Daikin VRV IV+ Service Manual page 148

2 | Troubleshooting
2.3.141 U1-19-20-21 – Hz error detection on Power Supply
Service manual
148
INFORMATION
Main, Sub 1 and Sub 2 indications are relevant in multiple outdoor unit
configurations. Main outdoor unit is the unit to which F1‑F2 IN transmission line is
connected. Main, Sub 1 and Sub 2 outdoor units can be identified by field setting
1‑00.
Trigger
Open phase detected by
phase detection circuit.
To solve the error code
INFORMATION
It is recommended to perform the checks in the listed order.
1 Check if the power supply is conform with the regulations. See
4
circuit" [ 356].
Possible cause:
▪ Faulty or disturbance of the power supply (imbalance >10%),
▪ Power drop,
▪ Short circuit.
2 Perform a check of the noise filter PCB. See
Possible cause: Faulty noise filter PCB.
3 Perform a check of the inverter PCB(s). See
Possible cause: Faulty inverter PCB(s).
INFORMATION
If all procedures listed above have been performed and the problem is still present,
contact the helpdesk.
Main error code
U1
INFORMATION
Main, Sub 1 and Sub 2 indications are relevant in multiple outdoor unit
configurations. Main outdoor unit is the unit to which F1‑F2 IN transmission line is
connected. Main, Sub 1 and Sub 2 outdoor units can be identified by field setting
1‑00.
Trigger
Main PCB does not detect
zero-crossing for a certain
duration.
Effect
Unit will stop operating.
"3.12 Noise filter
"3.10 Inverter
Sub error code
19
20
21
Effect
Unit will stop operating.
Reset
Power reset at outdoor
unit.
"4.1 Electrical
4
PCB" [ 298].
4
PCB" [ 274].
Unit
Main
Sub 1
Sub 2
Reset
Power reset at outdoor
unit.
REYQ8~20+REMQ5U7Y1B
VRV IV+ Heat Recovery
ESIE18-15B – 2020.05