BossWeld MST195, Manual

39

  Issue

 
Power indicator is not lit, 
fan does not work and no 
output current

Power indicator is lit, fan 
works, no output current

 
 
Over temperature indicator 
is on, no output current

Output current is not stable.

Hot Welding Clamp

Excessive Spatter

Porosity - small cavities or 
holes resulting from gas 
pockets in weld metal

  Possible Reason

 
• Welder is not plugged into 
power supply
• Circuit breaker may have  
operated
• Main power switch may not be 
in the ON position 

• Output connectors may be 
disconnected or damaged
• Welding cables or earth clamp 
not connected properly 

• Duty cycle of the unit has 
been exceeded. .

• Earth clamp connection loose

• Mains Voltage is not constant
• Loose welding cables

• Leads reversed

Welding clamp rated current is 
too small,

• Wire feed speed set too high
• Voltage too high
• Wrong polarity set

• Stick out too long
• Contaminated base metal

Contaminated MIG wire

• Inadequate gas flow or too 
much gas flow

• Worn contact tip

• Wrong gas
• Inadequate gas flow or too 
much gas flow

• Moisture on the base metal

• Contaminated base metal

• Contaminated MIG wire

• Loose gas connection

  Suggested Remedy

 
• Check that the welder is plugged into the 
240V mains outlet and is switched on.
• Check that the mains fuse or breaker has not 
operated.
• Check that the main switch on the rear of the 
unit is in the on position. 

• Check output connectors are connected  
properly and are not damaged
• Check connections and that workpiece is free 
of paint and rust at connection point 

• Allow the unit to cool for 20 minutes

• Check earth clamp is connected to work piece 
properly.
• Change the Main Supply to an alternative
• Check the welding connectors are tight in the 
sockets. 
• Check Leads are not reversed and c/_

Replace with larger size welding clamp.

• Select lower wire feed speed
• Select a lower voltage setting
• Select the correct polarity for the wire being 
used 
• Bring the torch closer to the work
• Remove materials like paint, grease, oil, and 
dirt, including mill scale from base metal
• Use clean dry rust free wire. Do not lubricate 
the wire with oil, grease etc
• Check the gas is connected, check hoses, gas 
valve and torch are not restricted. Set the gas 
flow between 6-12 l/min flow rate. Check hoses 
and fittings for holes, leaks. Protect the welding 
zone from wind and drafts
• Change contact tip.

• Check that the correct gas is being used
• Check the gas is connected; check hoses, 
gas valve and torch are not restricted. Set the 
gas flow between 10 - 15 l/min flow rate. Check 
hoses and fittings for holes, leaks etc. Protect 
the welding zone from wind and drafts
• Remove all moisture from base metal before 
welding
•Remove materials like paint, grease, oil, and 
dirt, including mill scale from base metal
• Use clean dry rust free wire. Do not lubricate 
the wire with oil, grease etc.
Check and tighten connection.

TROUBLE SHOOTING