Daikin VAM 1000FAVE, Service Manual

Page: 51 / 84

Troubleshooting SiE71-202
42 Troubleshooting
1.9 Data Transmission Error (Between LCD Remote Controller and Main Unit)
Remote Controller
LCD Display
Error Code
U5
Inspection
5
Unit No.
5
LED Indication Remote Controller
5
Main Unit
5
Error Detection
Method Microcomputer checks if data is transmitted properly between main unit and remote controller.
Error Generating
Conditions
When data transmission is not performed correctly for a certain time period.
Possible Causes
Faulty connection of remote controller cable
Faulty remote controller cable
External factor (noise, etc.)
Troubleshooting
Note: Note 1:
1. Use tester to check continuity of remote controller cable.
Disconnect cable from main unit terminal board and remote controller terminal board. Measure
resistance between wires in cable. Resistance should be
∞
M
Ω
(infinity).
2. Use tester to check voltage at terminal board.
Check with power turned on.
With remote controller cable disconnected, voltage between P1 and P2 on terminal board should be
approx. 16 VDC. If measured value is not approx. 16 VDC, PCB assembly is faulty.
Connect remote controller cable and disconnect remote controller. Voltage at the end of remote
controller cable should be approx. 16 VDC. If measured value is not 16 VDC, remote controller cable is
faulty.
Connect remote controller cable and remote controller. Voltage between P1 and P2 on remote
controller terminal should be approx. 16 VDC. If measured valued is not 16 VDC, remote controller is
faulty.
Check connection of
remote controller cable to
control PCB assembly on
terminal board.
Is
remote
controller cable
normal?
Note 1
YES
YES
Correct wiring.
Replace remote controller
cable.
Possibility of external factor
(instead of equipment error).
Is
connection
cable between
main unit and remote
controller
properly
wired?
NO
(HF008)
NO
P2 P1
(HL032)
LCD remote
controller
Remote
controller
for heat
recovery
ventilation unit
JC J2 J1 F2 F1 P2 P1
Main unit PCB