MP251SiLCD Multi-Process Welder Owner’s Manual WARNING: Read carefully and understand all ASSEMBLY AND OPERATION INSTRUCTIONS before operating. Failure to follow the safety rules and other basic safety precautions may result in serious personal injury.
Thank you very much for choosing a Klutch® product! For future reference, please complete the owner’s record below: Serial Number/Lot Date Code (if applicable): _____________________ Purchase Date: ____________________________________________ Save the receipt, warranty, and this manual. It is important that you read the entire manual to become familiar with this product before you begin using it. This product is designed for certain applications only.
Table of Contents Intended Use .......................................................................................................................................... 4 Packaging Contents .............................................................................................................................. 4 Technical Specifications ...................................................................................................................... 5 Important Safety Information .................
Intended Use The Klutch MP251SiLCD Multi-Process Welder is an inverter-powered, wire feed welder for flux core and MIG welding plus a DC stick welder. It uses a state-of-the-art LCD control screen for easy set-up. It comes complete with a regulator and gas hose for easy connection for MIG welding plus a weld cable and electrode holder for DC stick welding. Directly connect this unit to a 230V NEMA 6-50R receptacle. It is designed to weld materials as thin as 24 gauge all the way up to 1/2" in a single pass.
Technical Specifications Property Specification Power Supply 230V, 45A, 50/60 Hz, Single Phase No-Load Voltage 69V DC Output Range – MIG/FLUX Core 40 to 250A DC Output Range - STICK 20 to 200A DC Output Range - TIG 15 to 250A DC Duty Cycle - MIG 20% @ 250A Duty Cycle – Stick 20% @ 200A Duty Cycle – TIG 20% @ 250A Suggested Wire Steel, Stainless Steel, Aluminum Suggested Wire Diameter .023, .030; .035, .
⚠WARNING PROP 65 • This product can expose you to chemicals including lead, which is known to the State of California to cause cancer. For more information, go to www.p65warnings.ca.gov. • Some dust created by power sanding, sawing, grinding, drilling, and other construction activities contains chemicals known to the state of California to cause cancer, birth defects, or other reproductive harm.
• Wear the proper personal protective equipment when necessary. Use an ANSI Z87.1 compliant welding helmet. Use a dust mask in dusty work conditions. Also use non-skid safety shoes, hardhat, gloves, dust collection systems, and hearing protection when appropriate. This applies to all persons in the work area. • Do not overreach. Keep proper footing and balance at all times. ⚠CAUTION PRODUCT USE AND CARE • Do not force the product.
Always replace or repair damaged components before using the welder. • Check all components to ensure they are clean and in good operating condition before use. ⚠CAUTION During Operation Do not operate the welder if the output cable, electrode, torch, or any accessories are wet. Do not immerse them in water. These components and the welder must be completely dry before attempting to use them. • Follow the instructions in this manual. • Keep the welder in the OFF position when not in use.
• Do not use a welder to thaw frozen pipes. ⚠WARNING Fumes and Gases • Do not use the welder in the presence of gasoline, diesel, propane, or other flammable liquids. Sparks created from the welder may ignite liquids or fumes, causing an explosion and serious injury or death. • Fumes emitted from the welding process displace clean air and can result in injury or death. • Do not breathe in fumes emitted by the welding process. Make sure your breathing air is clean and safe.
• Do not operate any electric arc welder in areas where flammable or explosive materials are present. • Remove all flammable materials within 35 feet of the welding arc. • Take precautions to ensure that flying sparks do not cause fires or explosions in hidden areas, cracks, or areas you cannot see. • Keep a fire extinguisher close in the case of fire. • Wear garments that are oil-free with no pockets or cuffs that will collect sparks.
• Be sure all equipment in the welding area is electromagnetically compatible. • To reduce possible interference, keep weld cables as short as possible, close together, and down low, such as on the floor. • Locate welding operation 100 yards from any sensitive electronic equipment. • Be sure this welding machine is grounded. • If interference still occurs, the user must take extra measures such as moving the welding machine, using shielded cables, using line filters, or shielding the work area.
Your tool must be plugged into an appropriate outlet, properly installed and grounded in accordance with all codes and ordinances. The plug and outlet should look like those in the following illustration. Double Insulated Tools: Tools with Two-Prong Plugs Tools marked Double Insulated do not require grounding. They have a special double insulation system which satisfies OSHA requirements and complies with the applicable standards of Underwriters Laboratories, Inc.
