All Models
Indoor Outdoor Unit Communication Error E1 (page 2 of 3)
Note: Terminals may be referred to in one of three ways. 
L, N, S Or L1, L2, S Or 1, 2, 3
Go to ODU and Measure the DC       
voltage between “N/L2/2” and “S/3”              
Black Lead to N/L2/2, Red Lead to S/3
Follow the “1st Steps for DLS Troubleshooting” in the beginning of this guide,        
if E1 is displayed, procedure below.  
Under normal operation voltage will alternate from approximately -50 Volts to +50 Volts.
If your meter has a MIN/MAX setting, we recommend using this. It can quickly show you the 
top and bottom of the alternating range. 
Replace Indoor PCB.
Check the wiring connection 
from indoor terminal to indoor 
PCB. Are they OK? 
No
The value is always positive.
The value is fixed and close to 0. 
The value is alternative from negative to positive. 
Check the wiring connection from outdoor terminal to outdoor 
PCB and wiring between PCB’s if there is more than 1 PCB
For ODU’s with 2 PCB’s,  
main and IPM (Inverter).
For ODU’s with only 1 PCB 
Continued on next page