Diagnosis
This is almost always a severely clogged air system. The heat pump can't exchange heat efficiently if airflow is blocked, turning it into a slow, cool dehumidifier.
How to Fix It
- Clean the main lint filter (inside the door).
- Immediately clean the secondary condenser filter (blue fins in the bottom front slot) thoroughly under running water as described in the first fix.
- Check and clear the drain pump filter. Open the small kickplate at the bottom front (may require a coin or flathead screwdriver). Place a towel down, unscrew the black cap, and clear any debris from the filter and the pump housing.
If That Didn't Work
The evaporator (inside the machine, behind the condenser filter) may be coated in a felt-like layer of lint. This requires partial disassembly to vacuum it out—a common issue if the condenser filter wasn't cleaned regularly.
Heads Up
Heat pump dryers are inherently slower than vented dryers, but 3 hours is a failure mode. After cleaning, run an 'Empty Dry' cycle on high heat to reset the system's performance baseline.