said by Kearnstd:
I honestly have never thought a UPS could get that dusty inside. I know I have to clean my PC. I check the air intake filters every few months as well.
It's a double-conversion UPS, which means it dissipates heat all the time even when not working off the batteries, therefore there are two fans that are always running.
Quite different from typical "line interactive" or "standby" UPS units, which only run on inverter when there is a power failure, and either have no fan at all, or a fan that only runs when on battery. Those don't really accumulate any dust.
This UPS was left on the floor and pretty much neglected for years. The amount of dust inside it was absolutely incredible, the heatsinks were almost completely clogged with dust.