01Photograph the failed heater
After safe shutdown and cooling, have maintenance remove the band. Note whether damage is near the clamp, the terminals, the sensor or across the whole band.
Record the setpoint, production rate and recent maintenance. The damage photo is easier to interpret with that history.
02Check the contact surface
Compare the barrel diameter with the band and check the clamp position. Residue, burrs and distortion can leave an air gap, making it harder for heat to reach the barrel.
Follow the manufacturer’s clamping and recheck instructions. Do not force a poorly fitting band closed or improvise shims.
03Check sensing and heater output
Verify sensor seating and zone identification. Have maintenance compare commanded output with the actual response. A sensor reading low may keep the heater on while a poorly seated section overheats.
Electrical tests belong with qualified personnel using the machine’s service procedure. Keep protective interlocks in service during diagnosis.
04Recheck under comparable conditions
After replacement, record temperature and output at a similar setpoint and production rate. If damage returns at the same location, revisit mounting and controls.
Send the old nameplate, contact-surface photos and failure location to the supplier for a review of watt density, leads and mounting.