Pump fires up after turning off.

Hello....
I have a Showermate 1.4 bar Twin pump which pumps to shower, toilet and taps upstairs and taps/toilets downstairs. The pump used to power up briefly when all taps were closed but I narrowed this down to a dodgy ball valve in the upstairs toilet so replaced this and the problem stopped. However, since then when turning a tap off (any tap), the pump shuts off but gives about 5 quick bursts of power. I am guessing this may have something to do with air in the system?? I have tried running all taps for a few minutes to see if this could be flushed out but the problem remains. Any suggestions greatly appreciated.
The pump is located on the floor next to the hot water cylindar in the airing cupboard.
Many thanks in advance,
Joe

do you have any dead legs anywhere.

Or a tap or cistern (wc) you haven't used for ages?

Thanks for the replies. All taps and cisterns are in use. I'm afraid I don't know what a 'dead leg' is, except for the sort given out at school !

I have managed solve the problem though. I turned off the cold water, drained it down with a downstairs tap, then turned it back on. I think this pumped all the air out including the bit which was trapped. Tested a few taps now and everything seems OK, touch wood !

It seems I was too hasty, the problem is still there. Strangely it doesn't occur everytime I turn a tap on/off.
In response to the previous comments, there are no taps or cisterns which have not been used for ages and I do not know what a 'dead leg' is to comment on this.
Any suggestions most appreciated.
Many thanks,
Joe

Additional information on problem:
Occaisionaly I hear a low vibration from the airing cupboard a minute or 2 after these quick bursts have happened but cannot pinpoint exactly what this is from.