Daikin not working

[leah]

I am not sure if Im posting in the right place but my daikin inverter with outside unit model = RXS71BVMA and indoor unit model number FTXS71BVMA was full of ice and I mean hard ice from recent bad weather in Australia. The only way to get rid of ice was to poor warm water over it. we left it for a day befoe turning back on and now the green light flashed and nothing was working. we turned it off at the power box and the light isnt flashing but its not doing anything at all, the outside unit isnt even starting up. I can put it in air con mode and it seems to work but still not the outside unit. When I checked the code on my remote it was U4 System Transmission between indoor units, and I dont know what that means?? Can anyone help, its soooo cold in Australia I want my heating back!

[ktm]

Are u sure there are no breaks in the cable? Did u check the fuses in the outdoor unit?

[leah]

please dont think im stupid lol BUT I dont know where to look on the outside unit for those things or even what im looking for?

[Crash Pilot]

Leah

Are you a tech or a customer.

If you prove to me that you are a Tech then I will tell you what is wrong with your unit.

If you are a customer then I would suggest that you get someone out that is a Tech because of the dangers associated. Even with the power off the outdoor unit can still have power on it due to the capacitors.

[leah]

hi there no im not a tech thats why I didnt know where the fuses were, I did think I shouldnt be looking into any of it anyway just in case it voids my warranty which they said it could be covered. I have a tech guy coming and he said it sounds like I need a new pcb i think it was, thanks anyway just thought it might have been something simple guess not

[Crash Pilot]

Most likely PCB or Fan motor. Fan motor can drain power from PCB if tight. This will cause u4 .
Tech will be able to test this.

Cheers

[Peter_1]

U4, how to check fan motor:...then you must check additionally the blinking LED under the cover (where wires are attached) of the outdoor unit and see if this LED blinks or if it's steady.
You first have to check with fan and then a second time disconnecting the fan on the PCB (left undercorner on the PCB) after shutting Off main supply to the outdoor unit of course.

[weidit]

Sorry Which unit was covered in Ice? Bad weather of ice buildup on pipes/coil?

[Peter_1]

Correcting, testing this led of course while unit is connected to the mains.

[Crash Pilot]

I would place money on fan motor seizing. This will drop airflow across outdoor coil and cause premature icing while indoor on heating.
When motor failed completely draining power from outdoor PCB and causing U4.
I would check for led's.
If no led's turn power off / disconnect motor/ Turn power on and see if you have led's back. If yes then motor is problem.

To test motor disconnect from PCB /Take fan blade off and spin shaft on motor with fingers(should get about 1 1/2 revolutions. If you dont and motor is notchy them this confirms motor is faulty. Must take off blade or there is too much leverage to tell. Also never disconnect motor or connect while power is on. If you dont zap yourself you will blow the PCB.

[Mentallist]

Spinning the motor by hand will not confirm failure, design of the motor means that it does not spin freely. Only way to confirm motor failure is by resistance test. Service manual explains test procedure.

[weidit]

As above would try to check motor first then maybe board. Should say inside cover how check fault via outdoor pcb board led lights.

Regards

[Peter_1]

...
I would check for led's.
If no led's turn power off / disconnect motor/ Turn power on and see if you have led's back. If yes then motor is problem.....

I can be wrong but according to what I've seen in the field, its s blinking or steady LED, not led off.
Correct me if I'm wrong, never too old to learn .

[Crash Pilot]

Spinning the motor by hand will not confirm failure, design of the motor means that it does not spin freely. Only way to confirm motor failure is by resistance test. Service manual explains test procedure


Spinning the motor by hand will confirm the fault. Majority of motor failures on this model are due to failed rear bearing. When you spin the motor staff it will spin up to one and a half turns and feel slightly notchy. When the motor bearing is faulty the motor will be locked and very hard to turn.

Agreeded that metering the motor out is important however with a u4 it is usually associated with a locked motor and not a electrical problem with the motor.
This is based on what I have found however feedback from everyones experiences is what we need on this forum.

[Mentallist]

Was there not an issue with 4 way valve coil causing u4 errors on these types of units. I seem to remember this was a possibility

[ANDREASGR]

hi
u4 contact problem with internal replacement outdoor unit and pcb control cable communication