Miller Multimatic 255 User Manual

OWNER’S MANUAL
OM-278174E
2021-12
Processes
Multiprocess Welding
Description
Arc Welding Power Source And Wire
Feeder
For product information,
Owner’s Manual translations,
and more, visit
www.MillerWelds.com
Multimatic
®
255

Miller Multimatic 255 Specifications

General

Output Voltage Range	10 - 26.5 V
Input Phase	1-Phase
Output Amperage Range	5 - 230 A
Duty Cycle	60% at 230 A
Welding Processes	MIG, TIG, Stick, Flux-Cored
Weight	84 lbs (38 kg)
Wire Feed Speed Range	50 - 800 IPM
Input Voltage	208 V, 220 V, 230 V, 240 V, 380 V, 400 V, 415 V, 440 V, 460 V, 480 V, 500 V, 575 V

Summary

SECTION 1 - SAFETY PRECAUTIONS - READ BEFORE USING

1-2. Arc Welding Hazards

Details the primary hazards associated with arc welding processes.

Welding Can Cause Fire or Explosion

Risks of fire and explosion associated with welding operations.

Additional Hazards For Installation, Operation, And Maintenance

Covers hazards related to equipment installation, operation, and maintenance.

SECTION 4 – SPECIFICATIONS

4-9. Duty Cycle And Overheating For MIG

Duty cycle charts and information on preventing overheating for MIG welding.

4-10. Duty Cycle And Overheating For Stick

Duty cycle charts and information on preventing overheating for Stick welding.

4-11. Duty Cycle And Overheating For TIG

Duty cycle charts and information on preventing overheating for TIG welding.

SECTION 5 – INSTALLATION

5-2. Electrical Service Guide

Recommendations for electrical service requirements for safe operation.

5-3. Connecting 1-Phase Input Power

Instructions for connecting the unit to a 1-phase input power supply.

SECTION 6 – OPERATION

6-1. Controls

Overview of the unit's control panel, buttons, and knobs for operation.

6-3. Using Auto-Set Elite

Guide to using the Auto-Set Elite feature for optimized welding parameters.

6-4. Using Manual Mode

Instructions for operating the welding unit in Manual Mode.

6-5. Manual MIG Set-Up Mode

Configuring settings for Manual MIG welding processes.

6-6. Manual Stick Set-Up Mode

Configuring settings for Manual Stick welding processes.

6-7. Manual TIG Set-Up Mode

Configuring settings for Manual TIG welding processes.

6-11. Pulsed MIG Auto-Set Mode

Using Auto-Set mode specifically for pulsed MIG welding.

6-12. Pulsed MIG Manual Mode

Operating in Manual Mode for pulsed MIG welding.

6-13. Pulsed TIG Manual Mode

Operating in Manual Mode for pulsed TIG welding.

SECTION 10 – GMAW WELDING (MIG) GUIDELINES

10-17. Troubleshooting Guide For Semiautomatic Welding Equipment

Troubleshooting common issues with semiautomatic welding equipment.

10-8. Troubleshooting – Excessive Spatter

Diagnosing and fixing issues causing excessive spatter during MIG welding.

10-9. Troubleshooting – Porosity

Diagnosing and fixing porosity issues in welds.

10-10. Troubleshooting – Excessive Penetration

Diagnosing and fixing issues related to excessive weld penetration.

10-11. Troubleshooting – Lack Of Penetration

Diagnosing and fixing issues related to lack of weld penetration.

10-12. Troubleshooting – Incomplete Fusion

Diagnosing and fixing incomplete fusion issues in welds.

10-13. Troubleshooting – Burn-Through

Diagnosing and fixing weld burn-through issues.

10-14. Troubleshooting – Waviness Of Bead

Diagnosing and fixing wavy weld bead issues.

10-15. Troubleshooting – Distortion

Diagnosing and fixing weld distortion issues.

SECTION 11 – STICK WELDING (SMAW) GUIDELINES

11-1. Stick Welding Procedure

Step-by-step procedure for performing stick welding.

11-2. Electrode And Amperage Selection Chart

Chart for selecting electrodes and amperage for stick welding.

11-3. Striking An Arc

Techniques for initiating an arc during stick welding.

11-13. Troubleshooting

Troubleshooting common stick welding issues and their solutions.