Possible problem with my shower pump. Turns on randomly

[Amit]

I have a salamander esp 100 shower pump.

Its configured for negative head, even though I have a positive head setup because the response time in +ve head mode is too slow (1sec+ between tap open and pump fire)

The shower head is about 60cm below the cold tank which is in the loft directly above the head. The pump is under the bath which backs onto the cylinder which is in the next room. (pump at base of cylinder but separated by a wall. The pump is fed via a dedicated supply from a surrey flange.

Randomly through out the day/night, the pump will turn on for a few secs then turn off. it probably happens twice a day (random times)....

The Taps arent leaking.

What could be causing this issue?

 

[Fluffster]

The pump is registering pressure changes as a neg head is v sensitive.
Do you have any dead legs or other pipework on the same network before the pump?

Pete

 

[Amit]

not sure what you mean by dead legs.

There is a surrey flange in the top of the tank which feeds the hot side of the hot side directly.

The top out let of the surrey flange goes downstairs and to the loft for expansion.

The cold side is a direct feed from the loft.