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

October 17, 2024

Carrier VRF Static Pressure

All ducted VRF systems come from the factory set for 0” of static pressure. As we know from experience, this is not possible when any ductwork is attached. 0” of static pressure is only in a factory setting with nothing attached.


You may be asking yourself “What happens if Static isn’t updated?” When static pressure isn’t set on a ducted indoor unit, this makes the algorithm always operate the fan in the lowest fan speed possible. As you can imagine, this won’t work. So how do we set Static Pressure? This can be achieved on both WIRED remote controls. The programmable controller is not only an easy-to-use thermostat, but also a great service tool as well.


Let’s start with the programmable control first:

40VM900003 programmable (Carrier)

40VM900013 programmable (Bryant)


We need to get into the Service Menu by Holding “FAN” and “BACK” for roughly 3-5 seconds.

White wall thermostat/control panel with digital display and highlighted fan and back buttons

Once inside the service menu scroll down to Page 2 of 3 indicated by the top right corner of the screen. Highlight “Static Pressure” and hit “Menu/Ok”.

HVAC control panel screen showing service menu page 2/3 with “Static Pressure” highlighted.

In the menu use the Up/Down arrows to choose static pressure setting and press Menu/OK to confirm.

HVAC control panel display showing “SERVICE-STATIC PRESSURE” and 0.44 in. w.c., with TEMP UP and TEMP DOWN buttons highlighted

Now on to the non-programmable model.


40VM900002 non – programmable (Carrier)


40VM900012 non – programmable (Bryant)


This model uses a different method to make any advanced settings. First, press any button to wake the controller up and light the screen then press and HOLD “MODE” and “FAN” for 5 seconds to access the Service Menu. You’ll know you’re successful when the display changes to 0 0.

White air conditioner remote with LCD display and labeled buttons, showing MODE and FAN highlighted in red.

The code on the left is known as “1G” and the right as “2G”. Pressing the up and down arrow scrolls through the various 1G codes. Static Pressure is #10 for 1G. Press “OK” to move to the 2nd code. Use the chart below to determine what 2G code should be used then press ok to confirm.

Menu screen for setting IDU static pressure, with a list of values in WC.

To exit back to home screen either wait 30 seconds or press back twice. This applies to both controllers.


Now that static pressure is set in the thermostats you should hear the fans ramp to their appropriate speeds.


If you are ever in doubt about which thermostat you are working with, below is a side-by-side picture to help you figure it out.

Side-by-side programmable and non-programmable thermostat controls with digital displays and buttons

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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