Toshiba VRF system

Good everybody! I'm Charles
I just inspected about 102 outdoor VRF unit and majority of the faults is BAD FAN IPDU.
Please can anyone one tell me the reason most of the FAN IPDU are bad? Or can not servicing the units caused the fan IPDU to go bad?
I'm not familiar with VRF System. Thanks!

If the IPDU pcb heat sinks have come loose ir cooling fans clogged then pcbs can fail.

Manual here might help you.... don't know your model number.

https://www.google.co.uk/url?sa=t&so...U33rE5mGg2ClKn

Thanks Engr. Brian