Safety check LED flashing on Triton Topaz 100i shower?

My Ttriton Tapz 100i shower stopped heating the water the other day but all other displays controls etc were still working. I checked the thermal cut out and it was open circuit so i ordered one from Triton. After replacing the old one with the new one, turning on the shower now the display doesn't come on and the 'safety check' LED flashes.

This shower was installed before I lived in the house so I dont have the instructions.

Your ideas are appreciated....thanks