MAINTENANCED-1
SAFETY PRECAUTIONS
WARNING
ELECTRIC SHOCK can kill.
•Have qualified person- nel do the maintenance and trouble shooting work.
•Turn the input power off at the fuse box before working on equipment.
•Do not touch electrically hot parts..
GUN TUBES AND NOZZLES
1.Replace worn contact tips as required.
2.Remove spatter from inside of gas noz- zle and from tip after each 10 minutes of arc time or as required.
CABLE CLEANING
Clean cable liner after using approximately 300 pounds (136 kg) of electrode. Remove the cable from the wire feeder and lay it out straight on the floor. Remove the contact tip from the gun. Using an air hose and only partial pressure, gently blow out the cable liner from the gas diffuser end.
ROUTINE MAINTENANCE
GENERAL MAINTENANCE
In extremely dusty locations, dirt may clog the air passages causing the welder to run hot. Blow dirt out of the welder with low- pressure air at regular intervals to eliminate excessive dirt and dust
The fan motors have sealed ball bearings which require no service.
DRIVE ROLLS AND GUIDE TUBES
After every coil of wire, inspect the wire drive mechanism. clean it as necessary by blowing with low pressure compressed air. Do not use solvents for cleaning the idle roll because it may wash the lubricant out of the bearing. All drive rolls are stamped with the wire sizes they will feed. If a wire size other than that stamped on the roll is used, the drive roll must be changed.
For instructions on replacing or changing drive roll, see “Wire Drive Roll” in Operation section or instruction decal inside the SP- 255 door.
CAUTION
Excessive pressure at the start may cause dirt to form a plug.
Flex the cable over its entire length and gain blow out the cable. Repeat this proce- dure until no further dirt comes out.
CONTACT TIP AND GAS NOZZLE INSTALLATION
1.Choose the correct size contact tip for the electrode being used (wire size is stencilled on the side of the contact tip) and screw it snugly into the gas diffuser.
2.Screw the appropriate fixed gas nozzle fully onto the diffuser. Either the standard
.50" (12.7 mm) flush nozzle or other optional flush or recessed (spray arc) nozzle sizes may be used. (See Accessories section.)
3.Be sure the nozzle insulator is fully screwed onto the gun tube and does not block the gas holes in the diffuser.
4.If using an optional adjustable slip on nozzle, slip the appropriate gas nozzle onto the nozzle insulator. Either a stan- dard .40" (12.7 mm) or optional .62" (15.9 mm) I.D.
