MCAC-VTSM-2015-10      R410A All DC Inverter V5 X Series 50Hz 
Troubleshooting 139 
4.3  E2: Communication error between indoor units and the master unit 
The error will only display on faulty slave unit, all the ODUs will be on standby. 
 
 
   
E2: Indoor units and outdoor unit 
communication error 
Communication wires P, Q, E are 
short circuited or disconnected 
(Measure the resistance among P Q 
and E, the normal resistance between 
P and Q is 120Ω, P and E is infinite, Q 
and E is infinite.) 
Reconnect the communication wires 
Communication wires are not 
connected in series 
Interference from high voltage lines 
(voltage over 220V is high voltage 
Communication wires are close to an 
electromagnetic interference source. 
Such as transformer, strong 
Remove the interference source, or use 
device to shield the communication wire 
The length of communication wire is 
over 1200m 
Reduce the wire length to less than 
1200m or strengthen the signal 
Connect the communication wires in 
series 
Ensure the communication wires and 
high voltage lines are separated 
Outdoor main PCB is damaged 
Replace the outdoor main PCB