Short Circuit Shutdown; Troubleshooting - Miller DELTAWELD 302 Owner's Manual

4-2. Fuse F1
Tools Needed:
3/8 in

4-3. Short Circuit Shutdown

When contact tip is shorted and sticks to workpiece, the unit output falls to a safe operating level. To resume operation,
release gun trigger, turn Off unit, and remove contact tip from workpiece. Check contact tip and replace if damaged.
Turn On unit to continue operation.

4-4. Troubleshooting

Trouble
No weld output; unit completely inop-
erative.
No weld output; Power switch pilot light
on; fan on.
Unit provides only maximum or mini-
mum weld output.
Erratic or improper weld output.
No 115 volts ac output at duplex recep-
tacle, Remote 14 receptacle, or termi-
nal strip 1T.
No 24 volts ac output at Remote 14 re-
ceptacle, or terminal strip 1T.
Fan not operating. Note: fan runs only
when cooling is necessary.
OM-223 Page 20
Place line disconnect switch in On position (see Section 2-9).
Check fuse F1, and replace if necessary (see Section 4-2).
Check and replace line fuse(s), if necessary, or reset circuit breaker (see Section 2-9).
Check for proper input power connections (see Section 2-9).
Check for proper jumper link position (see Section 2-9).
If using wire feeder, place Output (Contactor) switch in Remote 14 position, and connect wire feeder
(see Sections 2-7 and 2-8). If feeder is not being used, place switch in On position (see Section 3-1).
Check, repair, or replace feeder (see wire feeder Owner's Manual).
Unit overheated. Allow unit to cool with fan On (see Section 3-2).
Have Factory Authorized Service Agent check control board PC1.
Have Factory Authorized Service Agent check control board PC1.
Use proper size and type of weld cable (see Section 2-5).
Clean and tighten all weld connections.
Check wire feeder installation according to Owner's Manual.
Have Factory Authorized Service Agent check control board PC1 and/or SCR in main rectifier.
Reset circuit breaker CB1 (see Section 2-4).
Reset circuit breaker CB2 (see Section 2-4).
Check for and remove anything blocking fan movement.
Have Factory Authorized Service Agent check fan motor.
Y Turn Off power before open-
1
1
Fuse F1 protects control transform-
er from overload. If F1 opens, weld
output and fan motor stops. Re-
place F1.
Remedy
ing rear access door.
Fuse F1 (See parts List For
Rating)
Ref. ST-800 101-C