Minimum Wire Size Of Extension Cords Cord Length Nameplate AMPS 25' 50' 100' 150' 0-6 18 AWG 16 AWG 16 AWG 14 AWG 6-10 18 AWG 16 AWG 14 AWG 12 AWG 10-12 16 AWG 16 AWG 14 AWG 12 AWG 12-16 14 AWG 12 AWG NOT RECOMMENDED • When using more than one extension cord to make up the total length, make sure each cord contains at least the minimum wire size required.
Main Parts of MP251SiLCD Reference Subassembly 1 MP251SiLCD 2 MIG Torch 3 Ground Cable & Clamp 4 Regulator/Flow Gauge (2) 5 Gas Hose (2) 6 MIG Accessory Kit 7 TIG Torch with extra Collets, Long Cap, Short Cap, Sample Tungsten, and #5, #6, #7 Nozzles Page 14 of 58
Setting Up Equipment ⚠WARNING ELECTRIC SHOCK CAN KILL! • High voltage danger from power source! Consult a qualified electrician for proper installation of receptacle. This welder must be grounded while in use to protect the operator from electrical shock. • Do not remove the grounding prong or alter the plug in any way. Use only the supplied adapter between the welder's power cord and the power source receptacle.
c. Remove the drive roller by turning the drive roll securement knob (4) counterclockwise. Carefully slide the drive roll assembly off the drive shaft. This drive roll assembly consists of three pieces. The outer drive roll, inner drive roll, and a key. Be careful not to misplace the key. d. Based on the wire diameter, select the correct groove. When installing the drive roller, the number stamped on the drive roller for the wire size you are using should be facing you.
iii. Remove the packaging from the spool of wire and then identify the leading end of the wire secured on the edge of the spool. DO NOT UNHOOK IT AT THIS TIME. iv. Place the spool on the spool hub so the wire will pull off the bottom of the spool. The welding wire should always come off the bottom of the spool into the drive mechanism (Figure 4). Figure 4 v. The welder can use either 8 inch or 11-inch spools. The wire spool retainer secures the spool of wire onto the spool hub.
vii. With the welder disconnected from the power source, remove the leading end of the wire from the spool. Hold on to it securely, so as not to allow unspooling or tangling of the wire as it will result in tangled wire and feeding problems. viii. Cut off any bent portion of the wire using a wire cutter. ix. Loosen the tension adjusting knob holding the drive tension arm in place and lift the tension arm up off the drive roller. x.
5. SETTING THE DRIVE ROLL TENSION ⚠WARNING • Arc flash can injure eyes! To reduce the risk of arc flash, make certain that the wire coming out of the end of the torch does not come in contact with the work piece, ground clamp, or any grounded material during the drive tension setting process or arcing will occur. a. Press the trigger on the torch. b. Turn the drive tension adjustment knob (Figure 2) clockwise until the wire seems to feed smoothly without slipping. 6.
2 3 4 1 5 7 6 Reference Subassembly 1 Gas Bottle Valve 2 Gas Flow Gauge (Set at 20 CFH) 3 Gas Pressure Gauge 4 Regulator 5 Gas Flow Adjuster 6 Gas Hose Connection 7 Gas Cylinder Figure 6 iv. Connect the other end of the gas hose to the gas hose connection on the supplied regulator/flow gauge. Use a wrench to snug up the connection. v. Before installing the regulator, it is good practice to make certain no debris is in the gas bottle connection.
is located on the back panel of the welder and activated by the trigger. Gas flow should be heard when the trigger is activated. No gas flow will result in a harsh arc with excessive spatter; a smooth weld bead will be difficult to obtain. Avoid unnecessary gas loss by closing the tank valve when finished welding. viii. Gas Selection Different materials require different shielding gases when MIG welding (refer to the set-up LCD window).
Figure 8 3. Insert the back end of the MIG torch into the MIG socket on the front of your machine (Figure 8). Make certain to completely slide the torch all the way in. Slightly twist to assist with pushing the torch to the back of the receptacle. The retaining bolt can then be tightened, making certain the bolt sets down into the retaining groove on the back of the MIG torch. 4.
3. Carefully slide the gas connector and the weld power connection through the weld cable access opening in the front of the machine (Figure 10). Figure 10 4. Open the wire compartment door. 5. Connect the gas connection quick connector to the gas connector (1) on the back panel of the wire compartment. 6. Connect the weld power connection to the bolt on the top of the MIG connector (2). 7. Connect the 5-Pin trigger connector to the 5-Pin receptacle for the spool gun, on the front of the machine (3). 8.
