Troubleshooting - Miller Electric Millermatic 250 Owner's Manual

4-10. Troubleshooting

Trouble
No weld output; wire does not feed.
No weld output; wire feeds.
Low weld output.
Fan motor does not run.
NOTE: Fan only runs when cooling
is necessary.
Low, high, or erratic wire speed.
No wire feed.
Poor weld bead, or welding
wire is noodle welding.
OM-1308 Page 16
Be sure line disconnect switch is On (see Section 2-11).
Replace building line fuse or reset circuit breaker if open (see Section 2-11).
Reset circuit breaker CB1 (see Section 4-2).
Secure gun trigger connections (see Section 2-5).
Check and replace Power switch if necessary.
Have Factory Authorized Service Agent check all board connections and main control board.
Thermostat TP1 open (overheating). Allow fan to run; the thermostat will close when the unit has cooled
(see Section 2-2).
Connect work clamp to get good metal to metal contact.
Replace contact tip (see Section 4-4).
An overload condition occurred. Release gun trigger (see Section 4-3).
Have Factory Authorized Service Agent check main control board and main rectifier.
Connect unit to proper input voltage or check for low line voltage (see Section 2-11).
Check input voltage jumper links and correct position if necessary (see Section 2-9).
Have Factory Authorized Service Agent check main control board.
Have Factory Authorized Service Agent check fan-on-demand circuit.
Readjust front panel settings (see Section 3-1).
Place Low Range/Full Range switch in correct position (see Section 3-1).
Change to correct size drive rolls (see Section 4-5).
Readjust drive roll pressure (see Section 2-12).
Replace inlet guide, contact tip, and/or liner if necessary (see Sections 4-4, and 4-8).
Check position of input jumper links (see Section 2-9).
Have Factory Authorized Service Agent check main control board.
Reset circuit breaker CB1 (see Section 4-2).
Turn Wire Speed control to higher setting (see Section 3-1).
Clear obstruction in gun contact tip or liner (see Sections 4-4 and 4-8).
Readjust drive roll pressure (see Section 2-12).
Change to correct size drive rolls (see Section 4-5).
Rethread welding wire (see Section 2-12).
Check gun trigger and leads. Repair or replace gun if necessary.
Have Factory Authorized Service Agent check main control board.
Check polarity setting for type of welding wire being used (see Section 2-6).
Remedy