Fault Phenomenon: Co-Nele KNL5500 lubrication is normal when cold. After continuous pumping for 4 hours (operating temperature), the lubrication pump stops working, no grease reaches the distributors, and a dashboard alarm sounds.

Troubleshooting Process:
– Checked lubricating grease: grade correct, no hardening.
– Checked lubrication pump motor: motor runs normally, not burnt.
– Checked lubrication lines: lines unobstructed, no leaks.
– Measured lubrication pump pressure switch at operating temperature: found pressure switch contacts stick due to heat.

Root Cause: High temperature causes the lubrication pump pressure switch contacts to stick, leading to a control logic error.

Required Parts: Lubrication pump pressure switch.