I have a sentinel kinetic V fitted in my loft, the system is 10 years old. This month it has started purging at around 8.30pm and this goes on for around 5 hours. It is extremely loud and can be heard on the ground floor. I have previously read about changing the settings, but I have noticed that the screen on the front of the unit is blank. It lights up when buttons are pressed, but there is no visible text. 
Does anyone have any ideas as to how I can sort this? We have resorted to turning off the unit at night now due to how loud it is. 
 

Thanks in advance! 

factory re-set and reprogram?

Have you spoken to Vent Axia? obviously unit is out of warranty, but they may be able to advise.

 

Sounds like the PCB could be bust to me.