L Bar Sealer Troubleshooting

For retail, wholesale, and commercial packaging applications, L bar sealers are used all over the globe. With two sealing sides, the sealer is used with a centerfold shrink film to fully enclose products into shrink film before heat is applied to shrink the material.

Because the L bar sealer is used for every seal, with heavy production, parts can have issues. The sealing blade is heated for every seal, and components around the sealing area can build up residue and wear. Other issues can also arise over time.

Below are some common troubleshooting ideas for the stand-alone L bar sealers sold at U.S. Packaging & Wrapping LLC. If you did not purchase your machine from us, we recommend referencing your user manual for troubleshooting. These are only a few ideas to consider if you are experiencing issues with your L bar sealer.

NO HEAT TO THE SEALING BLADE

1. Check that the sealer is plugged in and that power is present at the socket. Make sure the power switch is in the ON position. Incoming power and the power turned on are essential for the sealer to work.
2. Make sure the timer is not set to zero (0) on the timer dial. The seal timer should have some time set on it to ensure the heat will engage when the bar is closed.
3. Check to be sure the microswitch is engaging when the sealer is closed.
   1. Make sure the switch is being activated when the seal bar is down.
   2. Press the switch by hand. If no click is heard, the switch may need to be replaced.
4. Check all fuses. One of the most common issues is no heat to the sealing blade.
5. Check to see if the contactor or relay engages with the main switch of the sealer is turned on.
6. Check for voltage present at both the primary and secondary of transformer T2, as per the values shown in the voltage specifications.
7. Check for a broken sealing blade inside or outside the corner block.

• UNBALANCED HEAT FROM FRONT AND SIDE SEALING AREAS

1. Check the brass corner block and ensure the Teflon insulation covering the sealing blade is securely in place. If the Teflon insulation is missing or worn out, the band ribbon will ground against the corner block, preventing heat from transferring into the corner.
2. Check for poor connection in the compensator blocks where the sealing element connects on each end.
3. Look for uneven residue buildup concentrated more on one side.

• WEAK SEALS AND/OR POOR FILM CUT-OFF

1. Improper setting of the sealing timer. If the seal time is not set correctly, the seals will not come out correctly.
2. Improper operating technique. There is too much film tension; ensure the film is relaxed before sealing.
3. Check the band ribbon to see if cleaning or replacement is necessary.
4. Burned Teflon tapes ½” or ¾” replace. If Teflon tapes become burned or worn, a weak seal may occur.
5. A wavy silicone rubber sealing pad would be located opposite the heating element. If grooves become worn in the pads, they will prevent proper seals.
6. Seal pad pressure is incorrect. This would require adjusting magnets for more pressure during the seal or the operator pressing down more when making a seal if a manual seal is needed.

• TAKE AWAY CONVEYOR WILL NOT RUN

1. Check conveyor time. Make sure it is not set to zero (0).
2. Check the fuses and wires to the conveyor.
3. Check the conveyor belt and make sure it is not adjusted too tightly. Adjust the conveyor belt using the Drive Roller Adjustment screw.
4. Check that the conveyor motor sprocket set screws are not loose on the shaft.
5. Check that the conveyor chain is not jammed or broken. Film and other debris can occasionally become entangled in it.
6. Be sure any relays running to the conveyor are correctly working.

• EXCESSIVE FILM DRAG WHEN PREPPING PRODUCT

1. Check for proper film threading. Improper threading can cause drag and keep the film from properly dispensing.
2. Loosen film roll brake. The dispenser should have a break to keep the shrink film roll from releasing too much film.
3. Ensure the film separator is positioned correctly on the film. Incorrect positioning can lead to drag and tearing.

• EXCESSIVE FILM UNWINDING OR “SPILL”

1. Tighten the film roll brake. No brake or too loose of a brake can cause excess film.
2. Check film threading. Improper threading can lead to excessive unwinding.
3. Be sure the roll fits entirely into the roll rack. Any rolls sitting on top of the dispenser will not properly dispense.

Proper maintenance and how the machine is used will impact the possible issues with an L bar sealer. Use these troubleshooting tips to help determine what could be causing your sealer issues, but always reference the machine user manual before making any adjustments. U.S. Packaging & Wrapping offers parts and troubleshooting on machines we sell. Visit our website at https://uspackagingandwrapping.com/ or contact us at 1-800-441-5090.