAL, rcpt skt 20-24 wire insulated 2 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13 079 974 O-RING, .500 ID x .103CS rbr 2 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
14 106 590 O-RING, .375 ID x .103CS nitrile 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
15 120 164 TRIGGER, switch assembly 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16 115 843 SCREW, set stl sch 10-24 x .312 cup point 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
OM-1029 Page 7
1
ST-148 347-D
2
3
4
5
6
7
8
9
10 11
12
13
14
15
16
17
18
19
Includes
Items 13 & 14
20
21
22
19
23
24
25
26
18
27
Figure 6-1. Exploded View Of Gun (GA-21CM Model Illustrated)
OM-1029 Page 8
Quantity
Description
Part
No.
Item
No.
Figure 6-1. Exploded View Of Gun (Continued)
Model
GA-21C GA-21CM
17 149 927 HANDLE, gun (consisting of) 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17 149 928 HANDLE, gun (consisting of) 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 081 960 RING, retaining ext .500 shaft x .035thk 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 086 281 HOSE, nprn .500 ID x .687 OD x 3.375 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18 128 758 RING, locking 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19 091 602 STRAIN RELIEF, cable (consisting of) 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
20 049 312 RING, locking handle 2 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21 ♦149 278 KIT, liner monocoil .023/.025 wire x 12-1/2ft (consisting of) 1 1. . . . . . . . . . . . . . . . . . . . . . . . . .
22 146 797 LINER, monocoil .025 wire x 12-1/2ft 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23 128 769 GUIDE, wire outlet .023 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21 149 279 KIT, liner monocoil .030/.035 wire x 12-1/2ft (consisting of) 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . .
22 146 798 LINER, monocoil .030 − .035 wire x 12-1/2ft 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23 120 995 GUIDE, wire outlet .030 − .045 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21 ♦149 280 KIT, liner monocoil .045 wire x 12-1/2ft (consisting of) 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22 146 079 LINER, monocoil .045 wire x 12-1/2ft 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23 120 995 GUIDE, wire outlet .030 − .045 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21 ♦149 281 KIT, liner monocoil .023/.025 wire x 15ft (consisting of) 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22 149 271 LINER, monocoil .025 wire x 15ft 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23 128 769 GUIDE, wire outlet .023 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21 ♦149 282 KIT, liner monocoil .030/.035 wire x 15ft (consisting of) 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22 149 270 LINER, monocoil .030/.035 wire x 15ft 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23 120 995 GUIDE, wire outlet .030-.045 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21 ♦149 283 KIT, liner monocoil .045 wire x 15ft (consisting of) 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22 149 269 LINER, monocoil .045 wire x 15ft 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23 120 995 GUIDE, wire outlet .030-.045 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
24 079 878 HOUSING PLUG & PINS, (consisting of) 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
079 535 CONN, circ pin pushin 18-14ga Amp 66359-6 4 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25 048 834 CONN, circ clamp str rlf Amp 206062-4 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26 604 525 CABLE, port No. 18 2/c (order by ft 2ft. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26 053 212 CABLE, port No. 18 4/c (order by ft) 2ft. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27 112 884 STRAIN RELIEF, extension gun end 1 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
♦OPTIONAL
BE SURE TO PROVIDE MODEL AND SERIAL NUMBER WHEN ORDERING REPLACEMENT PARTS.
-
1
-
2
-
3
-
4
-
5
-
6
-
7
-
8
-
9
-
10
-
11
Miller GA-21C Owner's manual
- Category
- Welding System
- Type
- Owner's manual
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