Clarke HOTSHOT 185SG WE6442 Manuel De L'opérateur page 25

Failure to keep the nozzle adequately
cleaned can result in the following
problems:
A SHORTED nozzle results when spatter
buildup bridges the insulation in the nozzle,
allowing welding current to flow through it as
well as the contact tip. When shorted, a
nozzle will steal welding current from the
wire whenever it contacts the grounded work
piece. This causes erratic welds and reduced
penetration. In addition, a shorted nozzle
overheats the end of the gun, which can
DAMAGE the front-end of the gun.
A RESTRICTED nozzle is created when
enough slag builds up in the nozzle to affect
the direction, concentration, and/or rate of
the shielding gas flow. This problem can
cause porous, brittle welds and reduce
penetration.
TESTING FOR A SHORTED NOZZLE
Arcing between the nozzle and the work
piece ALWAYS means the nozzle is shorted,
but this can be hard to detect through the
lens of a welding helmet. The following
testing method is another way to tell if a
nozzle is shorted.
With the welder unplugged from the ac
power source, touch the probes of an
ohmmeter or continuity tester to the end of
the contact tip and the outside of the nozzle.
If there is any continuity at all, the nozzle IS
shorted. Clean or replace as needed.
PREVENTIVE MAINTENANCE
Except for internal and external cleaning,
cleaning the nozzle, and occasionally
retightening screws, there is no periodic
maintenance recommended for your welder.
TROUBLESHOOTING
The following TROUBLESHOOTING
table is provided as a guide to help resolve
some of the more common problems that
could be encountered. This table does not
provide all possible solutions, only those
possibilities considered to likely be common
faults. The table consists of a TROUBLE or
symptom, a POSSIBLE CAUSE for the
symptom, and a POSSIBLE REMEDY for
that symptom.
25