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Heat  Sealing  Equipment  for  Mil-Spec &  Industrial  Bag  Packaging  Applications

Troubleshooting Tips and Part # Information

Doboy HA-720 Hot Air Sealer

Following are recommended tips for troubleshooting Doboy HA-720 Hot Air Bag Sealer problems.  You will also find a list of part numbers and descriptions for commonly used parts.

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Preventative Maintenance & Proper Use Tips*

Area of Machine

Advice / Technique

One Heat Element Does Not Get Hot

(Applies to HA-720)

Heating Element wires may be loose or element is burned out. 

Check connections at temperature controller.  If both are tight, disconnect and check for continuity across heat element  wires.  

Solution: If no continuity, replace Heater Element.

Neither Heat Element Gets Hot

(Applies to HA-720)

Temperature controller may be broken.

Solution: Refer to Temperature controller manual and replace if necessary.

General Machine Set-up:

(Applies to Doboy HA-720)

We will gladly try to talk you through proper set-up of your machine - Call us!

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Troubleshooting Tips & Tricks*

Problem Possible Cause & Solution

PROBLEM: Contact us

(Applies to Doboy HA-720)

Contact us with your problems. We will post the solution here! Watch here for more Solutions, Tips, and Tricks!

* Machine troubleshooting & repairs should only be attempted by a qualified mechanic or electrician.  Power should always be disconnected prior to troubleshooting.

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Please see your factory instruction manual for additional troubleshooting tips.
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Common Replacement & Wear Parts (available at

Parts for Doboy HA-720 Series Machines
Spare Part # Description
* 292723 Heating Element with Cable
* 273656 Thermocouple
  421732 Temperature Controller - Call with Serial Number
  252463 #40 Carrier Chain - Call with Serial Number
  507168 Carrier Chain Connector Link
  200622 Chain Pressure Bar - Fixed Side (Rear Side)
  247465 Chain Pressure Bar Set - Spring Side (Front Side)
  246641 Spring - Compression [Use two (2) with each Pressure Bar Set]
  244705 Chain Back-up
  244638 Chain Guide / Lubricator (Operator Side)
  063-45853 Idler Roller Assembly
  182129 Bearing - for Compression Roller
  230961 Hinge Set - Lift-off - Left-hand (for front guard door) - machine uses 2 sets
  237224 Hinge Set - Lift-off - Right-hand (for front guard door) - machine uses 3 sets
  357-45955-38 Screw (to install Hinges) - twenty (20) required, total
  257009 Assembly - Motor with Cord
  259060 Solid State Relay

NOTE: A * in the "Spare" column denotes a part that is recommended as a common spare part for this machine. If a number is listed, that quantity is typically included in the New Machine Spare Parts Kit Option available when ordering a new machine.  Trimmer and Coder spare part components with a quantity and * are included only with the respective Trimmer and Coder New Machine Spare Parts Kit Options. (Spare Parts Kit contents are subject to change without notice.)

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