Heat pumps become louder and louder after a few years. This is often because the fan motor bearing suffers damage after 5 to 10 years. As a result, the outdoor unit gets noisier, runs unevenly, and eventually sounds like a truck engine outside the house.
Bearing failure is rarely repaired, as the process is labor-intensive and requires specialized skills. Heating technicians typically replace the entire outdoor unit motor, a job that can easily cost between 500 and 800 euros in Germany.
However, this task is very easy to perform yourself!
The entire replacement job takes about 30 minutes.
Repair your heat pump
for €140
Replacement parts can be purchased cheaply outside of the manufacturers’ official distribution channels. In my case (Fujitsu Waterstage WOYA100LFTA), the replacement motor cost €101.99; including shipping from China, the total came to €139.52.
Find your motor
You can identify the motor model by opening the cover of the heat pump’s outdoor unit. In my case, it was model MFE-60TVT, which was available at a low price on AliExpress.com.
Opening the heat pump
To access the motor, you need to remove the heat pump’s covers.
Caution: Do not disconnect or damage the refrigerant lines!
Removing the fan propeller
Next, the fan propeller must be removed. In my case, it was attached to the motor shaft with a screw.
Replacing the motor
The motor can now be replaced with a direct swap. The replacement motor fits the existing mounting points perfectly, and the cable connects to the original terminal.
Enjoy the silence
Finally, run a test to verify the result. The heat pump should now run quietly and smoothly again, just like on day one.
I recommend carrying out the DIY repair in the summer; that way, there is enough time to call in a professional if something goes wrong.