MILLER S-74S (02) PDF MANUAL

Touching live electrical parts can cause fatal shocks or severe burns. The electrode and work circuit, wire, wire reel, drive roll housing, and all metal parts touching the welding wire are electrically live whenever the output is on. The input power circuit and internal circuits are also live when power is on.

Do not touch live electrical parts.

Wear dry, hole-free insulating gloves and body protection.

Insulate yourself from work and ground using dry insulating mats or covers big enough to prevent any physical contact with the work or ground.

Do not use AC output in damp areas, if movement is confined, or if there is a danger of falling. Use AC output ONLY if required for the welding process.

If AC output is required, use remote output control if present on unit.

Disconnect input power or stop engine before installing or servicing this equipment.

Properly install and ground this equipment according to its Owner’s Manual and national, state, and local codes.

Always verify the supply ground.

When making input connections, attach proper grounding conductor first.

Frequently inspect input power cord for damage or bare wiring – replace cord immediately if damaged.

Turn off all equipment when not in use.

Do not use worn, damaged, undersized, or poorly spliced cables.

Do not drape cables over your body.

If earth grounding of the workpiece is required, ground it directly with a separate cable.

Do not touch electrode if you are in contact with the work, ground, or another electrode from a different machine.

Use only well-maintained equipment. Repair or replace damaged parts at once.

Keep all panels and covers securely in place.

Clamp work cable with good metal-to-metal contact to workpiece or worktable as near the weld as practical.

Insulate work clamp when not connected to workpiece to prevent contact with any metal object.

Welding produces fumes and gases. Breathing these fumes and gases can be hazardous to your health.

Keep your head out of the fumes. Do not breathe the fumes.

If inside, ventilate the area and/or use local forced ventilation at the arc to remove welding fumes and gases.

If ventilation is poor, wear an approved air-supplied respirator.

Read and understand the Material Safety Data Sheets (MSDSs) and the manufacturer’s instructions for metals, consumables, coatings, cleaners, and degreasers.

Work in a confined space only if it is well ventilated, or while wearing an air-supplied respirator. Always have a trained watchperson nearby.

Do not weld in locations near degreasing, cleaning, or spraying operations.

Do not weld on coated metals, such as galvanized, lead, or cadmium plated steel, unless the coating is removed from the weld area, the area is well ventilated, and while wearing an air-supplied respirator.

Arc rays from the welding process produce intense visible and invisible (ultraviolet and infrared) rays that can burn eyes and skin. Sparks fly off from the weld.

Wear an approved welding helmet fitted with a proper shade of filter lenses to protect your face and eyes when welding or watching.

Wear approved safety glasses with side shields under your helmet.

Use protective screens or barriers to protect others from flash, glare and sparks; warn others not to watch the arc.

Wear protective clothing made from durable, flame-resistant material (leather, heavy cotton, or wool) and foot protection.

Welding on closed containers, such as tanks, drums, or pipes, can cause them to blow up. Sparks can fly off from the welding arc, causing fires and burns. Accidental contact of electrode to metal objects can cause sparks, explosion, overheating, or fire.

Remove all flammables within 35 ft (10.7 m) of the welding arc. If this is not possible, tightly cover them with approved covers.

Do not weld where flying sparks can strike flammable material.

Protect yourself and others from flying sparks and hot metal.

Be alert that welding sparks and hot materials can easily go through small cracks and openings to adjacent areas.

Watch for fire, and keep a fire extinguisher nearby.

Be aware that welding on a ceiling, floor, bulkhead, or partition can cause fire on the hidden side.

Do not weld on closed containers unless they are properly prepared according to AWS F4.1.

Connect work cable to the work as close to the welding area as practical.

Do not use welder to thaw frozen pipes.

Remove stick electrode from holder or cut off welding wire at contact tip when not in use.

Wear oil-free protective garments such as leather gloves, heavy shirt, cuffless trousers, high shoes, and a cap.

Remove any combustibles, such as a butane lighter or matches, from your person before welding.

Follow requirements in OSHA 1910.252 (a) (2) (iv) and NFPA 51B for hot work and have a fire watcher and extinguisher nearby.

