Fronius MTG 250i Instructions De Service page 49

The welding torch becomes very hot
Cause: Only on Multilock welding torches: torch neck union nut is loose
Remedy: Tighten the union nut
Cause: Welding torch operated above the maximum welding current
Remedy: Reduce welding power or use a more powerful welding torch
Cause: The specification of the welding torch is inadequate
Remedy: Observe the duty cycle and loading limits
Cause: Only on water-cooled systems: Inadequate coolant flow
Remedy: Check coolant level, coolant flow, coolant contamination, the routing of the
hosepack, etc.
Cause: The tip of the welding torch is too close to the arc
Remedy: Increase stick-out
Contact tip has a short service life
Cause: Incorrect wirefeeder rollers
Remedy: Use correct wirefeeder rollers
Cause: Wire electrode worn due to excessive contact pressure on the wirefeeder roll-
ers
Remedy: Reduce contact pressure on the wirefeeder rollers
Cause: Wire electrode contains impurities/is corroded
Remedy: Use high-quality wire electrode with no impurities
Cause: Uncoated wire electrode
Remedy: Use wire electrode with suitable coating
Cause: Wrong dimension of contact tip
Remedy: Use a contact tip of the correct dimension
Cause: Duty cycle of welding torch has been exceeded
Remedy: Shorten the duty cycle or use a more powerful welding torch
Cause: Contact tip has overheated. No thermal dissipation as the contact tip is too
loose
Remedy: Tighten the contact tip
NOTE!
Risk when using CrNi wire electrodes
This may result in a higher degree of contact tip wear.
► When using CrNi, the contact tip may be subject to a higher degree of wear due to the
nature of the surface of the CrNi wire electrode.
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