Shower pump problems

[rogerrog]

Hello all, I have installed a showerforce 3 bar pump in my bathroom due to lack of water pressure. The pump works really well and pumps out great. The only thing is that when the pump is not in use (plugged in) it switches on and off constantly unless I switch it off. This is a real pain, as obviously cannot keep on switching it on and off before/after use. As far as I am aware it doesn't have any non return valve's on it. I have not installed any. I am in doubt as some ppl say it could be the flow switch or the installation of a non return valve! Pls could someone help!

Thanks guys!
Roger