It is a good practice to make sure all of your dip switches are set to the factory position on all of your flow selector boxes during installation. If the dip switches are not set in the factory position you will have L11 and E17 error codes to follow. You can verify the factory dip switch settings by looking at access door on the flow selector box. The L11 and E17 error codes can also be caused by wiring issues, good wiring practices can prevent having problems.


Changing dip switches on your flow selectors is not necessary because all of your flow selector addresses and port numbers are set using and codes 00FE and 0105 on your thermostat. Making sure your flow selector address and your flow selector port address is correct will make the start up process much easier. If care is taken and you have a good understanding of the wiring and installation of a VRF system the start up process can be close to seamless.


L11- Detected indoor unit address, Flow selector unit not connected.


E17- Communication trouble between indoor unit and flow selector unit.

Once you have logged in, you will need to save the equipment current configurations by choosing: “SAVE CONFIGS TO A FILE”. Align the arrow on the SAVE CONFIGS TO FILE option and press ENTER. Then press ENTER to make the STOP flash, use the UP or DOWN arrows to change the STOP to START and press ENTER. Once this is done, Choose Option 5 to UPGRADE SOFTWARE. Then scroll down to “FIND APPLICATION FILE” and press ENTER to change NO to YES.

Blue screen prompting “ENTER PASSWORD” with masked password entry “1***”

Then press ENTER to choose the USB Product Folders:

System update screen showing file update progress, completion message, and boot log text.

Then select the Product Software: Once selected press ENTER.

Close-up of a white screen showing blue text: “LC PRODUCT SOFTWARE” and two numbers.

Austin Caldwell

Technical Services Manager North Georgia District

December 14, 2023

Circuit B Has No Run Hours

This was a call we got through our Tech Service line. This was on a 48A series unit that was about a year old.


We worked through a few items and ended up concluding making a site visit this is what we found on site.


Troubleshooting Process


On our 48/50 A and P machines they are more than just a standard package unit. In this machine, in particular, When the B circuit Started the compressor fired up but you heard an audible groan from the condenser motors. This started the troubleshooting processes


  • dropped a side panel on the V side of the coil to access the motors.
  • Used lockout Tag out process before unhooking fan motor wiring.
  • Verified the ohms on both fans and made sure there wasn’t a ground issue or locked-up motor.
  • Then worked our way to the VFD. After reinstating power, verified the VFD was getting all three legs of power in.
  • We tested the fans using the service test mode on the Comfort link.


This is where we found the issue two legs on the VFD were sending power. We had one leg with no power. On this job, after tacking the wiring on a 48/50 the VFD is in the cabinet behind the Condenser but the wiring then goes to the control cabinet where it splits. This is where a loose wire was the problem.



This is a great look into breaking down a problem. This issue we broken down into 3 parts: high voltage, control voltage, and mechanical. This is always a great thing to do when you’re looking at a problem. This allows you to not get overwhelmed. Breaking down the problem into these distinct sections helped in isolating and resolving the issue efficiently, demonstrating the effectiveness of a structured approach to problem-solving.

Disclaimer: The technical statements, information and recommendations contained herein are believed to be accurate as of the date hereof, but Mingledorff’s does not make representations or warranties, express or implied, as to its accuracy, its completeness, or the results to be obtained. The information is being provided for informational purposes only and is intended for use by persons having adequate skill and expertise regarding the proper selection, use and application of the products and recommendations and at their own risk and discretion.

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