F9 fault code on Glow-worm Flexicom?

[DomHeating123]

Just received a call for a third time for a glow-worm flexicom going out on F9 fault code. First time I went to it I reset it and fired up no bother, second time I read up about faults related to it such as pressure sensor so I drained the boiler out of relief valve pressure readings okay on so refilled and boiler ran okay, this the third time now any ideas?

 

[lightning]

If pink pressure sensor then I would replace plus pump up expansion vessels

 

[DomHeating123]

I pumped up the vessel and removed and cleaned sensor, was working fine but it conked out overnight again, its just a black pressure sensor, should I still replace?