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Greek_engineer
24-11-2012, 04:08 PM
Hello my friends!!I want your valuable help.
I have a daikin RX35JV1NB air condirioning and the problem I face is that the a/c is constantly out of operation and having the indoor green led always flashing..
Regardeless of the times I tried to reset it, the problem remains the same..
Having read the service manual,I checked the power supply of the unit and I didn't notice any problem.The manual says that the code (U4) is related with the indoor - outdoor communication.
Are you having any idea about how to find any possible solution?
Thanks in advance...

install monkey
24-11-2012, 04:28 PM
ive had it on a daikin that ran for 6yr ok, then u4. disconnected wire 3 on outdoor, tested 48vdc pulsed signal, had green flashing leds on indoor ,outdoor pcb, turned out to be the outdoor pcb, after swapping indoor pcb as part of the flow chart asked if 48v was present on the signal wire,which it was, isolator connections were proved ok, interconnect cable was proved ok

woolyback
26-11-2012, 05:46 PM
Hello, First of i want to make sure the fault is U4, this is done by using the remote controller, push and hold down the cancel button on the remote controller until (normally) 00 is displayed, now repetadily push the cancel button until you hear a long beep from the fan coil, this will show the exact fault code from the unit. If the fault is U4 then this is a comms fault. normally this is no fault of the equipment but more likley to do with the comms line, i would first check if there is a pump connected or if ther is a break in the cable, secondly iw ould remove the comms cable from the indoor unit and outdoor unit and test between nuetral and the cable that is disconected both ends and see if there is a mysteriuse AC voltage on the coms cable, if there is it will be that voltage that will cause the problem, probably running near another mains cable, move the cable job done. as a suggestion it might be easier if possible to temperary run a cable on the coms line to see if the fault goes or not. if the fault still persists then check with the coms cable disconected the DC voltage between the coms cable and nuetral and see if you see a fluxuating 5-45 dc voltage (you may need to reset the power to see this) if you dont see a voltage then the outdoor board is faulty if you do then it will more likly be the indoor board. though more often than not it is the cable itself.

Greek_engineer
26-11-2012, 11:18 PM
I came back my friends..thanks a lot for your instructions.
a new factor for this troubleshooting is the outdoor green (service) led on the electric circuit board is not flashing.that indicates that the problem probably lies with the outdoor unit...do you know how much the local distributor charges for that outdoor circuit board?
the answer is 290 euro...

install monkey
27-11-2012, 12:36 AM
yep- £230 in uk and £90 for the indoor-carry out the checks that wooleyback mentions to prove it is the a system fault- check the fuses on the outdoor pcb, you have to take the top lid off,remove the plastic lid then to inspect the pcbs theres a few screws to remove , maybe unplug the 4 pin plug for the compressor and unplug the sensor plug, cond fan motor-good luck

Greek_engineer
27-11-2012, 01:33 PM
I do not know if it is worthwhile changing the outdoor circuit border or the whole a/c...since no one knows for a certain if the problem lies 100 percent with the outdoor unit..there is a possibilty to have the both circuit boards (indoor-outdoor)damaged...

Mick13
05-12-2012, 08:12 AM
a trick i learnt from a daikin technician for u4 faults, if your unit has a fan only mode, and when u put it on fan only if the fault disappears and the indoor fan starts up, this indicates that the problem likely lies with the outdoor pcb, as the unit only calls for the outdoor unit when heating or cooling is wanted.

Greek_engineer
05-12-2012, 08:19 AM
It is a very rational answer...thanks a lot..It seems that the unit reads error when it tries to communicate between indoor-outdoor.Setting only the fan operation could be a reasonable way to discover where the problem lies..

install monkey
05-12-2012, 11:08 PM
I tried that on my faulty unit- in fan only,start up indoor, by the time the louvres opened it alarmed,before the indoor fan got powered up- had green flashing light on indoor unit and outdoor indicating comms ok

manosnad
26-05-2013, 03:40 PM
I tried that on my faulty unit- in fan only,start up indoor, by the time the louvres opened it alarmed,before the indoor fan got powered up- had green flashing light on indoor unit and outdoor indicating comms ok

and i have the same problem the outdoor unit is dead no green led flashing my model is rx25jv1nb i look my pcb board and i found dead these ..zd1 <i ve no idea who is the value of this>is not recognise.r11 is burnt r21 and r37 and so transistor voltage regulator 2sc3751 is dead...i replace this but it does not work anything to know for what is it?

AbsoluteWDJ
27-05-2013, 09:01 PM
Hello my friends!!I want your valuable help.
I have a daikin RX35JV1NB air condirioning and the problem I face is that the a/c is constantly out of operation and having the indoor green led always flashing..
Regardeless of the times I tried to reset it, the problem remains the same..
Having read the service manual,I checked the power supply of the unit and I didn't notice any problem.The manual says that the code (U4) is related with the indoor - outdoor communication.
Are you having any idea about how to find any possible solution?
Thanks in advance...

Concentrate on the outdoor fan motor. Power system down for 10 mins, disconnect the outdoor fan motor, check the wiring for fan motor, if ok, connect and power up. See what happens!

RBM
29-05-2013, 01:20 PM
Concentrate on the outdoor fan motor. Power system down for 10 mins, disconnect the outdoor fan motor, check the wiring for fan motor, if ok, connect and power up. See what happens!

Disconnect outdoor fan and compressor - turn power back on see if green light flashes (outdoor board) if light not flashing (and its not comms wire breakdown) fault is with outdoor board. Megga test compressor 10 M to earth limit. Remove fan blade from outdoor fan if motor not spinning freely it is faulty. If you change the outdoor board I would also replace the outdoor fan motor as well
good luck

Dimpman
20-07-2013, 06:39 PM
Do you need to reset units before putting on fan only or if you just switch over they will disappear .? Cheers