There are many different manufacturers of heat shrink tunnels, and a variety of issues can arise during the machine’s lifetime.

If you are having trouble with your shrink tunnel, we suggest referencing the machine’s user manual for troubleshooting, but the following list is a handful of basic components to check if your tunnel is down.

Use caution when working on your heat tunnels to avoid the danger of electrical shock. When power is not required for checking for the presence or value of voltages used, always have it disconnected.

Following are some common problems experienced with heat tunnel machines and some tips on how to address them. The use of a multimeter will be necessary to check continuity through different areas of the machine.

CONVEYOR MALFUNCTION

• Check for power at main power switch. It is important to have the correct voltage and amperage for your tunnel.
• Check conveyor motor fuse and replace if bad.
• Check motor capacitor. Be sure wires are not burned
• Check incoming power on Control Board
• Remove end covers and look for obstructed product or lodged rollers.
• Check lubrication of conveyor chains.
• Make sure the connection wire on the motor and cable is not loose.
• Check to make sure the chain is not loose and the sprockets are not touching the frame.
• Consider replacing the motor if all the above checks properly.

NO AIR FLOW

• Open main electrical panel. Check power at fuse for the blower motor.
• Remove end tunnel curtain and check to make sure no air holes are obstructed due to plastic build up covering air holes.
• Check main blower motor and replace if necessary.
• Check motor start capacitor to see if burned.
• Check motor wires for loose connection.
• Check for power across wires 7 and 15 (motor wires). If voltage is present and the motor still does not operate, replace motor.
• Remove safety screen covering blower wheel and check to make sure blower wheel is not loose on the blower motor shaft.

NO HEAT

• Check thermocouple wires at temperature controller (Terminals + and -) First, disconnect, then check with meter for continuity across the two thermocouple wires.
• If no continuity is present across thermocouple wires, replace thermocouple.
• Check for the proper voltage present with heater switch in ON position. If no power is present, check Fuses. If voltage present at wires and the Fuse is good, consider replacing the temperature control.
• Before replacing the temperature control, check for continuity with the lead wires disconnected from sensor.

NOTE: When any of the sensors are not functioning properly, this causes the temperature controller to malfunction.

• Check for the proper voltage on the contactors contactor pulled in under set temperature. If voltage is present on the contactor, check the Head Bank for broken lugs or wire inside the heater bank. If leads and jumper wires on Heater Bank are not broken or burned, then replace the Heater Bank.
• If no control over heat, interchange thermocouple wires at temperature controller. If still no control, check for replacement of a contactor or temperature control.

Be sure to reference your user manual for specific troubleshooting related to the brand of machine you have. U.S. Packaging & Wrapping offers parts and troubleshooting assistance for shrink tunnels we sell. Visit our website at https://uspackagingandwrapping.com/ or contact us at 1-800-441-5090.