Do not install or place unit on, over, or near combustible surfaces.

Do not install unit near flammables.

Do not overload building wiring – be sure power supply system is properly sized, rated, and protected.

Welding, chipping, wire brushing, and grinding cause sparks and flying metal. As welds cool, they can throw off slag.

Wear approved safety glasses with side shields even under your welding helmet.

Shielding gas cylinders contain gas under high pressure. If damaged, a cylinder can explode.

Shut off shielding gas supply when not in use.

Always ventilate confined spaces or use approved air-supplied respirator.

Protect compressed gas cylinders from excessive heat, mechanical shocks, physical damage, slag, open flames, sparks, and arcs.

Install cylinders in an upright position by securing to a stationary support or cylinder rack to prevent falling or tipping.

Keep cylinders away from any welding or other electrical circuits.

Never drape a welding torch over a gas cylinder.

Never allow a welding electrode to touch any cylinder.

Never weld on a pressurized cylinder – explosion will result.

Use only correct shielding gas cylinders, regulators, hoses, and fittings designed for the specific application; maintain them in good condition.

Turn face away from valve outlet when opening cylinder valve.

Keep protective cap in place over valve except when cylinder is in use or connected for use.

Read and follow instructions on compressed gas cylinders, associated equipment, and Compressed Gas Association (CGA) publication P-1.

Do not touch hot parts bare handed.

Allow cooling period before working on gun or torch.

To handle hot parts, use proper tools and/or wear heavy, insulated welding gloves and clothing.

Magnetic fields from welding can affect pacemakers.

Pacemaker wearers keep away.

Wearers should consult their doctor before going near arc welding, gouging, or spot welding operations.

Noise from some processes or equipment can damage hearing.

Wear approved ear protection if noise level is high.

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 your body.

4. Keep welding power source and cables as far away from operator as practical.

5. Connect work clamp to workpiece as close to the weld as possible.

Regarding Pacemakers: Pacemaker wearers consult your doctor before welding or going near welding operations. If cleared by your doctor, then following the above procedures is recommended.

Consider the placement for safety and convenience:

Do not put the feeder where welding wire hits the gas cylinder.

Do not move or operate equipment when it could tip.

Choose a slot for the rubber feet that allows all feet to sit securely on top of the welding power source.

Ensure shielding gas pressure does not exceed 100 PSI (689 kPa).

1. Connect the 14-Pin Control Cable (10 ft / 3.0 m).

2. Connect the customer-supplied gas hose with 5/8-18 right-hand threads to the Shielding Gas Valve Fitting. Ensure gas pressure does not exceed 100 PSI (689 kPa).

3. Connect the Weld Cable to the Weld Cable Terminal.

Tools Needed: 9/16 in, 5/8 in, 3/16 in wrenches/sockets.

To rotate the drive assembly:

1. Loosen the Drive Assembly Rotation Knob.

2. Rotate the drive assembly to the desired position.

3. Tighten the Drive Assembly Rotation Knob securely.

1. Install the wire spool onto the hub. Adjust the tension nut so the wire is taut when the wire feed stops.

2. Install the correct wire guides and anti-wear guide for your wire size.

3. Install the correct drive rolls for your wire type and size.

4. Ensure the outlet cable has the proper size liner for the welding wire size. When installing the gun, position the liner (extending from the outlet wire guide) as close as possible to the drive rolls without touching.

5. Install the gun. Lay the gun cable out straight.

6. Cut off the bent end of the wire.

7. Push the wire through the guides up to the drive rolls; continue to hold the wire.

8. Press the Jog button (or gun trigger) to feed the wire out through the gun. Caution: Do not point the gun toward any part of the body, other people, or any metal when threading welding wire.

9. Adjust drive roll pressure: Hold the nozzle about 2 in (51 mm) from a nonconductive surface (like wood) and press the gun trigger to feed wire against the surface. Tighten the pressure adjustment knob(s) so the wire does not slip. Do not overtighten. If the contact tip is completely blocked, the wire should slip at the feeder. For soft wire or small diameter stainless steel wire, reduce the drive roll pressure on the rear roll to half that of the front rolls.

