We've been using a Hitachi Split Inverter Type Air Conditioner for over a year now, and we recently had it service cleaned about three months ago (the recommended schedule is every eight months).
However, we recently noticed that some water droplets are forming inside the air conditioner: the first is on the metal grill-like section behind the two removable air filters, and the second is on the ceiling of the opening where the air is blown.
Another problem we noticed is that after a few days of being turned on, the air flow becomes irregular, as if the engine is having difficulty blowing air (e.g. instead of a steady "whiiiiirr," we get a "whirr... whirr... whirr...").
Based on the manual, the only maintenance we are allowed to do is just to remove the two air filters, rinse and dry them, and then put them back. Any other maintenance needs to be called on their service department. This seems to be so the warranty does not become invalid and for inexperienced users to avoid damaging the units.
Because of how limited the recommended maintenance is on the user's side, the only option we've tried is to just turn off and unplug the unit for some time (e.g. overnight or for two days). This seems to resolve the issue temporarily, but it keeps coming back.
Our first hunch is that some cooling and drain parts have frozen over, which is causing some water to collect, but water leaks very rarely and we only keep our unit in Dry mode. The drain tube needing cleaning might also be a possibility, but we haven't checked yet because, as mentioned above, we recently had the indoor and outdoor units service cleaned about three months ago.
Any idea as to what could be causing water droplets to form despite the unit being in Dry mode, and any advice on our situtation?