• Step1 – turn blower and air lock switches to the off positions.

  • Step2 – Turn Speed control switch to the MANUAL position and the Speed Dial to 100%.

  • Step3 – Go to the blower and open the brass bypass ball valve

  • Step4 – Go back to the control box and turn the blower switch to the HAND position which will start the blower.

  • Step5 – To the blower and watch the PSI gauge, then close the ball valve and the PSI gauge will rise quickly, once the gauge reads 10 PSI open the ball valve, and let the blower recover.  Repeat this process until the plug has been alleviated, and the system is running free.

  • Step6 – Once the system has been un-plugged, return all the switches to their normal state: Blower and Air Lock switches in the AUTO position, and the Speed Control switch in the AUTO position.  Then restart the dryer in the normal operating procedure.​

If the system plugs repeatedly, you are losing capacity somewhere, and you should call JPS to help troubleshoot further.


  • When a system is surging, it does not have enough capacity.  Surging happens when the system has corn going up a vertical pipe, and at a certain height the corn collapses from not having enough cfm to overcome the PSI. 

    If your system is surgin, you are either losing air somewhere, or there needs to be an adjustment to the VFD to give you more CFM at the top end.  Call JPS and we will walk you through this VFD adjustment. 


When your airlock is not starting, check the contactor inside the Vari-Air control box and see if the overload has been tripped from over-amps. 

  • To reset the overload press:  the RED button on the overload until you hear a click.  This is the overload resetting. 

  • Test run the airlock: Sometimes when the air lock has been sitting in condensation, it can cause rusting from the vanes to casing.  The airlock will need to be broke loose before operation can continue.  This is usually done with a pipe wrench on the opposite of the drive end. 


If you are losing capacity in the control air tubing between the blower and the control box. 

  • Check PSI gauge: There is a PSI gauge on both the blower and the control box.  These PSI’s should be reading about the same. 

    • If there is over a 1 PSI difference in the gauges you need to see where you are losing air.

  • Check the push-in fittings on the blower and control box, and tighten the connections

  • Re-cut the control air tubing on the end, and try to re-connect to the push-in fittings.


  • Check if you are losing air from anywhere.  The air lock can have air bypassing through it, if this is the case you will need the air lock to be rebuilt.
    • If the system is running corn, check the condition of the corn. If the corn is cracked and you are now moving smaller materials than corn which requires more pressure and amps.


  • When the VFD is protecting the motor it will fault out when the VFD sees non-standard voltage. 
    • If the VFD faults there will be a fault code on the keypad that describes why the system faulted. 

    • To reset this fault, hit the Stop/Reset red button on the keypad.  This will reset the drive. 

      • If you have the blower and air lock switches in the AUTO or HAND position you will need to switch the switches to OFF, and then back to what they were originally before the fault.


When a system is overloaded by too many amps, the VFD will trip out and have a fault code of OL on the front of the keypad. 

  • To reset the fault code hit reset on the front of the VFD keypad.

  • Check the system to see if the intake air filter is plugged.  If the intake air filter is plugged there is not enough air intake, and the system will overload.

  • Clean out the intake air filter.  Remove  the filter from the intake muffler stack and used compressed air to blow from the inside out on the filter element.

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