Salamander pump not working

[AmyNaught]

I’ve got a salamander pump on my shower which has always had issues with air locks but normally we run the sink tap and it triggers it on.

the last 2 days we can’t get it to fire on at all. I’ve checked the fuse and that’s fine then was going to try cleaning the filter but can’t figure out how to ensure I’ve turned off the inlet and outlet pipe to remove the silver bits (novice here)

appreciate any advice.
Thanks

 

[just pumps]

The black plastic parts on the end of the flexis are the isolation valves. Open when screwdriver slot in the middle is inline with the pipe and closed when slot is across the pipe.