Filter-free ultrasonic cool-mist humidifier with a simple power/output knob and exact Honeywell support for little/no mist, reservoir overflow, and hard-water white dust.
Choose the observed symptom, light, code, app state, or output problem.
Visible mist is expected from the ultrasonic HUL535. Honeywell narrows little or no output to five owner-level conditions: no tank water, an unlevel unit, mineral deposits on the nebulizer, a power setting that is too low, or detergent residue left in the tank/base after washing.
Honeywell gives a short, exact HUL535 overflow path: inspect the tank for damage, make sure the Tank Cap is locked tight, and confirm the Tank Cap Seal is present. Those checks should be completed before assuming the powered base itself is leaking.
White dust from the HUL535 is a hard-water mineral effect, not evidence that the humidifier is defective. Honeywell explains that ultrasonic mist can carry dissolved minerals out of the tank and recommends lowering the mineral content of the water, with distilled water giving the strongest reduction in hard-water areas.