1. Remove the ground cable and the electrode holder from the weld output connections. Install the ground cable to the Positive (+) weld output connection (Figure 8). 2. Secure the ground clamp to the work piece. 3. Connect a regulator to a bottle of ARGON gas. Then connect the gas connection from the TIG torch to the regulator. 4. Connect the TIG torch weld cable to the Negative (-) weld output connection. 5. Set the desired amperage on the amperage control knob on the front panel of the welder. 6.
UNDERSTANDING THE FRONT PANEL Reference Description 1 LCD Display 2 Gas Purge Button 3 Wire Jog Button 4 Voltage Control Knob 5 Multi-Function Adjustment/Selection Knob 6 Previous Screen Button 7 Start Button Page 25 of 58
GENERAL SYSTEM SET-UP 1. Press the ENTER BUTTON. 2. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to the SETTING selection. 3. Push in the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB. 4. Language a. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to the LANGUAGE screen. b. Press the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to change the orange outline to solid orange background. c. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to TO YOUR PREFERRED LANGUAGE. d.
6. Brightness a. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB until BRIGHTNESS screen is displayed. b. Push in the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB so the brightness setting has an orange background. c. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to selected desired screen brightness. d. Push in the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to select. 7. To read software version a. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB until INFORMATION screen is displayed. 8.
b. Press the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to change the orange outline to solid orange background. c. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to choose YES or NO for a factory reset. d. Push in the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to select. e. Press the ENTER button to return to the main screen. WIRE WELDING SET-UP 1. Press the ENTER BUTTON. 2. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to the SETTING selection you need.
c. MIG Stainless Steel d. MIG Al (Aluminum) i. Choose if you will be using a spool gun. ii. Choose which wire alloy you will be using. NOTE: WELDING ALUMINUM WITH THE MIG GUN CAN BE DIFFICULT. We always suggest the use of a spool gun to avoid feeding problems associated with a soft aluminum wire. e.
f. Manual MIG 3. Follow the on-screen display that shows the weld cable connections a. For MIG Steel with shielding gas – Connect the WELD POWER CABLE to the Positive (+) weld output connection. Then the ground cable to the Negative (-) weld output connection. b. For MIG Steel without shielding gas – Connect the WELD POWER CABLE to the Negative (-) weld output connection. Then the ground cable to the Positive (+) weld output connection. c.
5. Choose Wire Size a. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to the wire size you need. Press in the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to make your selection. 6. Choose the thickness of material a. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to change the thickness of material. Press in the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to make your selection. 7. Your Welder is now ready to weld! 8.
a. From the screen above, push in the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB so the orange highlight turns into an orange outline. Then turn the MULTIFUNCTION ADJUSTMENT/SELECTION KNOB clockwise until the inductance icon is outlined. Press the MULTI-FUNCTION ADJUSTMENT/SELECTION to highlight in orange. b. Adjust inductance Up to increase the arc cycle time, and there by increasing the fluidity or wetting of the puddle. This will result in a wider and more even transition at the toes of the weld. c.
b. Press the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to select. c. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to adjust the Pre-Gas Time. d. Press the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to confirm. 14. Run In WFS – Run In WFS allows you to adjust the speed of the wire feeding; after you pull the trigger and just prior to a weld establishing. Wire that “Runs In” slower will generally provide a smoother and less “Poppy” arc starting. We recommend using the programmed Run In WFS setting.
c. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to adjust the Post Gas time. STICK WELDING SET-UP 1. Press the ENTER BUTTON. 2. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB until the Stick/MMA screen is displayed. 3. Push in the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to confirm your selection. 4. Follow the display set-up: a. Connect the Electrode Holder to the Positive (+) Weld Output Connection. b. Connect the Ground Cable to the Negative (-) Weld Output Connection. 5.
a. When the Amperage is highlighted in Orange, you are able to turn the MULTIFUNCTION ADJUSTMENT/SELECTION KNOB to increase or decrease amperage. 6. Push in the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to change the orange background to an orange outline. 7. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to Hot Start. 8. Push in the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to confirm your selection. 9. Adjusting Hot Start a.
a. Arc Force setting can be used while welding to help keep the electrode from “sticking”. It will provide a very short boost of output amperage when the arc is too short. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to the desired Arc Force Setting. b. Press the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to confirm your selection 13. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to VRD. 14. Push in the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to confirm your selection. 15. Adjusting VRD a.
