shower pump

been reading about Salamander pumps we had new bathroom and corner shower fitted. we have had numerous problems with the pump. the company that did the job got both the aqualux unit company and the Salamander engineers out to fix problems to no avail. till finally I got so fed up one blaming the other . the corner unit was removed the pump stayed . the problem is the damn thing kicks in by its self when not in use, now ok you say so what, but its in the loft an none to quiet and at three or so in the morning its a bit scary ! we have now had a separate switch put on so at least we can get a full nights sleep without having to climb in loft to switch it off! Has anyone else had this problem! When its going its great but some times the switch needs to be flicked to get it going.!

Sounds to me like there is some sort of secondary circulation going on causing the pump to switch on. Some houses have a secondary hot water circulation loop installed so that hot water is always available as soon as a tap is turned on, rather than waiting for a long cold deadleg to run through.

If that circuit has been left in place then the circulation it generates could possible cause your problem.

But being just a keen and quite experienced amateur others may wish to contradict

It is not good practice to fit pumps in lofts
It is most likely caused by water movement, most likely on the hot service.
Salamander sell a non return valve that fits on the hot outlet off the pump to prevent the pump kicking in.
Has a non return valve been fitted if not this should sort it.