Daikin UF fault code

[deyna]

Help. I have a Daikin 3 phase twin-split system bringing up a UF fault code instantly when switched on. It's been running for 10 years, have checked interconnecting, remote, external pump, Daikin tell me one of the PCB's is down either on one of the indoor units (cassettes) or on the outdoor. Daikin can't tell me which one and say there's no way to test them, it's pot luck. Please help.

[Crash Pilot]

Whats the model number?

[brunstar]

i have had this before and it was induced voltage on the interconnecting cables between the indoor and outdoor, measure this voltage and you will probably find it is higher than 50v dc

[Crash Pilot]

Best way to determine.

System is just 2 indoor units connected to an outdoor unit. eg ( 4hp X 2 indoor ) - (8hp outdoor)

If you want to find faulty PCB.

Disconnect communication on one unit at a time. This will give you electrically a 4hp indoor connected to a 8hp outdoor. If the system still has fault try doing same to other fan coil. If problem fixed then previous indoor PCB faulty. If still have problem then check outdoor PCB or outdoor to indoor wiring.

[deyna]

Thank you my friend, get a job with Daikin, you've been more help in one answer than I've ever got from Daikin, all I got was one word answers. Will let you know how I get on.

[meab]

Hi according to the below chart it seems you got your wires crossed




DAIKIN MALFUNCTION CODES
Code Place Description
AO Indoor Error of external protection device
A1 Indoor PCB defect
A3 Indoor Malfunction of drain Level control system
A5 Indoor Freeze-up prevention
A6 Indoor Fan motor lock, Overload
A7 Indoor Malfunction of swing motor flap
A9 Indoor Malfunction of EEV
AF Indoor Drain level above limit (clogging)
AJ Indoor Malfunction of capacity set device
C3 Indoor Malfunction of drain thermistor
C4 Indoor Malfunction of liquid pipe thermistor
C5 Indoor Malfunction of gas pipe thermistor
C7 Indoor Lower louvre limit switch/motor
C9 Indoor Malfunction of air thermistor
CC Indoor Malfunction of moisture sensor
CA Indoor Malfunction of discharge air thermistor
CJ Indoor Malfunction of remote control thermistor
CE Indoor Malfunction of radiant heat sensor
E0 Outdoor Activation of outdoor safety device
E1 Outdoor PCB defect
E3 Outdoor Activation of high pressure switch
E4 Outdoor Activation of low pressure switch
E5 Outdoor Activation of compressor over heat protection
E5 Outdoor Compressor motor lock
E6 Outdoor Compressor start up error
E6 Outdoor Standard compressor lock/overcurrent
E7 Outdoor Fan motor lock, Overload
E8 Outdoor Inverter input overcurrent
E9 Outdoor Malfunction of EEV
EA Outdoor Four way valve defective.
F3 Outdoor Abnormal discharge pipe temperature
F6 Outdoor Refrigerant overcharged
FC Outdoor Low pressure drop.
H3 Outdoor High pressure switch defect
H4 Outdoor Low pressure switch defect
H6 Outdoor Compressor motor position detection sensor error
H7 Outdoor Fan motor position detection sensor error
H8 Outdoor Current transformer error
H9 Outdoor Malfunction of air thermistor
J1 Outdoor Malfunction of pressure sensor
J2 Outdoor Current sensor malfunction
J3 Outdoor Malfunction of discharge pipe thermistor
J4 Outdoor Low pressure saturation thermistor
J5 Outdoor Malfunction of suction pipe thermistor
J6 Outdoor Malfunction of heat exchanger thermistor
J7 Outdoor Malfunction of heat exchanger liquid thermistor
J8 Outdoor Malfunction of liquid pipe thermistor
J9 Outdoor Malfunction of gas pipe thermistor
JA Outdoor Malfunction of discharge pipe pressure sensor
JC Outdoor Malfunction of suction pipe pressure sensor
JH Outdoor Malfunction of oil temperature sensor
L0 Outdoor Malfunction of inverter
L3 Outdoor Electronic component box overheat
L4 Outdoor Inverter cooling defect
L5 Outdoor Comp motor ground fault, Short circuit
L6 Outdoor Compressor motor grounding/short circuit
L7 Outdoor Total input overcurrent
L8 Outdoor Comp overload, Motor disconnected
L9 Outdoor Compressor lock
LA Outdoor Power unit malfunction
LC Outdoor Transmission between inverter & outdoor
P1 Outdoor Inverter over ripple
P3 Outdoor Thermistor abnormality
P4 Outdoor Power unit humidity sensor malfunction
PJ Outdoor Failure of capacity set resistor
U0 System Shortage of refrigerant or EEV failure
U1 System Negative phase, Open phase
U2 System Power supply insufficient
U3 System Wiring check operation not executed
U3 System Mismatch of indoor and outdoor units (Split only)
U4 System Transmission between indoor units
U5 System Transmission to remote controller
U6 System Malfunction transmission outdoor to BP unit
U7 System Transmission between outdoor units
U7 Outdoor Malfunction between outdoor boards(RMX/RX RK)
U8 System Transmission between master & slave R/C
U9 System Transmission error between indoor to outdoor
UA System Excessive number of fancoils
UC System Address duplication of central controllers
UE System Transmission error between indoor & central
UF System Refrigeration system not set/wiring - piping
UF System Terminals 1 and 3 crossed (Split/Skyair)
UH System System error, Refrigeration system set up
M1 System PCB defect
M8 System Transmission error between central controllers
MA System Improper combination of optional controllers
MC System Address duplication, Improper setting
64 VAM Indoor unit air thermistor error
65 VAM Outside air thermistor error
68 VAM
6A VAM Damper system alarm
6A VAM Damper system and thermistor error
6F VAM Malfunction of remote controller
6H VAM Malfunction of door switch or connector
94 VAM Internal transmission error
Grey fault codes, system still runs, but check ASAP

[Crash Pilot]

meab

That is correct on some systems however this system is a little different. We have 2 fancoils that operate as one. They share the one outdoor unit and cycle on/off at the same time. They can't cycle independently. The controller wires to the first unit and controls the second unit through the no 2 wire on the interconnect that daisy chains between the 2 units. Wire go from out to 123 on first indoor and then to 123 on second indoor. Cant wire both fancoils direct from outdoor. Won't work. Unit will automatically set up twin setting on power up.

[Matt1982]

Hi Deyna

Check there is nothing wired in to terminals 1&2 ie condensate pump. I have seen this cause this type of problem as Terminal 2 is neutral on the newer daikin units and control/data on older units. If somone has changed a pump recentley they may have wired it incorrectly.