Section 5 − Maintenance &Troubleshooting; Routine Maintenance; Circuit Breaker Cb1; Overheating - Miller Millermatic 300 Owner's Manual

SECTION 5 − MAINTENANCE &TROUBLESHOOTING

5-1. Routine Maintenance

3 Months
Replace unreadable labels
Clean and tighten weld terminals
6 Months
Blow out or vacuum inside.

5-2. Circuit Breaker CB1

1

5-3. Overheating

Thermostats TP2 and TP3 protect the unit from damage due to overheating. If main transformer T1 or rectifier Z1 gets
too hot, TP2 and/or TP3 opens and output stops. The fan keeps running to cool the unit. Wait several minutes before
trying to weld.
OM-1321 Page 20
Repair or replace
cracked weld cable
OR
3
Y Disconnect power
before maintaining.
Check gun
cable.
Clean
drive rolls.
1 Circuit Breaker CB1
If CB1 opens, wire feeding stops.
2 Welding Gun (Not Included)
Check gun liner for blockage or
kinks.
3 Wire Drive Assembly
Check for jammed wire, binding
drive gear or misaligned drive rolls.
2
Allow cooling period and reset
breaker. Close door.
.
Maintain more often
during severe conditions.
Ref. 802 517-A