Jonathon Pullen

Technical Services Manager Gulf Coast District

August 9, 2022

The Infamous E1: Part 2

E1 fault code on Ductless equipment is communication fault between the indoor and outdoor units.


When the E1 code shows up on the indoor display board, the coms have failed and the systems have stopped working. Until this problem is fixed, the system will remain off.


Start trouble shooting this problem at the outdoor by taking a DCV reading on L2 and S or 2 and 3 depending on how the unit is labeled. Take a DCV reading on the terminals for the indoor unit wires.

Good coms volts look like + to – 50 volts fluctuation.



If you see a fixed negative or a small amount of fluctuating volts staying in the negative, the indoor board has failed. If you see a fixed positive volt reading or a fluctuating positive reading the outdoor board is bad.


The reactor also needs to be checked. Check the reactor with the wires off and ohm it out. The ohm reading should be .1-1 ohm and should not be grounded.

< Older Post Newer Post >

More to Explore

The EPA 608 is Changing!

September 16, 2026
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. 

DLS A2L Dissipation Error Codes

By Jesse Van Atta • September 16, 2026
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.