Fault light on- red LED on PSC (green board) not flashing

The fault light is on so I opened the front cover and I can see that the red LED on the Pump Speed Control board (PSC) -the green board- is not lit or flashing. Looking at the manual, it says that this means that the 'unit is dead' which sounds very very worrying..... do you believe that it could be repaired by the replacement of any parts by a service engineer?

As a remedial measure we put some water on the upper tank but I wonder if we also should reset the manual overheat button, could you advise if this would be the right thing to do? And if so, how to do it?

Your prompt response is much appreciate. Thank you in advance for your help.

Regards

Make sure unit is full.
Check unit has supply to it.
Also there is a fuse on the pump drive board.
If you have the manual reset button you just reset it.
If the pump drive board has blown a fuse.
Check the pump for water inside the connections (from PHE leak)
If everyone put what area they are in their post.
Maybe some one local would reply.
Mike
MGC/H2O
Norwich
Norfolk

Fill the header tank half way, ensure it stays there. Then press the overheat stat reset button. That should resolve your problem