Fronius MTG 250i Instructions De Service page 47

Poor wirefeed
Cause: Depending on the system, brake force in wire-feed unit or power source set
too high
Remedy: Reduce the braking force
Cause: Hole in the contact tip is displaced
Remedy: Replace the contact tip
Cause: The inner liner or wire-guide insert is defective
Remedy: Check the inner liner and wire-guide insert for kinks, dirt, etc.
Change the faulty inner liner or wire-guide insert
Cause: The wirefeeder rollers are not suitable for the wire electrode being used
Remedy: Use suitable wirefeeder rollers
Cause: Wirefeeder rollers have the wrong contact pressure
Remedy: Optimise the contact pressure
Cause: The wirefeeder rollers are soiled or damaged
Remedy: Clean the wirefeeder rollers or replace them by new ones
Cause: Inner liner wrongly laid or kinked
Remedy: Replace inner liner
Cause: The inner liner has been cut too short
Remedy: Replace the inner liner and cut the new inner liner to the correct length
Cause: Wire electrode worn due to excessive contact pressure on the wirefeeder
rollers
Remedy: Reduce contact pressure on the wirefeeder rollers
Cause: Wire electrode contains impurities or is corroded
Remedy: Use high-quality wire electrode with no impurities
Cause: For steel inner liners: use of uncoated inner liner
Remedy: Use a coated inner liner
The gas nozzle becomes very hot
Cause: No thermal dissipation as the gas nozzle is too loose
Remedy: Screw on the gas nozzle as far as it will go
47