a. Connect the TIG torch to the Negative (-) Weld Output Connection. b. Connect the Ground Cable to the Positive (+) Weld Output Connection 5. Adjusting Amperage a. Turn the MULTI-FUNCTION ADJUSTMENT/SELECTION KNOB to increase or decrease amperage. MIG OPERATION 1. POWER SWITCH - The power switch supplies electrical current to the welder. Whenever the power switch is in the ON position, the welding circuit is activated.
not exceed 1/4 inch or the arc may begin sputtering, signaling a loss in welding performance. d. TUNING IN THE WIRE SPEED - This is one of the most important parts of wire welder operation and must be done before starting each welding job or whenever the voltage setting, or wire diameter is changed. ⚠WARNING EXPOSURE TO A WELDING ARC IS EXTREMELY HARMFUL TO THE EYES AND SKIN! • Prolonged exposure to the welding arc can cause blindness and burns.
a. Moving the Torch - Torch travel refers to the movement of the torch along the weld joint and is broken into two elements: direction and speed. A solid weld bead requires that the welding torch be moved steadily and at the right speed along the weld joint. Moving the torch too fast, too slow, or erratically will prevent proper fusion or create a lumpy, uneven bead. Travel direction is the direction the torch is moved along the weld joint in relation to the weld puddle.
c. Welding Positions The FLAT POSITION is the easiest of the welding positions and is most commonly used. It is best if you can weld in the flat position, if at all possible, as good results are easier to achieve in this position.
The OVERHEAD POSITION is the most difficult welding position. Angle A (see HOLDING THE TORCH) should be maintained at 60 degrees. Maintaining this angle will reduce the chances of molten metal falling into the nozzle. Angle B should be held at zero degrees so that the wire is aiming directly into the weld joint. If you experience excessive dripping of the weld puddle, select a lower heat setting. Also, the weave bead tends to work better than the stringer. d.
NOTE: WHEN USING SELF-SHIELDING FLUX-CORE WIRE it is very important to thoroughly chip and brush the slag off each completed weld bead before making another pass or the next pass will be of poor quality. Fillet Weld Joints Most fillet weld joints, on metals of moderate to heavy thickness, will require multiple pass welds to produce strong joint. The following figure will show the sequence of laying multiple pass beads into a T fillet joint and a lap fillet joint. e.
burn-through method, larger wire diameters tend to work better than smaller diameters. Wire diameters that tend to work best, with the burn-through method are 0.035-inch self-shielding flux-core wire. Do not use 0.030-inch selfshielding flux core wires when using the burn-through method unless the metal is VERY thin or excessive filler metal build-up and minimal penetration is acceptable. Always select the HIGH heat setting with the burn-through method and tune in the wire speed prior to making a spot weld.
1. SETTING UP THE WORK PIECE a. Welding positions - There are two basic positions, for welding: Flat and Horizontal. Flat welding is generally easier, faster, and allows for better penetration. If possible, the work piece should be positioned so that the bead will run on a flat surface. b. Preparing the Joint- Before welding, the surface of work piece needs to be free of dirt, rust, scale, oil, or paint, or it will create brittle and porous welds.
3. ELECTRODE The welding electrode is a rod coated with a layer of flux. When welding, electrical current flows between the electrode (rod) and the grounded metal work piece. The intense heat of the arc between the rod and the grounded metal melts the electrode and the flux. 4. SELECTING THE PROPER ELECTRODE There is no golden rule that determines the exact rod or heat setting required for every situation.
6. WELDING TECHNIQUES The best way to teach yourself how to weld is with short periods of practice at regular intervals. All practice welds should be done on scrap metal that can be discarded. Do not attempt to make any repairs on valuable equipment until you have satisfied yourself that your practice welds are of good appearance and free of slag or gas inclusions. a. Holding the electrode The best way to grip the electrode holder is the way that feels most comfortable to you.
c. Types of weld bead The following paragraphs discuss the most used arc welding beads. The STRINGER BEAD is formed by traveling with the electrode in a straight line while keeping the electrode centered over the weld joint. Stringer Bead Weave Bead The WEAVE BEAD is used when you want to deposit metal over a wider space than would be possible with a stringer bead. It is made by weaving from side to side while moving with the electrode.
A. Weld speed is too fast. B. Weld speed is too slow. C. Arc is too long. D. Ideal weld. A solid weld bead requires that the electrode be moved slowly and steadily along the weld seam. Moving the electrode rapidly or erratically will prevent proper fusion or create a lumpy, uneven bead. ⚠WARNING ELECTRIC SHOCK CAN KILL! To prevent ELECTRIC SHOCK, do not perform any welding while standing, kneeling, or lying directly on the grounded workpiece. f.
