Having it suspended makes sense. I didn't pay much attention when it was all installed, and didn't appreciate how it actually worked. Just assumed the installer knew what they were doing, and it should be good for 5 years. The strange vibration started after 2 years, but it was so occasional we didn't worry about it. And of course it only happened in the summer. Then on the third summer the noise got worse and happened more randomly and the pump failed.

The failure was a bit of a mix of things. Mainly it was slow drips out the front of the unit. I knew I could leave it on for 20-40 minutes on a humid night before it would happen. But a couple of times a small torrent would come out. I assumed the pump  had managed to get some up into the roof, then the let it go.

In the end got up in to the roof and figured out what was happening. Have pulled the drain and pump out and let it was just running into a bucket. So will need to get it sorted before summer.