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.

Andy Johnson

VRF Tech Support and Quality Assurance • North Georgia, North Alabama

December 17, 2024

VRF Login / Brand Selection (Carrier or Bryant)

Once your Carrier or Bryant VRF system is up and running, there’s one final step to complete if you’re using a Central Controller (sometimes referred to as a Touchscreen). The Central Controller offers various features beneficial to both contractors and end users, including scheduling, adjusting and locking temperature settings, reading error codes, and making minor adjustments.


Let’s walk through the installation process to get started.


As you turn power you will see this screen. Asking to select language.

Carrier login screen with language dropdown set to English and a blue Next button

Select “Carrier” or “Bryant” “No logo” and click “Save”.

Dark interface with Carrier and Bryant logos and a blue “Save” button.

One of the following screens will be displayed depending on the user selection:


Auto Search — The Touch Screen Central Controller can automatically search and connect to the system’s connected units. Devices connected to the controller are automatically searched and brought into the Central Controller / touchscreen.


1. In the main menu, click the [Install] menu icon. You see the word install. Press INSTALL

Thermostat app dashboard showing 0 units running, 29 May, 5:13 PM, with control icons along the bottom.

2. Click the [Auto Topology] button. Then it will start to search for all the units that you have. When it has found all your units you then will hit save.


Make sure you tap “SAVE”

Top-down vehicle installation screen with auto topology list, device icons, and a blue Save button

3. If everything is successful, the home screen should look like this and have all equipment items including Indoor and Outdoor units.

Hospital staff scheduling dashboard on a touchscreen, with a red arrow pointing to the Health icon.

4. You will need to hit INSTALL.


You will then see this screen.

Car dashboard infotainment screen showing radio settings, with a red arrow pointing at the preset list.

5. Tap the name of the unit to update to what you’d like. For example, “Lobby, room number, etc.” Naming a unit by its physical location allows the end user to communicate an issue easier and control certain areas like meeting room when not in use.

Tablet showing an “Auto Topology” form with an on-screen keyboard open and a red arrow pointing to a field.

You will hit the save button and it will be saved.

Computer screen showing a blue “Succeeded” confirmation dialog with an OK button over an Auto Topology page

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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