If installed in an appropriate environment, the drive requires very little maintenance. This table lists the routine maintenance intervals recommended by Daikin.
Drive Module Fan Replacement
The drive module fan cools the heatsink. Fan failure can be predicted by the increasing noise from fan bearings and the gradual rise in the heatsink temperature in spite of heatsink cleaning. If the drive is operated in a critical part of a process, fan replacement is recommended once these symptoms start appearing. Replacement fans are available from Daikin. Do not use other than Daikin specified spare parts.
Source: Daikin (oslo.daikinapplied.com)