DC TIG OPERATION ⚠WARNING High voltage danger from power source! • Consult a qualified electrician for proper installation of receptacle at the power source. This welder must be grounded while in use to protect the operator from electrical shock. If you are not sure if your outlet is properly grounded, have it checked by a qualified electrician.
9.3 Twist the torch to make contact between the work piece and the tungsten. 9.4 Lift torch away from the work piece about 1/8 inch. 9.5 Move down the joint to be welded by pushing the torch. 9.6 Insert filler metal in the leading edge of the weld puddle as needed. 10. To operate using Foot Pedal follow steps in DC TIG OPERATION on pages 49-50 in this manual. 10. Follow these steps for striking an arc using the Foot Pedal while TIG welding. 10.
Maintenance ⚠CAUTION Proper Care, Maintenance, and Repair • Always have the power disconnected when working on internal components. • Do not touch or handle the PC board without being properly grounded with a wrist strap. Put the PC board in a static proof bag to move or ship. • Do not put hands or fingers near moving parts such as the drive rolls of the fan. ⚠WARNING ELECTRIC SHOCK CAN KILL! • Touching live electrical parts can cause fatal shocks or severe burns. Do not touch live electrical parts.
⚠CAUTION Be aware that the Electrode will be electrically HOT when the Input Power Switch on the welder is turned on. Failure Unit Does Not Power Up. Protection Indicator Is On. Wire Drive Motor Does Not Turn. Wire Feeds Inconsistently. Cannot Create an Arc. Welding Arc is Unstable, Possible Cause Corrective Action Unit is not plugged in. Plug in unit. Input power circuit breaker is not on. Reset input power circuit breaker. The main power switch is not working. Replace main power switch.
Failure Creating Excessive Spatter. Possible Cause Corrective Action Ground clamp is not electrically connected to the work piece. Make certain the ground clamp Is connected to the work piece. Trigger Is not pressed. When in the MIG mode, this unit is not electrically hot until you press the torch trigger. Stick or TIG welding and machine is set for MIG welding. Make certain the SPOOL GUN/MIG TORCH/STICK WELDING selector switch is in the STICK position. The contact tip is too large.
Parts Diagram Parts List Reference Part Number Part Description Quantity 1 105200327 TORCH SELECTION SWITCH 1 2 105200328 MALE GAS QUICK CONNECT 2 3 105200052 FEMALE GAS QUICK CONNECT 2 4 105200292 CONTROL PCB 1 5 105200293 MAIN PCB 1 6 105200294 MAIN PCB SUPPORT BRACKET 1 7 105200295 REACTOR 1 8 105200296 HANDLE 1 9 105200297 PLASTIC FRONT BEZEL 1 10 105200298 LCD CONTROL PCB 1 Page 54 of 58
Reference Part Number Part Description Quantity 11 105200299 LCD SUPPORT PANEL 1 12 105200300 POTENTIOMETER KNOB 2 13 105200136 QUICK CONNNECTOR 2 14 105200060 GROUND CABLE & CLAMP 1 15 105200148 MIG TORCH 1 16 105200301 POLARITY SELECTOR WELD CABLE 1 17 105200302 BOTTOM 1 18 105200277 5-PIN TRIGGER RECEPTACLE 1 19 105200303 MIDDLE SUPPORT PANEL 1 20 105200055 MIG BLOCK 1 21 105200329 WIRE FEED DRIVE ASSEMBLY 1 ** 105200162 DRIVE ROLL .023/.
Reference Part Number Part Description Quantity 36 125300089 ENCLOSURE 1 ** 125400006 WELDER HELP LABEL 1 ** 105200041 MIG WARNING LABEL 1 37 105200296 HANDLE 1 OWNER’S MANUAL MP250Si LCD 1 ** ** 105200081 GAS HOSE TO REGULATOR 1 ** 105200082 INERT GAS REGULATOR 1 ** 105200087 ELECTRODE HOLDER WITH CABLE 1 Replacement Parts • For replacement parts and technical questions, please call Customer Service at 1-877-304-0294.
Limited Warranty Northern Tool and Equipment Company, Inc. ("We'' or "Us'') warrants to the original purchaser only ("You'' or "Your") that the Klutch® product purchased will be free from material defects in both materials and workmanship, normal wear and tear excepted, for a period of three years from date of purchase. The foregoing warranty is valid only if the installation and use of the product is strictly in accordance with product instructions.
Distributed by: Northern Tool & Equipment Company, Inc. Burnsville, Minnesota 55306 www.northerntool.
