How csn I fix it?

I have a varispeed newteam pump which feeds 2 showers, it is about 6 years old.

Just recently when I turn the shower on the pump does not come on, if I tap some times it starts up, but then next time I use it the same problem.

I am a electrician so I have checked for any loose wiring but all is ok.
Any idea what to do could it need lubricating ??