Anyone got solar panels? why does our system come to life late at night?

[Finbar]

We inherited a solar panel system with the house we bought 6 months ago. No idea how it works really although I've downloaded the manual off the internet.
However, the system is located in a cupboard in our bedroom - and sometime, but not always it starts a purring whooshing noise and generally springs to life around midnight (hence why I'm up now)
Anyone have an idea why?

[PigletJohn]

is it hot water, or photo voltaic?

Post some pics.

[Finbar]

I think hot water but will get pics and the manual I downloaded.
It's quiet now! But it also comes on at. (what seems to be ) random times in the day too

[Finbar]

I posted too soon ...its just started up again!
I think I will start logging the times

[PigletJohn]

I am speculating that it is hot water and you are hearing the circulating pump. I know next to nothing about solar hw. The pump is probably controlled by heat sensors in your cylinder, pipe and panels. I would have though it would start up when the cylinder was cold and the panels were hot.

The installer's name is probably marked somewhere on a label, and in the documentation, so might be worth calling in for servicing or at least a check-over, though some major boiler manufacturers sell integrated systems and will have a list of approved installers.

Water being pumped round is usually inaudible, whooshing noises suggest air bubbles in the pump and pipes. If so, this is likely to be wrong.

[Finbar]

Hello and thanks. It's a DeltaSol BS System apparently comprising 1 store, 1 pump and 3 sensors
I'm getting so fed up with it!