Every now and then my shower issues a trickle of water from the head - I hear it hitting the bottom of the bath. This lasts about 10 or 20 seconds. And quite often I notice that it's dripping at about a 10 second frequency. The shower is fed from cold and hot water storage tanks. Neither are under mains pressure. The shower control unit is in the attic, next to the CWST, with a run of about 5 metres of pipe to the bathroom ceiling, and about 1 metre drop to the shower head.
There seems to be no regularity to the symptoms, but I have noticed that it's dripping rather more often now. The shower was installed 3 years ago. I noticed the occasional trickles shortly after it was installed, then these appeared to stop, and now they've started happening again.
Anyone any ideas what is causing the trickles and dripping? Could it be a thermal effect of the attic heating and cooling (though the processor is covered by an old duvet for frost protection)? A 'trickle event' has just happened, and it's dripping a bit now, and the attic temperature is 9c.
Greateful for any thoughts and comments!