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Brett Stewart

VRF Tech Support & Equipment Verification Southwest District

Toshiba/Carrier U-Series Installation and Troubleshooting: L11 and E17 Error Codes

Installation of a heat recovery VRF system allows multi-zone heating and cooling. A heat recovery system allows you to heat and cool at the same time. One room can be heating and another room can be cooling allowing comfort for all occupants in the building.

Proper Installation is critical with VRF systems. Paying close attention to your wiring, dip switch settings, and code settings and thermostat programming is very important. Having a clear understanding of wiring diagrams and initial installation procedures is a must.

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.

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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