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.

Brett Stewart

VRF Tech Support & Equipment Verification Southwest District

February 19, 2025

Ductless Systems: Solid vs Stranded Wire

There are many different options and advantages to using a ductless mini-split system. From new construction installation to a retrofit application, these systems can be a solution for your heating and air-conditioning needs. There is no duct work needed for these systems allowing them to be installed almost anywhere without any major installation issues.


When installing these systems, it is highly recommended to run 14/3 stranded wire. Running stranded wire can prevent wire breakage and communication issues. Solid wire can break if installed incorrectly and cause communication and power issues with your system. Stranded wire is a lot more flexible and pliable with several soft strands of copper wire versus one hard copper wire.


Troubleshooting solid copper wire can be tricky. A solid copper wire that is partially broken can still read continuity when checking it with a volt meter. A lot of time, effort, and energy can be spent on a job troubleshooting power and communication issues due to the installation of solid wire. Making it a rule to run stranded copper wire on all ductless systems can save a lot of time and aggravation.


Most of the 14/3 AWG stranded copper wire can be purchased at Mingledorff’s and several other HVAC suppliers.


38MARB


Outdoor Unit Single Zone Ductless System


Sizes 06 to 36


Power and Communication Wiring: The main power is supplied to the outdoor unit. The field supplied 14/3 power/communication wiring, from the outdoor unit to the indoor unit, consists of four (4) wires and provides the power for the indoor unit. Two wires are high voltage AC power, one is communication wiring and the other is a ground wire.


CABLE SIZE REMARKS


Connection Cable 14AWG 3 wire + Ground 1Φ 208/230 V

(Stranded wire is recommended)

White outdoor air conditioner unit with a large front fan and blue logo on the right
White wall-mounted air conditioner unit on a plain background

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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