Daikin LC fault.

Hi guys,

Recently i was given a job to finish for a colleague as he is away on holiday. The job was to install a new Inverter PCB into a RZQ124KV4A Daikin ducted system. He had already installed a new compressor but the board wasn't ready at the same time. So i guess the compreaaor had failed and he thought best he replace both (his phone is off so i cannot reach him). I replaced the inverter pcb and also he ordered the small control pcb with the LED and test buttons etc. Replaced that also. When i powered up the unit i am still getting an LC fault. Reset the unit a few times and fault remained. Phoned daikin tech support and he said to check the outdoor fan motors. Checked them and found that one motor has failed with no resistance between the blue and orange cables.
Now here is my problem. I unplugged both motors but i am still getting the LC fault. My concern is that i have damaged the new pcb by installing it with the old faulty motors. Can anyone advise? Should i replace motors and pcb or just motors. Please note that i have already used up quoted time and parts.

Thanks.

LC is a communication fault between main PCB and invertor PCB. Have you double checked all connections are correct and plugged in? Any fuses blown on the PCBs ?

If I remember correctly the fan motors are dc and unless they are operational can cause fault codes.

Check with the manual on how to check the motors.

A faulty motor shouldn't damage the pub.

I know our Daikin units here if a fan motor blows it takes out the PC board as well. Causing outdoor pc board error codes.

if you just replace the board the old fan motors will take out the new board as well.

if you have confirmed that 1 fan motor is not working. I would replace both fan motors and put a new board into it.

For some reason Daikin knows of this fault and haven't corrected it. Just seems so stupid that when a Dc fan motor goes down it blows the board. We find that moisture gets into the wires going into the fan and causes the short. They need to either insulate the wires better or stop that boards blowing when a fan motor dies.

Had this happen last month, faulty fan took out pcb, replaced faulty fan motor and board, issue sorted.

had a similar problem after changed a pot and inverter PCB turned out there are 2 screws that fix the inverter PCB in place that make part of a circuit. found the screws put them in and ran sweet as

You will have to replace both the motor and pcb as the defecective motor had damaged the pcb also

Are there any dip switch settings on the old pcb that will have be repeated on new for it to work correctly? When changing pcb's before I have had to remove the memory chip from the faulty board and move to the new 1 to carry over the settings set on controller... Just a thought though