Shower makes a 'thudding' noise when power is turned on.

I recently replaced an electric shower and everything seems to work fine.
Small 'problem' occurs when I pull the power cord to turn the shower on. I hear a kind of 'thudding' noise coming from the shower (or pipe). This doesn't happen every time but quite frequently.
As the shower can only run water when the power is turned on, could this noise be the water pressure released as, after the noise, the shower-head trickles momentarily.
More to the point, is this something to worry about?
Thanks.

Sounds like your new shower may be a little more powerful than the old one & you may be experiencing a little `water hammer`. Don`t know where your pipes to the shower are located but it would seem that they need to be secured a tad more.

It sounds like the inlet solenoid is opening momentarily, when you energise the supply to the shower, and that the sudden shutting off is betraying a lack of pipe clips (as per Bg's post).

If the shower is designed to do this then I don't know why; alternatively it's faulty, but I doubt that.

The solution is to trace the pipework that supplies the shower, and install pipe clips where you're able to.

Thanks for replying.

There are very few clips on the pipe so i'll sort that out soon.
Thanks for the advice.