Steam / Reapted flashing light

This morning i woke up to find out my bathroom paint was almost dripping off the wall. Checked in the cupboard and the A Class unit was boiling hot and red light repeatidly flashing. I have took the front off panel off tried resetting the machine but doesnt change anything. The digital reading inside shows the one above set 1 (bottom right hand corner) red light flashing, which i have read mean machine has locked out? and the one above set 2 It shows a U shape. Which again i believe means on and off peak ON, and the bottom line Sensor 5 calling?
I have rang the manufacturor and they say my tank might be empty which it almost was but letting all that steam off i wouldnt expect anything different? and that it might of over heathed but should cool down quickly....

Anyone got any ideas on what the fix could be?

Thanks.

let it cool down first.
check you water level it needs to be nearly half full and check 2-3 times per year because it is a thermal store it will heat and cool and needs stored water to replenish itself.
hope this helps
mark.
www.gledhill-repair.co.uk