Cause
Drain pump is working but Drain not detected.
Solution
Connect the drain hose properly.
When checking the rear drain hose, if the drain hose is not connected and is blocked by the cap, water will not be able to drain. Place a basin that can hold 1.5L of water underneath and remove the cap.
Check the Drain hose for kinks or blockages. Check if the drain hose is free of clogs or kinks and is not pinched behind or under the dryer.
Drain pump sump for debris.
Check the Water level sensors.
Make sure the drain hose is properly installed at the back of the dryer and at the stand pipe.
Note: Most heat pump dryers have 2 ports at the back of the unit. One port is for the drain line and the other is a factory service port. Make sure the drain hose is connected to the correct port!!!
Picture with drain hose connected…
Here is another example showing a slightly different layout but the principles are the same…
If you need to order a new service port cap in the case that the customers is broken and leaking, the part number is shown below (3920ER3002A)…
Next, make sure the drain is properly installed at the stand pipe at the wall. Failure to install properly will also cause issues. Below Shows proper installation…
Here is an example of improper installation…
If the drain is improperly installed like the above picture, water can/will fill into the washing machine while the dryer is operating…
If no drain installation issues are found then continue troubleshooting below…
Picture of the drain sump cover removed and the bottom of the cover:
The water level sensor receives 12Vdc from the main board, and when water reaches the probes, the voltage will drop to let the Main PCB know the pump needs to activate. If there is no 12Vdc from the Main PCB replace the Main PCB. Example from WKHC252 check your machines individual diagram.