Our number 1 heatpump decided to cease operation the other day...
Both the fans came on but no clunk and rumble from the compressor.
Getting it apart was a little interesting, needed a posi drive screwdriver almost 200mm long.
The culprit turned out to be a crimp lug that got a little loose, got hot and turned into a fuse.
Fix was pretty quick with a new lug.
I took the opportunity to vacuum out dust and cobwebs while I was at it. Pix below for interest.
Machine circuit diagram.
Electromechanical controls of mode and temperature.
Start and run caps for the fans.
The third party condensate pump I fitted to pump out the unit into a bucket or the sink.