Midea V4 Plus

R410A DC Inverter VRF V4 Plus W Series 50Hz MCAC-VTSM-2016-04
206 Troubleshooting
3.7 H7: Quantity of indoor units decrease error
Note:
1. How to check whether the transformer of IDU is disabled①
The voltage input for IDU transformer is 220V, the voltage output of is AC9V (yellow-yellow) and AC13.5V (brown-brown)
2. How to check whether the 485 communication IC is disabled②
The normal voltage between “P” and “GND” is DC2.5~2.7V, between “Q” and “GND” is DC2.5~2.7V. If the voltage is out of the
normal range, the 485 communication IC is disabled.
* Indoor units should be unified power supply, which can prevent compressor from liquid hammer caused by dropped indoor units
with EXV unclosed.
H7: Quantity of indoor units
decrease error
Communication terminals P Q E
are loose
Fasten the communication
terminals
Yes
Transformer of IDU is disabled①
Replace the transformer
IDU are not unified power supply*
Insure all the IDU be unified
power supply
485 communication IC is disabled②
IDU PCB is disabled
Replace the IDU PCB
No
No
No
No
Yes
Yes
Some IDU are assigned the
same address
Some IDU are power off
Set the IDU addresses differently
Power on all IDU
No
No
Yes
Yes
P Q E
terminals