10. Cut the wire off close to the nozzle.

11. Close the drive roll cover.

Tools Needed: 3/16, 5/64 in hex keys; 15/16, 3/8 in wrenches.

1. Turn off the unit and remove the wrapper (1/4 in tool needed).

2. Locate DIP switch S1 on the Motor Control Board PC1.

3. Set the switches according to the desired function. The elevated slider (white in illustrations) indicates the switch position.

4. Reinstall the wrapper.

5. Turn the unit On. DIP switches are only read on power-up.

S1-1 and S1-2 Functions:

Automatic Run-In (Factory Default: ON)

ON: Run-In speed is approximately 1/2 weld wire feed speed.

OFF: Run-In speed is set using potentiometer P1 located on Motor Board PC1.

Current Detect Override (Factory Default: OFF)

ON: Current detect override. Use for welding power sources that don’t provide current feedback through the 14-pin receptacle (Pins F & H not present). Run-in is inactive.

OFF: Current must be detected from power sources that provide current feedback through the 14-pin receptacle to go from run-in to welding condition. Run-in is active.

1. Turn off the unit and remove the wrapper (1/4 in tool needed).

2. Locate the DIP switches on the meter board (refer to diagrams in the PDF for exact location).

3. Set the switches according to the desired display units and motor type (Standard or High Speed).

Digital Meter Function Settings:

Configure switches 1-5 based on the diagrams provided in the PDF (Section 5-8) for:

Standard Motor – Inches/Minute

Standard Motor – Meters/Minute

High Speed Motor – Inches/Minute

High Speed Motor – Meters/Minute

4. Reinstall the wrapper.

5. Turn the unit On.

The Jog/Purge Push Button allows the operator to jog wire without energizing the weld power or gas valve circuit.

The wire feeder can also be jogged by using the gun trigger. However, the contactor is energized for 3 seconds.

If the welding arc does not initiate in 3 seconds after the gun trigger is activated, the unit will perform a jog operation for a maximum of two minutes. If the gun trigger is still activated after two minutes, the jog operation is terminated.

Jog speed can be adjusted with the Wire Speed control when the unit is jogging wire. If equipped with meters, the unit displays jog speed while the unit is being jogged.

Pressing the Jog/Purge button also allows the operator to purge gas lines before welding and to preset gas pressure at the regulator.

Trigger hold allows the operator to weld without continuously holding the gun trigger.

1. Place the Trigger Hold switch in the On position.

2. Press and hold the gun trigger for a minimum of 2 seconds, but not longer than 6 seconds, then release it.

3. Welding will continue after the trigger is released.

4. To stop welding, press the trigger again.

Voltage Control (3): Use this control to adjust the voltage output of the welding power source.

Voltmeter (1): Displays the actual or preset voltage from the welding power source through the 14-pin control cable.

Wire Speed Meter (2): Factory set to display inches per minute (ipm). To display meters per minute (mpm), see Section 5-8 for DIP switch settings.

You can adjust the preset voltage display on the wire feeder to match your power source’s display by adjusting potentiometer P2 on motor control board PC1 (See Section 7-2 for location).

Disconnect power before maintaining.

Every 3 Months:

Replace unreadable labels.

Clean and tighten weld terminals.

Repair or replace cracked weld cable.

Replace cracked plastic parts.

Check 14-pin cord for damage.

Check gas hose and fittings for leaks or damage.

Check gun cable for damage.

Every 6 Months:

Blow out or vacuum inside the unit. During heavy service, clean monthly.

Clean drive rolls.

Error conditions are indicated by LED3 on the Motor Control Board PC1 or on the display meter (if equipped). To view LED3, turn Off unit, remove the wrapper, and turn unit On. LED3 is most easily observed from the left side.

The LED blinks in a 2.5 second cycle. The number of blinks indicates the error type. Higher priority errors (more blinks) override lower ones.

Disconnect power before troubleshooting.

Each kit contains an inlet guide, intermediate guide, and 045 233 antiwear guide W/604 612 setscrew 8-32 x .125, along with 4 drive rolls.